February 2017 | Feabhra 2017

Medical Genetics Research Success

Sat, 11 February 17 12:06

Dr James O’Byrne together with Dr Sally Ann Lynch (Children's University Hospital, Temple Street) have recently had double publication success in the American Journal of Medical  Genetics.  Together with the Temple Street craniofacial team led by Mr Dylan Murray, the 3D CT skull images of a child with a de novo chromosomal translocation & craniosynostosis, featured on the front cover of the January edition of the journal.

Drs O’Byrne and Lynch have also just published online the first Irish cross border epidemiological study involving the genetics centres in both Dublin & Belfast. The study looked at the incidence of fragile X syndrome (FXS) in both jurisdictions. Dr Deirdre Donnelly in Belfast helped provide the Northern Ireland data while Dr. Michael Sweeney and Prof. David Barton in the molecular genetics laboratory in Crumlin, Dublin helped compile the data from the Republic of Ireland.

The analysis of patients from one fairly homogeneous population under two distinct health care systems acted as an excellent internal control, ensuring that any gross ascertainment bias would be obvious. The study showed a very low incidence of FXS in the island of Ireland (male incidence of approx.1 in 10,600 and a female incidence of approx. 1 in 43,000); far lower than most of the published estimates to date. This may indicate that FXS is not the most common inherited cause of intellectual disability.

The authors postulate that a number of factors may have contributed to the low incidence of FXS such as a traditional high maternal age or a relative lack of the FXS gene mutation in our ancestors. An important observation was the extremely low pick up rate of FXS in females which suggests that girls are being under-tested. Many girls present with only mild symptoms and often not until school age reducing their chances of being investigated by a paediatrician.