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Mental retardation as a result of spontaneous mutations, 27.09.2012

A team of scientists at the University of Zurich working in cooperation with German researchers examined 51 patients suffering from a congenital developmental disorder. Severe intellectual disability often appears to be the result of spontaneous gene mutations and, therefore, is not inherited.

Severe intellectual disability at birth is probably not inherited from the parents but triggered by new mutations. This is in essence what the researchers at the University of Zurich and their colleagues at the Universities of Erlangen and Essen and the Helmholtz Centre in Munich report in the current issue of the medical journal «The Lancet». For many parents, this means that there is only a small recurring risk with further pregnancies.

Anita Rauch, Professor of Medical Genetics at the University of Zurich, and her colleagues from the Institute of Human Genetics at the Helmholtz Centre in Munich used exome sequencing to study the genetic mutations. In other words, the researchers have analyzed the genetic substance that builds proteins and other functional products. The striking result was that only three particular genes were affected in several patients, whereas most genes suffered a mutation only in a single patient. This could mean that mutations in many different genes can cause intellectual disability. As Anita Rauch, the first author of the study explains: «It was, therefore, very difficult until now to diagnose these patients ». Tim Strom from the Institute of Human Genetics at the Helmholtz Centre in Munich adds: «With the help of exome sequencing, mental retardation could be diagnosed significantly earlier in the future with reasonable time and effort. We assume that this method will become a standard procedure.» .

Literature:

Rauch A. et al. Range of genetic mutations associated with severe non-syndromic sporadic intellectual disability. an exome sequencing study. The Lancet. 27 September, 2012. doi: 10.1016/S0140-6736(12)61480-9

Translation of a press release in German from the UZH Mediadesk. Read the original version in German>>