MICROPHTHALMOS, CORNEAL OPACITY, MENTAL RETARDATION, AND SPASTIC CEREBRAL PALSY; AN OCULOCEREBRAL SYNDROME

Congenital Bilateral Severe Microphthalmia with Mental Retardation and Cerebral Palsy: Chromosome Aberration, 46, XY, t (2;6)(q31;q24)

Congenital bilateral anophthalmia and microphthalmia are rare conditions, with overall prevalence in one study set at 1.0 per 10,000 births. We report here a case of congenital bilateral severe microphthalmia with mental retardation and cerebral palsy. The patient was man aged 38 years with a chromosome aberration, namely a balanced translocation: 46, XY, t (2;6)(q31;q24). He had no other malformations apart from the severe microphthalmia. CT of the head showed no significant abnormal findings in the brain, but rudimentary eyeballs and external ocular muscles in the bilateral orbits. There was no family history of anophthalmia, microphthalmia, mental retardation or cerebral palsy. His mother had not used any medications or excessive alcohol during gestation. Putative genes of anophthalmia and microphthalmia reported to date include PAX6 (Glaser T et al 1994) and CHX10 (Ferda Percin E et al 2000). Further, some loci of these conditions have been reported (Graham CA et al 1991; Bessant DAR et al 1998; Morle L et al 2000: Forrester S et al 2001: Ng D et al 2002). To our knowledge, however, this is the first report of nonsyndromic microphthalmia or anophthalmia with chromosome 2q31 or 6q24 aberration. We consider that the putative gene may be located on the brake points of chromosome 2 and 6.

An update on microphthalmos and coloboma. A brief survey of genetic disorders with microphthalmos and coloboma

This is a brief survey of more than 100 syndromes in which microphthalmos and/or coloboma appear. It is suggested that the disorders be assessed systematically by consecutive discussions of their aetiology, morphology and embryology.

Microcephaly: genetic counselling and antenatal diagnosis after the birth of an affected child

We describe the clinical and genetic details of a series of microcephalic patients who were referred to the Genetic Counselling Service for the West of Scotland. There were 29 isolated cases of microcephaly and 9 families with recurrent microcephaly. The sib recurrence risk was 19%, which reflects the high incidence of autosomal recessive microcephaly in this series. There was evidence for several varieties of recessive microcephaly. The most frequent, affecting 5 sib pairs, was associated with spastic quadriplegia, seizures, and profound mental handicap. In 15 families with one microcephalic child, prenatal diagnosis by serial ultrasound scans was undertaken in 21 subsequent pregnancies. Four recurrences of microcephaly were detected in the third trimester and one recurrence was missed because no scans were performed after 24 wk gestation when the ultrasound measurements indicated satisfactory head growth. The main reason for late diagnosis of affected fetuses was that head growth did not slow appreciably until the last trimester. The high recurrence risk in this prospective series emphasizes the contribution of autosomal recessive inheritance of microcephaly amongst patients of our Genetic Counselling Service.

Phenotypic variation in the del(12p) syndrome

Previous reports suggested the existence of a del(12p) syndrome. Phenotypic abnormalities associated with del(12p) appear to be mental retardation, microcephaly, and micrognathia. The patient with del(12p) reported here was normocephalic and large for gestational age. She probably had sclerocornea, a finding not previously associated with del(12p). Phenotypic variation in del(12p) syndrome is probably caused by differences in the size of the deleted segment and/or the presence or absence of mutant genes on the homologous 12p segment.

Keratoconus posticus circumscriptus, cleft lip and palate, genitourinary abnormalities, short stature, and mental retardation in sibs

This paper describes two sibs in each of whom Keratoconus posticus circumscriptus is associated with multiple abnormalities. These include short stature, mental retardation, cleft lip and palate, and vertebral anomalies. The authors have been unable to trace any former reports of an identical condition and suggest that the findings in these children may represent a previously unrecognised malformation syndrome showing probable autosomal recessive inheritance.

Genetics of microphthalmos

This is a survey of the genetics of microphthalmos and the heritable syndromes in which microphthalmos occurs. New syndromes are delineated such as the autosomal dominant anophthalmos-microphthalmos-coloboma syndrome, the autosomal dominant microphthalmos, microcephaly, lacunar retinal atrophy syndrome, the autosomal recessive anophthalmos-microphthalmos-coloboma syndrome, the autosomal recessive syndrome with anophthalmos or microphthalmos and genital malformations, and the autosomal recessive syndrome with microphthalmos, microcephaly and retinal falciform folds. Nanophthalmos is described as a poorly defined phenotype and rejected as a genotype. Several other genetic entities with microphthalmos are reviewed and recent descriptions are surveyed.

Prognosis for education of children with bilateral congenital microphthalmus

Retrospective study of 34 patients with bilateral microphthalmus and follow-up of 30 of these revealed mental retardation of seven, an incidence equal to or less than reported by others. Of greater import is the number of highly educated or extremely good students, a finding not previously reported. Familial incidence of microphthalmus was low (4 probable but unproved cases). It seems that in counseling parents of children with microphthalmus we should be optimistic about the future achievement of these children. Support should be provided during their learning years, and we must promote better acceptance by the community, particularly in regard to employment.

Adducted thumb syndromes

The adducted thumbs syndrome is characterized by cleft palate, microcephaly, and dysmyelination. A fifth case of this syndrome is presented. Several other syndromes which may present with adducted thumbs are reviewed and re-assessed. The original contributions consist of discussions of (1) the possible pathogenesis of adducted thumbs in the congenital clasped thumb syndrome, and (3) the significance of adducted thumbs as a possible marker in sex-linked hydrocephalus.