DNA test accurately diagnoses rare diseases

Advanced DNA testing for congenital cataracts can quickly and accurately diagnose a number of rare diseases marked by childhood blindness, according to a study published online in Ophthalmology.

Researchers at the University of Manchester, UK, used a DNA sequencing technology called targeted next-generation sequencing on 36 individuals diagnosed with bilateral congenital cataracts. Using a single diagnostic test, the researchers checked for mutations in the 115 genes known to be associated with congenital cataracts.

In 75% of the individuals tested, the DNA test determined the exact genetic cause of the congenital cataracts based on the mutations.

DNA testing one gene at a time would have taken years to complete; the researchers in this study sped up diagnosis to a matter of weeks by testing for mutations in all 115 known congenital cataract genes at one time. The results hold promise for faster and less costly diagnoses, earlier treatment and genetic counselling for affected families.

"There are many diseases that involve congenital cataracts, but finding the exact reason was always difficult," said Graeme Black, DPhil, professor of genetics and ophthalmology at the University of Manchester, and strategic director of the Manchester Centre for Genomic Medicine. "Even with a family history, diagnosing these rare diseases was always a bit of a shot in the dark."

To read an abstract of the study, click here.