Cataract 47

A number sign (#) is used with this entry because of evidence that juvenile cataract with microcornea (CTRCT47) is caused by heterozygous mutation in the SLC16A12 gene (611910) on chromosome 10q23. One such family has been reported.

Clinical Features

Vandekerckhove et al. (2007) described a Swiss family in which 11 of 17 living family members in 3 generations underwent ophthalmic assessment and urine analysis. Eleven members had progressive juvenile cataract. Eight members available for clinical examination had bilateral microcornea not associated with microphthalmos. In 6 of these persons renal glucosuria was demonstrated.

Kloeckener-Gruissem et al. (2008) restudied the family of Vandekerckhove et al. (2007), noting that 9 of 12 cataract patients also showed elevated glucose in urine in the absence of other renal or metabolic abnormalities.

Molecular Genetics

In a Swiss family with juvenile cataract with microcornea and renal glucosuria, originally reported by Vandekerckhove et al. (2007), Kloeckener-Gruissem et al. (2008) demonstrated heterozygosity for a nonsense mutation in the SLC16A12 gene (Q215X; 611910.0001). They showed that SLC16A12 has high expression in the eye and kidney and hypothesized that SLC16A12 is important for lens and kidney homeostasis. They suggested that the mutation was responsible for the cataract/microcornea/glucosuria phenotype.

Dhayat et al. (2016) restudied 16 members of the Swiss family reported by Vandekerckhove et al. (2007), and found that of 11 family members with SLC16A12-associated cataract for whom renal data were available, 5 had renal leak glucosuria. Dhayat et al. (2016) identified a heterozygous missense mutation in the renal glucosuria-associated gene SLC5A2 (A89T; 182381.0007) that segregated fully with renal leak glucosuria in the family. They concluded that the previously identified mutation in SLC16A12 was only responsible for the cataract/microcornea phenotype.