Further genetic heterogeneity for autosomal dominant human sutural cataracts

A unique sutural cataract was observed in a 4-generation German
family to be transmitted as an isolated autosomal, dominant trait.
Since mutations in the gamma-crystallin encoding CRYG genes have
previously been demonstrated to be the most frequent reason for
isolated congenital cataracts, all 4 active CRYG genes have been
sequenced. A single base-pair change in the CRYGA gene has been
shown, leading to a premature stop codon. This was not observed in
170 control individuals. However, it did not segregate with the
disease phenotype. This is the first truncating mutation in an
active CRYG gene without a dominant phenotype. As the CRYGA
mutation did not explain the cataract, several other candidate loci
(CCV, GJA8, CRYBB2, BFSP2, MIP, GJA8, central pouch-like, CRYBA1)
were investigated by micro-satellite markers and linkage analysis,
but they were excluded based on the combination of haplotype
analysis and two-point linkage analysis. The phenotype in this
family is due to a mutation in another sutural cataract gene yet to
be identified.