Nanophthalmos AD
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
In the family reported, vision ranged from NLP to 20/20. Refractive errors ranged from +8.25 to +15.50 D (mean +11.8 D). Axial length ranged from 16.90 to 18.46 mm with a mean of 17.6 mm. Angle closure glaucoma was diagnosed in 6 of 16 (37%) patients. Thickened sclera with prominent scleral vessels was described in affected family members. Optic nerve drusen are often present and increased tortuosity of the retinal vessels has been described.
Systemic Features
No systemic abnormalities have been reported in spite of the fact that the TMEM98 gene is widely expressed in body tissues.
Genetics
Inheritance
This is an autosomal dominant disorder resulting from a missense mutation in exon 8 of the TMEM98 (17p12-q12) gene. The mutation has been reported in a single Australian family.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission