Nance–Horan syndrome
Nance–Horan syndrome (NHS) is a rare genetic disorder characterized by congenital cataracts, dental anomalies, and distinctive facial features. It is an X-linked recessive condition, meaning it primarily affects males, while females are typically carriers and may exhibit milder symptoms.
Clinical Features[edit | edit source]
Individuals with Nance–Horan syndrome often present with:
- Congenital cataracts: Clouding of the lens of the eye present at birth, leading to visual impairment.
- Microcornea: Abnormally small cornea.
- Dental anomalies: Including screwdriver-shaped incisors, supernumerary teeth, and delayed dental eruption.
- Facial dysmorphism: Features such as a long face, large anteverted ears, and a broad nasal bridge.
- Intellectual disability: Varying degrees of cognitive impairment are observed in some individuals.
Genetics[edit | edit source]
Nance–Horan syndrome is caused by mutations in the NHS gene located on the X chromosome. The NHS gene is responsible for encoding a protein involved in the development of the eyes, teeth, and brain. Due to its X-linked recessive inheritance pattern, males with a single mutated copy of the gene exhibit the full spectrum of symptoms, while females with one mutated copy are typically carriers and may show milder manifestations.
Diagnosis[edit | edit source]
Diagnosis of Nance–Horan syndrome is based on clinical evaluation, family history, and genetic testing to identify mutations in the NHS gene. Prenatal diagnosis is possible if there is a known family history of the disorder.
Management[edit | edit source]
Management of Nance–Horan syndrome is symptomatic and supportive, including:
- Surgical intervention for cataracts to improve vision.
- Regular dental care to address dental anomalies.
- Educational support and therapies for individuals with intellectual disabilities.
Epidemiology[edit | edit source]
Nance–Horan syndrome is a rare disorder, with its exact prevalence unknown. It has been reported in various populations worldwide.
History[edit | edit source]
The syndrome was first described by Walter E. Nance and Mary Horan in 1974, who identified the characteristic features and inheritance pattern of the disorder.
See Also[edit | edit source]
Related Pages[edit | edit source]
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