Microphthalmos and colobomata among mentally retarded individuals.

Among 993 visually impaired mentally retarded persons 86 had microphthalmos or colobomata. The aetiology was prenatal infections in 16 cases, 6 had chromosomal aberrations, syndromes previously described were present in 14, private syndromes in 3. Although the malformation association observed in 36 patients had been previously described, it was impossible to assess whether the individual cases were due to environmental or genetic causes, and in 11 cases the associations were apparently previously undescribed.