Skip to 0 minutes and 16 secondsThere's one particular family I can think of with three boys in two sibships with childhood or congenital cataract. Childhood cataract is uncommon, affects about 3 in 10,000 individuals. And these three boys have got the cataract associated with behavioural difficulties and learning disability. And the case in point is to try and understand what the cause of their cataracts might be. Actually, if you go back and look at the clinical notes to each of the individuals, they're enormously thick. And you can see that for each of the individuals in turn.
Skip to 1 minute and 2 secondsThey've had many investigations, many of the same investigations in fact, trying to understand from a biochemical point of view or using MRI, a range of investigations, precisely what the cause of the cataracts might be to try and improve the management of the case. And also to understand what the risks for the future might be.
1. Clinical Investigations
In the following video we will hear Professor Graeme Black Consultant Clinical Geneticist at The Manchester Centre for Genomic Medicine describe a case study where next generation sequencing technology has had a real impact on the diagnosis of two young boys with a rare genetic condition.
About Congenital Cataract (CC)
Congenital Cataract (CC) is the leading cause of blindness and visual impairment in children 1, clinically classified according to the anatomic location of the opacity in the lens.2 The genetic form of this condition is inherited in one of three modes including autosomal dominant, autosomal recessive and X-linked3, it can also be associated with metabolic diseases which means treatment to prevent progression is possible 4. It lends itself to a gene panel genomic testing approach as it is a highly heterogeneous condition meaning that variants associated with this disease have been found in well over a hundred genes to date, mainly affecting lens development1.
In this case the DNA of two boys of the same family with juvenile onset cataracts were sent for sequencing using the Manchester congenital cataract gene panel, a panel of 114 genes. This panel is representative of the genes linked to both the hereditary forms of this condition and also the genes associated with the most common forms of syndromic cataract. Further details of this test can be found in the gene dossier submitted by the Diagnostic Laboratory by visiting the UK Genetic Testing Network (UKGTN) website Manchester congenital cataract gene panel.
Next-generation Sequencing in the Diagnosis of Metabolic Disease Marked by Pediatric Cataract. R. L. Gillespie et al Ophthalmology. 2016 Jan;123(1):217-20
Personalized diagnosis and management of congenital cataract by next-generation sequencing. R. L. Gillespie et al Ophthalmology, 2014 Nov;121(11):2124-37
The use of autozygosity mapping and next-generation sequencing in understanding anterior segment defects caused by an abnormal development of the lens. R. L. Gillespie, I. C. Lloyd & G. C. Black Human Heredity. 2014;77(1-4):118-37
- Rahi et at 2001 br J Opthalmology 85: 1049-51 Ascertainment of children with congenital cataract through the National Congenital Anomaly System in England and Wales.
- Huang and He 2012 Molecular characteristics of inherited congenital cataracts Vol 53: 347-357 in European Journal of Medical Genetics
- J.F. Hejmancik 2008 Semin Cell Dev Biol 19:134-139 A nonsense mutation of CRYGC associated with autosomal dominant congenital nuclear cataracts and microcornea in a Chinese pedigree
- Churchill A. and J. Graw. 2011. Phil. Trans. R. Soc. 366:1234-1249 The ocular lens: a classic model for development, physiology and disease
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