Nance–Horan syndrome

Nance–Horan syndrome
	File:X-linked dominant.svg
Synonyms	NHS
Pronounce
Specialty	Medical genetics
Symptoms	Cataracts, dental anomalies, facial dysmorphism, intellectual disability
Complications	N/A
Onset	Congenital
Duration	Lifelong
Types	N/A
Causes	Mutations in the NHS gene
Risks	Family history of the condition
Diagnosis	Genetic testing, clinical evaluation
Differential diagnosis	Marfan syndrome, Down syndrome, Oculodentodigital dysplasia
Prevention	N/A
Treatment	Surgical removal of cataracts, special education, dental care
Medication	N/A
Prognosis	Variable, depending on severity of symptoms
Frequency	Rare
Deaths	N/A

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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]

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]

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]

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]

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]

Nance–Horan syndrome is a rare disorder, with its exact prevalence unknown. It has been reported in various populations worldwide.

History[edit]

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.