What Is Prader-Willi Syndrome?
Prader-Willi syndrome is a complex genetic circumstance that influences many parts of the frame. In infancy, this circumstance is characterized by way of vulnerable muscle tone (hypotonia), feeding difficulties, terrible increase, and not on time improvement. Beginning in childhood, affected people develop an extreme starvation, which results in continual overeating (hyperphagia) and obesity. Some humans with Prader-Willi syndrome, especially people with obesity, also develop type 2 diabetes (the most common shape of diabetes).
People with Prader-Willi syndrome typically have slight to moderate highbrow impairment and learning disabilities. Behavioral troubles are not unusual, which includes temper outbursts, stubbornness, and compulsive behavior such as selecting at the skin. Sleep abnormalities can also occur. Additional functions of this situation include different facial features together with a narrow brow, almond-fashioned eyes, and a triangular mouth; short stature; and small arms and fat. Some people with Prader-Willi syndrome have surprisingly truthful skin and light-colored hair. Both affected adult males and affected females have underdeveloped genitals. Puberty is behind schedule or incomplete, and most affected people are unable to have kids (infertile).
Prader-Willi syndrome (PWS) is an unprecedented genetic situation that impacts a toddler’s metabolism and causes modifications in the child’s look and behavior. It is marked by using a low muscle tone and terrible feeding throughout early infancy, followed by means of great urge for food after age 2-three years, which ends up in the child becoming obese.
PWS may additionally cause a put off in adolescence milestones and puberty. If unusual weight advantage isn't managed, it could lead to life-threatening complications consisting of sleep apnea, diabetes and coronary heart troubles.
- Prader-Willi (PRAH-dur VIL-e) syndrome is a rare genetic ailment that affects some of bodily, intellectual and behavioral problems. A key characteristic of Prader-Willi syndrome is a consistent experience of hunger that typically begins at about 2 years of age.
- People with Prader-Willi syndrome need to eat continuously due to the fact they never feel complete (hyperphagia), and that they generally have trouble controlling their weight. Many complications of Prader-Willi syndrome are due to obesity.
- Best managed by using a crew technique, diverse professionals can work with you to manage signs and symptoms of this complicated ailment, reduce the danger of growing headaches and enhance the exceptional of lifestyles for the one you love with Prader-Willi syndrome.
Prader-Willi syndrome (PWS) is a genetic multisystem ailment characterized in the course of infancy by means of lethargy, dwindled muscle tone (hypotonia), a susceptible suck and feeding difficulties with terrible weight gain and boom and different hormone deficiency. In adolescence, functions of this sickness include brief stature, small genitals and an excessive urge for food. Affected individuals do not feel glad after completing a meal (satiety). Without intervention, overeating can cause onset of lifestyles-threatening obesity. The meals compulsion calls for consistent supervision. Individuals with extreme obesity might also have an increased threat of cardiac insufficiency, sleep apnea, diabetes, respiratory problems and other extreme situations which could motivate life-threatening complications. All people with PWS have a few cognitive impairment that stages from low regular intelligence with getting to know disabilities to moderate to moderate intellectual disability. Behavioral issues are not unusual and might consist of mood tantrums, obsessive/compulsive conduct, and skin selecting. Motor milestones and language development are frequently delayed. PWS happens due to abnormalities affecting sure genes inside the proximal lengthy arm of chromosome 15 while deleted from the daddy’s chromosome 15 and hence called a genomic imprinting ailment which depends on the sex of the discern donating the chromosome main to the chromosome defect inside the child. These abnormalities normally end result from random (sporadic) errors in egg or sperm development, but are from time to time inherited.
symptoms Prader-Willi syndrome symptoms usually develop during early childhood although they may not become apparent until adulthood Children with this genetic disorder may be small for their age They typically develop motor skills at a slower rate than other children do Prader-Willi syndrome is often marked by behavioral problems such as stubbornness tantrums and self-injurious behavior These problems are caused by the child's frustration over his inability to communicate needs and desires or to perform basic daily tasks.
Prader-Willi syndrome is a rare genetic disorder characterized by an insatiable appetite and an inability to feel fullness after eating Children with this disorder often have low muscle tone short stature small hands and feet and an underdeveloped sex organ Because this condition is caused by a defect on the X chromosome symptoms are seen only in males.
Symptoms Prader-Willi syndrome
The signs of Prader-Willi syndrome are likely because of a disorder of a part of the brain called the hypothalamus. The hypothalamus is a small endocrine organ at the base of the brain that plays an important position in lots of physical functions, including regulating starvation and satiety, frame temperature, ache, sleep-wake balance, fluid balance, feelings, and fertility. Although hypothalamic disorder is thought to result in the signs of PWS, it isn't always but clear how the genetic abnormality causes hypothalamic dysfunction.Signs and signs and symptoms of Prader-Willi syndrome can range amongst people. Symptoms might also slowly alternate over time from early life to adulthood.
Signs and symptoms that may be present from birth include:
Poor muscle tone. A primary signal in the course of infancy is negative muscle tone (hypotonia). Babies may relax with their elbows and knees loosely extended instead of fixed, and they will experience floppy or like rag dolls whilst they are held.
Distinct facial features. Children may be born with almond-fashioned eyes, a narrowing of the pinnacle at the temples, a became-down mouth and a thin top lip.
Poor sucking reflex. Infants might also have a terrible sucking reflex due to reduced muscle tone. Poor sucking makes feeding hard and can result in failure to thrive.
Generally poor responsiveness. A toddler may additionally appear strangely tired, respond poorly to stimulation, have a tough time waking up or have a susceptible cry.
Underdeveloped genitals. Males may additionally have a small penis and scrotum. The testicles can be small or now not descended from the stomach into the scrotum (cryptorchidism). In ladies, the clitoris and labia can be small.
Early childhood to adulthood
Other features of Prader-Willi syndrome seem for the duration of early childhood and stay for the duration of life, requiring cautious control. These features may additionally encompass:
Food craving and weight gain. A classic sign of Prader-Willi syndrome is a steady yearning for meals, resulting in speedy weight advantage, beginning around age 2 years. Constant hunger results in ingesting regularly and eating large quantities. Unusual food-in search of behaviors, consisting of hoarding meals, or eating frozen meals or maybe rubbish, may broaden.
Underdeveloped sex organs. A circumstance referred to as hypogonadism happens whilst sex organs (testes in guys and ovaries in ladies) produce very little sex hormones. This outcomes in underdeveloped sex organs, incomplete or delayed puberty, and in nearly all cases, infertility. Without remedy, women won't begin menstruating until their 30s or may additionally in no way menstruate, and men won't have a lot of facial hair and their voices may additionally by no means absolutely deepen.
Poor growth and physical development. Underproduction of boom hormone can result in quick adult height, low muscle tissues and high body fat. Other endocrine troubles may also consist of underproduction of thyroid hormone (hypothyroidism) or significant adrenal insufficiency, which prevents the body from responding appropriately during strain or infections.
Cognitive impairment. Mild to mild intellectual disability, consisting of problems with wondering, reasoning and hassle-fixing, is a commonplace feature of the sickness. Even those without full-size highbrow incapacity have some getting to know disabilities.
Delayed motor development. Toddlers with Prader-Willi syndrome frequently attain milestones in bodily movement — for instance, sitting up or on foot — later than other children do.
Speech problems. Speech is regularly delayed. Poor articulation of phrases may be an ongoing problem into adulthood.
Behavioral problems. Children and adults might also at instances be stubborn, indignant, controlling or manipulative. They may also throw mood tantrums, in particular whilst denied meals, and might not tolerate modifications in ordinary. They may also expand obsessive-compulsive or repetitive behaviors, or each. Other intellectual health issues, together with tension and skin choosing, may also increase.
Sleep disorders. Children and adults with Prader-Willi syndrome can also have sleep disorders, along with disruptions of the normal sleep cycle and a circumstance wherein respiration pauses in the course of sleep (sleep apnea). These problems can bring about immoderate daylight sleepiness and get worse conduct issues.
Other signs and symptoms. These may additionally encompass small arms and feet, curvature of the spine (scoliosis), hip troubles, decreased saliva drift, nearsightedness and other imaginative and prescient troubles, problems regulating body temperature, a excessive pain tolerance, or a lack of pigment (hypopigmentation) inflicting hair, eyes and skin to be light.
When to see a doctor
Regularly scheduled well-baby visits can help become aware of early symptoms of poor growth and improvement, which may be symptoms of Prader-Willi syndrome or other problems.
If you've got concerns about your infant's health among nicely-infant visits, time table an appointment together with your baby's medical doctor.
Causes Prader-Willi syndrome
PWS takes place when sure sequences of genetic material are missing or not operating--specifically, a section on chromosome 15. The mother and father every skip down one copy of chromosome 15 to their kids. In youngsters who've PWS, the father’s chromosome isn't always running properly. In a few instances, youngsters inherit two copies of chromosome 15 from their mom.
Prader-Willi syndrome is a genetic disorder, a situation resulting from mistakes in one or greater genes. Although the precise mechanisms liable for Prader-Willi syndrome have not been recognized, the problem lies in the genes positioned in a particular region of chromosome 15.
With the exception of genes associated with intercourse characteristics, all genes are available in pairs — one replica inherited out of your father (paternal gene) and one copy inherited out of your mom (maternal gene). For maximum types of genes, if one copy is "active," or expressed, then the other replica also is expressed, even though it's everyday for a few kinds of genes to act on my own.
Prader-Willi syndrome occurs due to the fact certain paternal genes that ought to be expressed are not for any such reasons:
Paternal genes on chromosome 15 are missing.
The child inherited two copies of chromosome 15 from the mother and no chromosome 15 from the father.
There's some error or defect in paternal genes on chromosome 15.
In Prader-Willi syndrome, an illness on chromosome 15 disrupts the normal features of a portion of the brain referred to as the hypothalamus, which controls the discharge of hormones. A hypothalamus that isn't always functioning properly can interfere with methods that result in issues with starvation, boom, sexual development, body temperature, mood and sleep.
In maximum cases, Prader-Willi syndrome is because of random genetic errors and isn't always inherited. Determining which genetic disorder caused Prader-Willi syndrome may be helpful in genetic counseling.
Complications Prader-Willi Syndrome
In addition to having steady starvation, humans with Prader-Willi syndrome have low muscles, so they want fewer than common energy, and they may now not be physically active. This aggregate of factors makes them susceptible to weight problems and the medical problems associated with obesity, including:
Type 2 diabetes
High blood pressure, high cholesterol and heart disease
Other complications, such as an increased risk of liver disease and gallbladder stones
Complications of inadequate hormone production
Complications arising from inadequate hormone production might also consist of:
Sterility. Although there have been a few reports of women with Prader-Willi syndrome turning pregnant, the general public with this disease are not able to have kids.
Osteoporosis. Osteoporosis causes bones to end up susceptible and brittle, so they will spoil effortlessly. People with Prader-Willi syndrome are at an improved hazard of developing osteoporosis due to the fact they've low degrees of intercourse hormones and may additionally have low tiers of growth hormone — both hormones assist and hold robust bones.
Other complications that can result from Prader-Willi syndrome encompass:
Effects of binge eating. Eating big amounts of food quickly, referred to as binge eating, can cause the belly to become abnormally enlarged. People with Prader-Willi syndrome may not document ache and that they do not often vomit. Binge eating can also cause choking. Rarely, someone may additionally eat so much that it causes stomach rupture.
Reduced quality of life. Behavioral troubles can interfere with one's own family functioning, successful education and social participation. They can also reduce the life expectancy of children, teenagers and adults with Prader-Willi syndrome.
Prevention Prader-Willi Syndrome
If you have an infant with Prader-Willi syndrome and would love to have every other baby, consider searching for genetic counseling. A genetic counselor can also assist in deciding your danger of getting every other baby with Prader-Willi syndrome.
How long can you live with Prader-Willi syndrome?
Prader-Willi syndrome can be a lifelong condition that affects the way a person looks and feels People with Prader-Willi syndrome have a constant feeling of hunger They can't control their eating and they may need to eat every few hours Without treatment those with Prader-Willi syndrome can develop life-threatening health problems including heart disease and diabetes They also have trouble sleeping and many experience slow growth as children.
At what age is PWS diagnosed?
Prader-Willi Syndrome is usually first noticed during infancy or early childhood The symptoms are so variable that some doctors may be confused about what to do and it will often take several visits before the correct diagnosis is made This is one of the reasons why Prader-Willi Syndrome is not unusual in adults who initially have been misdiagnosed with depression or an eating disorder When the parents become aware their child has PWS they often recall noticing symptoms shortly after birth such as an inability to maintain weight gain a poor sucking reflex and frequent infections Sometimes these issues are explained away as being due to prematurity since PWS babies are born at an earlier than normal gestation period.
Diagnosis Prader-Willi syndrome
PWS is recognized with a blood test that looks for the genetic abnormalities that are unique to PWS – referred to as a “methylation evaluation.” A FISH (fluorescence in-situ hybridization) takes a look at identifying PWS by way of deletion, however it does not diagnose other varieties of PWS. The methylation taken a look at will identify all forms of PWS and is the desired take a look at for diagnosis. If a methylation taken a look at is executed first, additional checking may be made to decide whether or not PWS is caused by a paternal deletion, UPD, or an imprinting mutation. In instances in which an imprinting mutation is suspected, blood may also be drawn from the parents.
Typically, doctors suspect Prader-Willi syndrome primarily based on signs and symptoms. A definitive prognosis can almost always be made via a blood check. This genetic trying out can discover abnormalities to your toddler's chromosomes that imply Prader-Willi syndrome.
Treatment Prader-Willi syndrome
The remedy of PWS is directed closer to the unique symptoms which might be apparent in every person. Early intervention and strict upkeep to treatment can greatly improve the overall fitness and first-rate of existence for affected individuals and their households. Treatment may also require the coordinated efforts of a crew of experts. Clinical geneticists, pediatricians, orthopedists, endocrinologists, speech therapists, psychologists, dieticians, nutritionists, and different healthcare experts may also want to systematically and comprehensively plan powerful software for the child’s remedy. Genetic counseling may be of benefit for affected people and their families to similarly speak about the situation, offer facts and to cite recurrence dangers. Parents are strongly advocated to undergo appropriate parenting techniques for the behavioral and eating problems related to PWS; such education correlates with higher analysis.
- Specific therapeutic approaches and interventions might also vary, relying upon several factors, such as sickness severity; the presence or absence of certain signs; an individual’s age and preferred health; and/or other factors. Decisions regarding the usage of specific drug regimens and/or other remedies need to be made by physicians and other members of the health care team in careful consultation with the patient based upon the specifics of his or her case; an intensive dialogue of the ability benefits and dangers, which includes feasible facet consequences and long-time period consequences; patient desire; and other suitable elements.
- In toddlers, special nipples or garbage feeding may be used to ensure adequate nutrition. Gavage feeding is a system wherein a small, skinny tube is surpassed via the nostril and mouth to the stomach to at once feed a new child who has feeding difficulties.
- In males, the remedy of hypogonadism with both testosterone or human chorionic gonadotropin may be beneficial all through infancy, doubtlessly growing the scale of the genitalia or prompting testicular descent into the scrotum while cryptorchidism is gift. Although cryptorchidism may additionally every so often clear up spontaneously or with hormone remedy, maximum males may also require surgical remedy.
- Individuals with PWS additionally benefit from increased hormone (GH) therapy, which could help to grow top, enhance lean frame mass, mobility and respiration feature, lower body fat and in the long run improve the greatness of existence. Some studies have proven that GH remedy may also enhance improvement and behavior. In June of 2000, the Food and Drug Administration (FDA) approved the use of human growth hormone for the remedy of children with genetically-confirmed PWS and evidence of growth failure. Studies have shown that the earlier GH remedy is started out the more useful it is and that remedy can begin as early as two to 3 months of age. GH therapy has been shown to improve facial appearance and basic body construct (frame habitus). Development of standardized boom charts for PWS with and without growth hormone remedy have been generated and can be used to monitor the boom parameters at unique intervals in PWS. It is recommended that affected people go through a nap study to stumble on and deal with obstructive sleep apnea earlier than beginning GH therapy because a few reviews propose a link among untimely demise and GH remedy in sure people with PWS (e.G., people with profound hypotonia or weight problems and pre-existing breathing or cardiac issues). However, different researchers have expressed doubt as to whether GH remedy had an instantaneous role in these instances; however , choices concerning GH therapy in people with PWS are greatly made after a session with a pediatric endocrinologist after a nap, have a look at and tests for adrenal gland insufficiency.
- Children with PWS require early intervention to evaluate and deal with issues with motor abilities, highbrow disability, and speech and language improvement. Early intervention may additionally include bodily and occupational therapy, unique training, and speech remedy. An individualized education plan has to be created at the beginning of faculty. Behavioral therapy and, in some instances, psychoactive medicinal drugs together with unique serotonin reuptake inhibitors can be useful to manipulate difficult conduct or psychosis.
- Children should acquire an ophthalmological examination to assess for eye abnormalities doubtlessly associated with PWS such as strabismus and to assess visual acuity. Children have to also be assessed for hip dysplasia and scoliosis that can occur in this patient populace. Evaluation and treatment of sleep disturbance is usually recommended as properly. Some researchers endorse that each one people with PWS be screened for hypothyroidism (which happens with expanded incidence in PWS) and principal adrenal insufficiency.
- During adolescence, an application which includes a low calorie weight loss program, ordinary workout and a strict supervision of food intake and get admission need to be formulated. Strict supervision of food consumption needs to be based upon top, weight and body mass index (BMI). Such a program must begin before signs of weight problems to help to prevent its improvement. Limiting the admission to food may additionally require locking cabinets and refrigerators. Some people might also require diet supplementation, especially for calcium and vitamin D.
- Sex hormones can be replaced at puberty as they are able to stimulate the development of secondary sexual traits and enhance self-image and bone density. In adult males, the usage of such remedy has been arguable due to the fact testosterone alternative by means of monthly injection may make contributions to behavioral troubles in adult males; use of a testosterone patch or gel will avoid this hassle. Sex hormone replacement therapy may additionally boom the hazard of stroke in women, as inside the standard populace, and hygiene problems have to additionally be considered. Sex training and attention of contraception are vital, specifically in women, as not often being pregnant has befell. Decreased waft of saliva may be improved with special toothpastes, gels, mouthwash and gum.
Early diagnosis and treatment can enhance the pleasant lifestyles for people with Prader-Willi syndrome. A group of fitness experts will probably paint with you to manage the condition.
Your group may include a physician who treats hormonal problems (endocrinologist), behavior specialists, a dietitian, bodily and occupational therapists, a mental fitness professional, a geneticist, and different experts as wanted.
Although unique treatments range relying on signs, most children with Prader-Willi syndrome will need the subsequent:
Good nutrition for infants. Many infants with Prader-Willi syndrome have issue feeding due to reduced muscle tone. Your toddler's pediatrician may additionally recommend a high-calorie system or unique feeding techniques to help your infant benefit weight and will monitor your baby's increase.
Human growth hormone (HGH) treatment. HGH remedy in kids with Prader-Willi syndrome enables boom boom, improves muscle tone and decreases frame fat. A medical doctor who treats hormonal problems (endocrinologist) can help decide whether or not your baby would benefit from HGH and discuss any dangers. A sleep to have a look at is normally advocated before beginning a boom hormone remedy.
Sex hormone treatment. Your endocrinologist can also endorse that your baby take hormone alternative remedy (testosterone for males or estrogen and progesterone for women) to top off low tiers of sex hormones. Hormone alternative therapy commonly starts whilst your child reaches the everyday age for puberty and may assist in reducing the threat of developing thinning of the bones (osteoporosis). Surgery can be needed to accurately undescended testicles.
Weight management. A dietitian can help you develop a wholesome, decreased-calorie diet to help control your child's weight at the same time as ensuring right nutrition. A restricted-calorie weight loss program might also require supplemental vitamins or minerals to make sure balanced nutrients. Increasing bodily hobbies and exercise can help manipulate weight and improve bodily functioning.
Treatment of sleep disturbances. Treating sleep apnea and different sleep problems can enhance daylight hours sleepiness and behavioral problems.
Various therapies. Your toddler will probably benefit from a number of treatment plans, including bodily therapy to enhance motion talents and electricity, speech therapy to improve verbal abilities, and occupational remedy to learn regular capabilities. Developmental remedy to learn age-appropriate behaviors, social skills and interpersonal abilities also may help. In the U.S., early intervention applications with these kinds of remedy are normally available for infants and toddlers via a kingdom's health department. During college years, academic planning and help can maximize getting to know.
Behavior management. Setting strict limits on behavior, schedules and getting admission to food and strict supervision of meals consumption can be required. Some people may also need remedy to control behavior troubles.
Mental health care. A mental health expert, including a psychologist or a psychiatrist, may also assist address psychological issues — as an instance, obsessive-compulsive behaviors, skin picking or a temper disorder.
Other treatments. These may encompass addressing precise symptoms or headaches identified by way of eye tests for imaginative and prescient issues, exams for hypothyroidism or diabetes, and examinations for scoliosis.
Transition to adult care
Most humans with Prader-Willi syndrome will want specialized care and supervision throughout their lives. Many adults with the ailment live in residential care centers that enable them to eat healthy diets, live correctly, paintings and experience amusement activities.
As your child techniques adulthood, bear in mind those strategies:
Find local resources and services for adults via your baby's school and organizations including the Prader-Willi Syndrome Association.
Investigate guardianship issues, wills and special needs trusts that address future care and supervision for your child.
Talk to your child's doctor for suggestions about making the transition to adult medical care.
Lifestyle and home remedies
Tips that will help you take care of the one that you love with Prader-Willi syndrome include the subsequent:
Learn about Prader-Willi syndrome. Managing hormone stages and weight can improve development and behavior and prevent headaches. Work with your fitness care team to develop a plan of taking care of handling signs and addressing issues.
Stick to a strict meal plan. Eating a low-calorie food plan is important to hold your baby from turning into obese. Structure mealtime and the form of food to help increase exercises and to help your baby recognize expectations. Use small dishes for serving food. To assist save your binging, keep away from buying high-calorie snacks. Store food out of your baby's reach. Lock pantries, refrigerators and cupboards.
Encourage regular daily activity. Increasing bodily pastime and exercise can assist control weight and enhance physical functioning.
Set limits. Create a firm schedule and set expectations for dealing with behavior. If wanted, talk to your fitness care group about approaches to deal with troubles.
Schedule regular medical care. Talk with your medical doctor about a regular time table of fitness appointments and assessments to test for troubles or headaches associated with Prader-Willi syndrome.
Coping and support
Having a baby with Prader-Willi syndrome is tough and can take loads of staying power. Managing eating problems, behavior and scientific troubles can affect the entire circle of relatives.
Some alternatives for coping and support can consist of:
Talking to a mental health professional. If you're having hassle coping or experience crushed, speak to a mental fitness counselor or therapist.
Joining a support group. Some humans locate it beneficial to speak with others who proportion comparable reviews. Ask your fitness care provider approximately a circle of relatives to assist businesses for your location. Organizations consisting of the Prader-Willi Syndrome Association offer resources, aid groups and educational materials.
Seeking other sources of support. Options for added guidance can include asking about resources of respite care, inquiring for support from family and friends, and taking time in your own pastimes and activities.
Preparing for your appointment
You may begin with the aid of seeing your circle of relatives health practitioners or your child's pediatrician. He or she may also refer you to a pediatric endocrinologist and other specialists as needed.
Here's a few records that will help you prepare for your appointment. Consider taking a family member or buddy alongside for assistance and to help you not forget records.
What you can do
To prepare for the appointment, make a list of:
Any signs and symptoms your child has been experiencing, and for how long
Your child's key medical information, Along with latest ailments, medical situations, and the names and dosages of any medicines, vitamins, herbs or different dietary supplements
Questions you want to ask your doctor
Some basic questions to ask your doctor may include:
What is likely causing my child's signs and symptoms?
Are there any other possible causes for these symptoms?
What kinds of tests does my child need?
What treatment approach do you recommend?
What are the expected results of treatment?
What are the possible side effects of treatment?
How will you monitor my child's health over time?
What is my child's risk of long-term complications?
Can you suggest educational materials and local support services?
What services are available for early childhood development?
What to expect from your doctor
Your medical doctor is likely to ask you some questions. Be equipped to answer them to reserve time to move over factors you need to pay attention to. For example, your doctor may ask extraordinary questions based on your toddler's age.
Questions about your baby:
How often and how much does your baby eat?
Does your baby have any problems sucking?
How well does your baby wake up?
Does your baby seem listless, weak or sick?
Questions about early childhood:
How much does your child eat?
Does he or she constantly look for food?
Does your child eat any unusual items or steal or sneak food?
Does your child show extreme stubbornness or throw tantrums?
Does your child show any other troubling behaviors?
- has been linked to : Doctors first identified Prader-Willi syndrome in 1956 but it has been the subject of study for some time German physician Franz Josef Prader discovered a relationship between the loss of chromosome 15 and a group of patients who displayed similar characteristics including small stature developmental delays cognitive impairment and hypogonadism Medical researchers have since established that Prader-Willi syndrome is caused by the partial deletion of chromosome 15. This leads to a loss of PWS genes which are responsible for regulating appetite and other body weight-related functions It is estimated that 1 out of every 20,000 people suffers from this genetic disorder.