'Using next-generation sequencing, we are now able to identify the cause of cataracts in children in a way that is much faster and more cost-effective than the current method', says Rachel Gillespie, who developed the test.
Congenital cataracts are a leading cause of blindness in children, affecting around 200,000 children around the world every year. It is thought that around half of cases are due to genetic mutations, while the remainder are caused by environmental risk factors during pregnancy - for example, exposure to infections such as rubella.
Mutations in more than 100 genes have been linked to congenital cataracts. Conventional screening methods involve the consecutive testing of each gene separately to determine the precise genetic cause, which is a time-consuming and costly process.
'At the moment, screening for one gene takes around four weeks. There are more than 100 known genes linked to congenital cataracts, so establishing the cause by screening genes individually can sometimes take years', says Gillespie. 'Our test looks at all of these genes in parallel, so patients can be diagnosed much faster and receive the treatment, clinical management and genetic counselling they need'.
As more patients are tested and more knowledge is gained about the genetic basis of the condition, it is hoped that pinpointing the exact mutation responsible will enable doctors to make more accurate predictions, regarding how the cataracts may progress and what the outcome of surgery may be.
Genetic testing can also bring to light more complex conditions, whose symptoms typically do not emerge until later in life. 'In some cases, we have identified that the cataracts aren't just a standalone problem, but a symptom of a more complex syndrome', says Gillespie. 'This includes Warburg micro syndrome and galactokinase deficiency, both rare conditions that are probably under-diagnosed, as warning signs in children can be subtle'.
Rachel Gillespie was talking about her work prior to her presentation 'Next generation sequencing as a powerful means of diagnosis for congenital cataract' at the British Society for Genetic Medicine's annual conference, held at the Liverpool Arena and Convention Centre on Monday 16 September 2013.