# Is Prader-Willi syndrome a hereditary disease passed from parents to children? Canonical page: https://clinicsjo.com/en/faq/is-prader-willi-syndrome-hereditary Language: en Category: pediatrics Publisher: ClinicsJo Published: 2026-09-13T08:09:52.673Z Content updated: 2026-09-13T08:09:52.673Z Translation (ar): https://clinicsjo.com/ar/faq/is-prader-willi-syndrome-hereditary Prader-Willi syndrome is indeed a complex genetic condition affecting multiple parts of the body, but most cases are not inherited directly from parents to children in the traditional sense. This syndrome occurs due to the loss of function of specific genes in a particular region of chromosome 15. Normally, a person inherits one copy of this chromosome from each parent. Some genes in this region are active only on the copy inherited from the father. ## How does Prader-Willi syndrome occur? In the majority of cases (approximately 70%), Prader-Willi syndrome occurs when a part of the paternal chromosome 15 is deleted in every cell. In this instance, the person loses essential genes in this region because the genes on the paternal copy are deleted, while the genes on the maternal copy are inactive. In about 25% of cases, the affected person inherits two copies of chromosome 15 from the mother instead of one copy from each parent, a condition known as maternal uniparental disomy [\[1\]](). Rarely, the syndrome also occurs due to a chromosomal rearrangement called a translocation, or another genetic change that disrupts the normal silencing of genes on the paternal chromosome 15 [\[1\]](). These genetic changes usually occur as random events during the formation of reproductive cells (eggs and sperm) or in early fetal development, which is why there is typically no family history of the disease in most cases [\[1\]](). ## Can it be passed down genetically? In very rare instances, the genetic change responsible for Prader-Willi syndrome can be inherited. For example, a genetic change that leads to the abnormal silencing of genes on the paternal chromosome 15 can be passed from one generation to the next [\[1\]](). ## Symptoms of Prader-Willi Syndrome Prader-Willi syndrome is characterized by a range of symptoms that change as one ages. In infancy, symptoms include weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Starting in childhood, affected individuals develop an intense sense of hunger that leads to chronic overeating (hyperphagia) and obesity [\[1\]](). Other common symptoms include short stature, small hands and feet, and distinct facial features such as a narrow forehead, almond-shaped eyes, and a triangular mouth. Most affected individuals have mild to moderate intellectual disability and learning difficulties. Behavioral problems are also common, including temper tantrums, stubbornness, and compulsive behaviors such as skin picking. Sleep disorders may also occur [\[1\]](). ## Diagnosis and Care Prader-Willi syndrome can be successfully diagnosed in most infants through genetic testing [\[3\]](). Although there is no cure for the syndrome, many treatments can help improve symptoms. These treatments are based on individual needs and often include strict nutritional supervision, physical therapy, behavioral therapy, and growth hormone therapy [\[3\]](). Most people with Prader-Willi syndrome require specialized care and supervision throughout their lives [\[2\]](). For more information about this syndrome, you can visit [Prader-Willi Syndrome: Symptoms, Diagnosis, and Managing Behavioral and Nutritional Challenges (Arabic)](). ## Medical references - [Prader-Willi syndrome: MedlinePlus Genetics]() - [Prader-Willi Syndrome]() - [About Prader-Willi Syndrome (PWS)]() General health education; not a substitute for individualized clinical assessment. Citation URL: https://clinicsjo.com/en/faq/is-prader-willi-syndrome-hereditary#answer