Foveal Hypoplasia 2

Clinical Characteristics

Ocular Features:

The cardinal feature in this condition is foveal hypoplasia which is characterized by the lack of a foveal depression and continuity of all neurosensory layers across the foveal area as revealed by OCT. This is accompanied by poor visual acuity, nystagmus, and strabismus. Hypopigmentation of the immediate area has also been reported in some patients. Visual acuity in one study of 9 patients ranged from 20/50 to 20/200. The ERG and flash VEP can be normal. Color vision has been described as normal in some individuals.

Dysgenesis of the anterior segment seems to be family-specific and consists of Axenfeld anomaly or embryotoxon.

Systemic Features:

In most cases the only features are foveal hypoplasia with or without anterior chamber anomalies. Three affected sisters in one family were reported to have mild developmental delay.

Genetics

Homozygous mutations in SLC38A8 [1] (16q23.3) are responsible for this disorder.

For a somewhat similar condition of foveal hypoplasia see FVH1 [2] (136520 [3]), which is, however, caused by a different mutation and inherited in an autosomal dominant pattern.

Treatment

Treatment Options:

There is no known treatment.

References

Article Title:

Isolated foveal hypoplasia with secondary nystagmus and low vision is associated with a homozygous SLC38A8 mutation [4]

Perez Y, Gradstein L, Flusser H, Markus B, Cohen I, Langer Y, Marcus M, Lifshitz T, Kadir R, Birk OS. Isolated foveal hypoplasia with secondary nystagmus and low vision is associated with a homozygous SLC38A8 mutation. Eur J Hum Genet. 2014 May;22(5):703-6.

PubMed ID:

A new phenotype of recessively inherited foveal hypoplasia and anterior segment dysgenesis maps to a locus on chromosome 16q23.2-24.2 [5]

Pal B, Mohamed MD, Keen TJ, Williams GA, Bradbury JA, Sheridan E, Inglehearn CF. A new phenotype of recessively inherited foveal hypoplasia and anterior segment dysgenesis maps to a locus on chromosome 16q23.2-24.2. J Med Genet. 2004 Oct;41(10):772-7.

PubMed ID:

15466012