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Skip to 0 minutes and 16 secondsHaving done those investigations, but given that three individuals in the family, the wider family, were affected, it was clear that this is a genetic condition. In fact, childhood cataract in about 70% of cases is known to have a genetic basis caused by faults in a range of different genes. And the genetic testing that we've implemented in the Center for Genomic Medicine enables us, through Next-Generation Sequencing, to sequence all of those genes at once. So that was what was implemented through the testing service. And then, the bioinformaticians studied that data to look at that.

Skip to 1 minute and 5 secondsThey found evidence of a fault in a single gene called CYP27A1 which I'd never heard about, but which is known to cause a condition called cerebrotendinous xanthomatosis, big long word. And I'd never heard of it. However, it's known to be associated with childhood cataract, like the boys have got, and with a progressive neurological decline that begins with behavioral problems and learning difficulties, but is progressive and very distressing. It's also associated with premature atherosclerosis and heart disease, which leads to death in early adult life. So, a devastating diagnosis from molecular testing.

Skip to 1 minute and 58 secondsIt underlined to me how difficult it is with rare diseases, where you're not aware of all of the pantheon of rare diseases, how difficult it is to make such a diagnosis. But the important thing for us is that this is a treatable condition. So having got that result, we went back to the family and undertook specific biochemical tests that confirmed the diagnosis, so from a molecular diagnosis to a confirmed clinical diagnosis. And then, they were put on the treatment which is oral medications. It's known that that treatment can lead to a prevention of the heart disease and actually to no progression in the neurological decline.

Skip to 2 minutes and 52 secondsAnd so that's a classic example of a rare condition where, through molecular diagnosis, we've come to a personalized strategy for both management and treatment and, from the family's point of view, a profound effect. Importantly, since then, in the wider family, two other individuals have been born and been tested and been treated within the first year of life.

3. Management and Impact

Professor Graeme Black describes the clinical diagnosis of Cerebrotendinous Xanthomatosis in the two boys caused by a variant in the gene CYP27A1

More information can be found about this gene and condition here Gene cards CYP27A1, what family of proteins is it a member of?

What effect does a variant in this gene have on the protein?

You can look at this gene in more detail within Ensembl CYP27A1 transcript.

Which chromosome is it found on and how many protein coding exons does it have?

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This video is from the free online course:

Clinical Bioinformatics: Unlocking Genomics in Healthcare

The University of Manchester