Nance–Horan syndrome

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Nance–Horan syndrome
SynonymsCataract X-linked with Hutchinsonian teeth
X-linked dominant inheritance works differently depending upon whether the mother (left image) or father (right image) is the carrier of a gene that causes a disease or disorder
SpecialtyMedical genetics Edit this on Wikidata

Nance–Horan syndrome is a rare X linked syndrome characterized by congenital cataract leading to profound vision loss, characteristic dysmorphic features and dental anomalies.[1][2] Microcornea, microphthalmia and mild or moderate mental retardation may accompany these features. Heterozygous females often manifest similarly but with less severe features than affected males.

Clinical features[edit]

Dental features:

  • small teeth in males
  • pointed (screwdriver shaped or conical) incisors (sometimes called Hutchinson teeth)
  • incisors with an irregulal incisal edge
  • canines: enlarged and globular; may be dome or bud shaped with trilobed edge
  • premolars and molars: small, round and globular; may have supernumary lobes (mulberry or lotus flower shape)
  • widely separated teeth (diastemma)
  • hypoplastic enamel
  • dental agenesis
  • presence of mesiodents (median incisor behind normal upper incisors)
  • pulp chamber anomalies

Facial features:

Ophthalmic features:

These lead to severe visual impairment in affected males.

Other:

30% of patients also have some degree of intellectual impairment: of these 80% are mildly to moderately affected: the other 20% may have developmental delays and behavior problems.

Carrier females display milder variable symptoms of disease. Ocular signs are present in 90% of heterozygous females. These are typically lens opacities often involving the posterior Y sutures. More rarely dental anomalies and the characteristic facial features may also occur.

Genetics[edit]

This syndrome is due to mutations in the Nance Horan gene (NHS) which is located on the short arm of the X chromosome (Xp22.13).[3]

Diagnosis[edit]

Management[edit]

There is no known cure for this syndrome. Patients usually need ophthalmic surgery and may also need dental surgery

Genetic counseling and screening of the mother's relatives is recommended.

History[edit]

This syndrome was first described by Margaret B. Horan and Walter Elmore Nance in 1974.[4][5]

References[edit]

  1. ^ Walpole, I R; Hockey, A; Nicoll, A (1990). "The Nance-Horan syndrome". Journal of Medical Genetics. 27 (10): 632–4. doi:10.1136/jmg.27.10.632. PMC 1017242. PMID 2246772.
  2. ^ Bixler, D; Higgins, M; Hartsfield Jr, J (1984). "The Nance-Horan syndrome: A rare X-linked ocular-dental trait with expression in heterozygous females". Clinical genetics. 26 (1): 30–5. doi:10.1111/j.1399-0004.1984.tb00783.x. PMID 6467651.
  3. ^ Tug, Esra; Dilek, Nihal F.; Javadiyan, Shahrbanou; Burdon, Kathryn P.; Percin, Ferda E. (2013). "A Turkish family with Nance-Horan syndrome due to a novel mutation". Gene. 525: 141–145. doi:10.1016/j.gene.2013.03.094. PMID 23566852.
  4. ^ Horan, Margaret B.; Billson, F. A. (1974). "X-Linked Cataract and Hutchinsonian Teeth". Journal of Paediatrics and Child Health. 10 (2): 98–102. doi:10.1111/j.1440-1754.1974.tb01098.x.
  5. ^ Nance, WE; Warburg, M; Bixler, D; Helveston, EM (1974). "Congenital X-linked cataract, dental anomalies and brachymetacarpalia". Birth defects original article series. 10 (4): 285–91. PMID 4470901.

External links[edit]

Classification
External resources