This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Pallister-Hall syndrome (PHS) is a genetic disease that affects the development of many parts of the body. Common features include extra fingers and/or toes (polydactyly), extra skin
between the fingers or toes (syndactyly), an abnormal
growth in the brain called a hypothalamic hamartoma, and a malformation of the airway known as bifid epiglottis. The bifid epiglottis in rare cases may lead to respiratory failure. While the hypothalamic hamartoma in most cases does not cause problems, in some cases it may cause neurological problems such as seizures, growth hormone deficiency, precocious puberty, or a deficiency of many hormones (panhypopituitarism) that can result in cortisol deficiency. Other symptoms of PHS may include imperforate anus, abnormalities in the kidneys, heart defects, small genitalia, lack of fingers, nail problems, cleft palate, bifid uvula, and development delay and behavioral problems.
Pallister-Hall syndrome is caused by mutations in the GLI3 gene. Inheritance is autosomal dominant, however, in about a quarter of cases Pallister-Hall syndrome results from a new (de novo) mutation.
The diagnosis of Pallister-Hall syndrome can be made when there is a hypothalamic hamartoma and polydactyly. The genetic test that identifies a mutation in the GLI3 gene confirms the diagnosis. Treatment is based on the symptoms, and may include medication for the early treatment of cortisol deficiency and seizures, surgery for imperforate anus and/or polydactyly, and special education when developmental delays are present. The prognosis depends on which symptoms are present and their severity.
For more information, visit GARD.