Application of Medical Genetics in Paediatric Dermatology

Abstract

It is estimated that about 85% of disease-causing mutations occur in the exon which only constitutes to around 1% of the whole human genome. Whole exome sequencing is very useful in finding the aetiology of previously undiagnosed paediatric diseases which could result in various skin manifestations. Some of the rare monogenic dermatological syndromes can be diagnosed earlier by using this genetic technique. For instance, mutation in the GJB2 gene is very likely the cause of KID (keratitis, ichthyosis, deafness) syndrome which can be found by exome sequencing. On the other hand, this technique also helps to understand disease mechanism of some common dermatological diseases, such as atopic eczema which is closely linked to the mutation of the filaggrin gene found by exome sequencing. In the research setting, exome sequencing has been useful for discovering new genes leading to molecular diagnosis such as finding of mutations in TWIST2 gene of Barber-Say syndrome.