Chorioretinal dysplasia, microcephaly, and mental retardation

Clinical Characteristics
Ocular Features: 

The ocular phenotype has not been well defined in this condition since few families have been reported.  Microphthalmia is present in some patients.  The corneas may be small and there is often some conjunctival growth over the limbus.

The retinal features consist of lacunar depigmentation of the RPE and in some cases resemble the lesions of congenital toxoplasmosis.  Eighty to 90 per cent of patients have areas of atrophic and dysplastic-appearing lesions of the retina and choroid with vascular attenuation.  The edges of lacunae may have patchy hyperpigmentation.  These lesions are usually static but may show mild progression.  Visual acuity is generally stable or only mildly progressive.  However, other patients have a severe reduction in acuity.  ERG responses are reduced.

Systemic Features: 

The amount of microcephaly may be minimal and at least some patients have 'bulging' foreheads.  The amount of mental deficiency varies from mild to severe.  IQ levels are generally in the range of 60-70.   Hypotonia has been reported in more severe cases.  Skull size is usually 2-3 standard deviations below the mean and generally has some frontal prominence.

Genetics

This seems to be an autosomal dominant disorder although no loci or mutations have been identified.  It is likely that the category of disease known as microphthalmia-chorioretinal syndrome consists of a heterogeneous group of disorders.  No locus or specific mutation has been identified.

It differs from the microcephaly, lymphedema, chorioretinopathy syndrome (152950) in which retinal folds, ptosis and lymphedema are associated with a typical facial phenotype.  For other disorders in this database having a somewhat similar phenotype see: chorioretinopahty and microcephaly type 1 (251270) and type 2 (616171).

Treatment
Treatment Options: 

Treatment is supportive.  Low vision aids may be helpful.

References
Article Title: 

References

Warburg M, Heuer HE. Chorioretinal dysplasia-microcephaly-mental retardation syndrome. Am J Med Genet. 1994 Aug 1;52(1):117.

PubMedID: 7977454

Sadler LS, Robinson LK. Chorioretinal dysplasia-microcephaly-mental retardation syndrome: report of an American family. Am J Med Genet. 1993 Aug 1;47(1):65-8.

PubMedID: 8368255