Childhood cataract gene identified
Genetic material has been analyzed from members of a large Swiss family, the majority of whom suffered from auto-somal dominant juvenile cataract. From the DNA, researchers at ETH Zurich and the University Zurich identified the chromosomal location and exact molecular defect in the coding region of the gene responsible for the type of childhood cataract. Until now, no human disease could be associated with this gene.
The corresponding protein arising from the gene belongs to a family of monocarboxylate transporters which move small molecules across cell membranes. Surprisingly, this genetic defect may also lead to the condition of renal glucosuria, a kidney defect which results in elevated levels of glucose in the urine, but not in blood. The researchers suspect that this genetic defect interferes with homeostasis in the lens as well as in the kidney.
The search for the molecule that is carried by this new transporter across the membrane has now begun.
Since the known environmental risk factors for age-related cataract point to physiological and oxidative damages accumulating over time within the lens, the researchers assume that defects in this newly discovered transporter may also be a cause of age-related cataract. Age-related cataract patients are now being screened to find mutations in this gene.
Understanding the exact function of this transporter may open new venues for non-surgical treatment of cataract.
Elaine Warburton www.geneticsandhealth.com
