A large Indian family consisting of 5 generations containing 33 affected individuals has been described.  This is an autosomal dominant disorder in which a mutation has been found in exon 6 of the CRYBB2 [1] gene (22q11.2-q12/22q11.23).  This region contains four crystallin genes as well as the CRYBP1 pseudogene.  It has been suggested that gene conversion between exon 6 of the CRYBB2 [1] gene and CRYBR1 may be responsible for the phenotype.  Three additional families with identical mutations in the same CRYBB2 [1] exon have been reported and, since each family seems to have a unique phenotype, it is likely that more than a simple bp mutation is responsible for the cataracts.  

Some Coppock-like cataracts [2] (604307 [3]) also result from mutations in CRYBB2 [1] at the same location but others have  mutations in the CRYGC [4] gene.  Type 2 congenital cerulean cataracts [5] (601547 [6]) have also been associated with mutations in the CRYBB2 [1] gene. 

Another autosomal dominant congenital cataract with sutural opacities [7] (600881 [8]) has a slightly different phenotype and results from a mutation on chromosome 17.