Autosomal dominant congenital cataract in a Libyan Jewish family: cosegregation with a reciprocal chromosomal translocation [t(3;5)(p22.3; p15.1)]

Abstract

Purpose: To describe a Jewish family of Libyan ancestry in which autosomal dominant congenital cataract segregates with an apparently balanced reciprocal chromosomal translocation.

Methods: Detailed family history and clinical data were recorded. Cytogenetic studies were performed on 13 family members.

Results: Embryonal cataracts cosegregated through three generations with a balanced chromosomal translocation [t(3;5)(p22.3; p15.1)] while the unbalanced translocation product, 46,XY,-5,+der(5)t(3:5)(p22:p15.1), had multiple congenital anomalies without cataracts.

Conclusions: These observations suggest that an altered function of a gene at one of the translocation breakpoints on chromosome 3p22.3 or 5p15.1 is causally related to cataract development.

Figure 1

Family tree of the Libyan Jewish family. Thirteen family members underwent karyotype analysis (5609108, 5609113, 5609115, 5609116, 5609117, 5609133, 5609106, 5609122, 5609135, 5609123, 5609127, 5609125, and 5609131). Squares: males; circles: females; filled symbols: congenital cataract affected individuals; diagonal lines through symbols: deceased family members; triangles: miscarried embryos.

Figure 3

G-banded partial karyotype and ideogram. The reciprocal translocation between chromosomes 3 and 5 is illustrated. Complete karyotype notation for the rearranged chromosomes is t(3:5)(p22:p15.1). The same chromosomal translocation was found in the following congenital cataract family members: 5609108, 5609116, 5609117, 5609106, 5609125, and 5609135.

Figure 2

Slit lamp retro-illumination photography from an individual carrying the balanced translocation at eight years of age. The cataract is confined to the embryonic lens nucleus with dense sutural opacity surrounded by white concentric punctate opacities.