Microphthalmia, Isolated, with Cataract

Clinical Characteristics
Ocular Features: 

Isolated microphthalmia with cataract is clinically and genetically heterogeneous and remains to be fully delineated.  The cataracts occur congenitally.  Nystagmus was an additional feature in several individuals with MCOPCT2.  The basis for a third type of microphthalmia with cataract (MCOPCT3) is even less certain but microcornea was also present in several members of a single family.  Globe dimensions have not been reported, however, and the criterion for the diagnosis of microphthalmia in reported families is unknown.

Systemic Features: 

Several patients with MCOPCT1 have had mental retardation.

Genetics

Based on genetic data at least three entities may exist but they are discussed in this database as a group because so few families have been reported.  MCOPCT1 follows an autosomal dominant pattern and segregates with a single unknown mutation at 16p13.3.  Another family with a reciprocal translocation t(2;16)(p22.3;p13.3)  involving a breakpoint in the 16p13.3 region seems to support the idea that an altered gene in this location is responsible for the phenotype.  MCOPCT2 also usually follows an autosomal dominant pattern and seems to be caused by mutations in the SIX6 gene (14q23.1).  The mode of inheritance in MCOPCT3 is uncertain since the transmission pattern in one family suggested X-linked dominance while in another family only males were affected.  No mutation or locus has been identified.  

Treatment
Treatment Options: 

Cataract surgery may be beneficial when vision is significantly compromised.

References
Article Title: 

References

Gallardo ME, Rodr??guez De C??rdoba S, Schneider AS, Dwyer MA, Ayuso C, Bovolenta P. Analysis of the developmental SIX6 homeobox gene in patients with anophthalmia/microphthalmia. Am J Med Genet A. 2004 Aug 15;129A(1):92-4.

PubMedID: 15266624

Yokoyama Y, Narahara K, Tsuji K, Ninomiya S, Seino Y. Autosomal dominant congenital cataract and microphthalmia associated with a familial t(2;16) translocation. Hum Genet. 1992 Sep-Oct;90(1-2):177-8.

PubMedID: 1427774

Wettke-Sch?SSfer R, Kantner G. X-linked dominant inherited diseases with lethality in hemizygous males. Hum Genet. 1983;64(1):1-23.

PubMedID: 6873941

CAPELLA JA, KAUFMAN HE, LILL FJ. HEREDITARY CATARACTS AND MICROPHTHALMIA. Am J Ophthalmol. 1963 Sep;56:454-8.

PubMedID: 14064894