Genetics
- Wolf-Hirshhorn syndrome is caused by a partial deletion of the short arm of chromosome 4, specifically in the region of WHSC1 and WHSC2. The critical region for determining the phenotype is at 4p16.3.
- About 87% of cases represent a de novo deletion, while about 13% are inherited from a parent with a chromosome translocation. In the cases of familial translocation, there is a 2 to 1 excess of maternal transmission. Of the de novo cases, 80% are paternally derived.
Incidence
Affects approximately 1 in 50,000 individuals. Wolf-Hirschhorn syndrome affects females more frequently than males, and occurs in people of all ethnic backgrounds.
Symptoms/Characteristics
- Severe to profound mental retardation
- Microcephaly
- Seizures
- Hypotonia
- Occasional abnormalities include heart defects, hypospadias, scoliosis, ptosis, fused teeth, hearing loss, delayed bone age, low hairline with webbed neck, ear tags or pits, and renal anomalies
- Urinary and genitals – malformations or underdevelopment of organs
Facial Features
- Cleft lip and/or palate.
- Strabismus
- Hypertelorism
- Down-turned “fishlike” mouth
- Short upper lip and philtrum
- Small chin
- Cranial asymmetry
- Prominent forehead
- Broad beaked nose
Clinical Management
Treatment for Wolf-Hirschhorn syndrome focuses on the symptoms present. Seizures would be treated with medication, and difficulty eating or swallowing might require a gastrostomy feeding tube. Physical and occupational therapy can help maintain muscle strength and joint mobility. Care by many different specialists may be needed.