Researchers have found a fast, precise and cost-effective way to help ensure that children with congenital cataracts get the right diagnosis.
Treatment and advice for congenital cataracts currently varies widely due to the difficulty of accurately identifying the cause, however a team from the Manchester Centre for Genomic Medicine used next-generation DNA sequencing to assign the problem to specific genes, making earlier and more appropriate care possible.
Congenital cataracts accounts for about 10% of childhood blindness and can mean that a child’s visual development is disrupted, leading to significant sight loss and blindness. They can also be the first sign of a number of more complex conditions, involving other parts of the body.
Study lead Professor Graeme Black said: "Next-generation DNA sequencing will transform research into congenital cataracts. We will be able to gain a better understanding of how specific genetic mutations affect proteins in the lens and of the cataract-forming biomechanical pathways. It could also lead to insights into the pathology of the more common age-related cataracts and to the development of novel gene therapies."
Until this breakthrough, the cause of an individual child’s congenital cataracts has been determined via a complex series of clinical tests, as well as genetic testing for the most likely genetic fault, based on family history.
Pinpoint a precise genetic cause of cateracts
This process can delay diagnosis and treatment and makes it hard to advise the family on risk to future children. It is also costly to the NHS. More than 110 different cataract-causing genes have already been identified and not enough is known about the relationship between a particular genetic fault and an individual’s clinical symptoms.
In this study, which was funded by the charity Fight for Sight, PhD student Rachel Gillespie used DNA from 36 individuals with congenital cataracts. Existing medical records indicated that 16 of the patients had cataracts as part of a wider condition (‘syndromic’ congenital cataracts), while 20 had cataracts alone (‘non-syndromic’ congenital cataracts’).
Results showed that next-generation DNA sequencing was able to pinpoint a precise genetic cause in 75% of cases overall. A likely genetic fault was found in 85% of patients in the non-syndromic group, and in 63% of the syndromic group.
Dr Dolores M Conroy, Director of Research at Fight for Sight, concluded: "This study demonstrates the clinical usefulness of this test, and it is great that this test is now available on the NHS by referral to Manchester Centre for Genomic Medicine.
"It will enable better, individually focussed care pathways and more accurate genetic counselling. Ultimately, this new diagnostic test will improve outcomes for children born with cataracts."
Read the results in full at http://bjo.bmj.com/content/early/recent