By Diane Allingham-Hawkins, PhD, FCCMG, FACMG, Director of the Hayes Genetic Test Evaluation Program
Experts discussed several interesting genetic topics at CCMG on Friday, October 19, 2012. Here’s a brief update on some of the highlights.
Dr. Patricia Blakley, of the University of Saskatchewan, gave a thought-provoking presentation on addictions in individuals with fetal alcohol spectrum disorders (FASD) highlighting the fact that children with FASD are more likely to abuse nicotine, drugs, and alcohol later in life. Shockingly, these children often start using alcohol and drugs in their first decade, making early interventions critical. Dr. Blakley indicated that there is a clear interplay between genetics and environmental factors in FASD but added that further research is needed to elucidate these factors.
In another session, Dr. Brenda Gerall and Ms. Julia Tagoe, of the University of Calgary, reported on the increased incidence of arrhythmogenic right ventricular cardiomyopathy (ARVC) in the Hutterite population. Hutterites are a religious group dating from the 16th century that has a “community of goods” philosophy, with a minimization of self identity and a maximization of community identity. Communal living is the norm with 100 to 150 people living in a settlement. ARVC is an inherited cardiac disorder characterized by life-threatening arrhythmias, with the first symptom often being sudden cardiac death. Dr. Gerall and Ms. Tagoe reported the identification of a variant in the DSC2 gene in a large Hutterite family with several instances of sudden cardiac death in children. Further research revealed that the variant was present in 9.4% of the Hutterite population; however, although ARVC is usually an autosomal-dominant condition, carriers of this particular variant do not fulfill diagnostic criteria for ARVC, suggesting that this particular variant may be functioning in an autosomal-recessive manner. More research is needed, however, to ensure that carriers are not at risk, and this uncertainty presents a genetic counselling challenge in this population.
Dr. Alan Rosenberg, of the University of Saskatchewan, provided an interesting discussion of the earliest origins of health and disease and suggested that effective treatment of childhood illnesses requires a greater understanding of the earliest origin of disease, rather than waiting until symptoms develop.
In the final talk of the morning session, Dr. Richard Huntsman, of the University of Saskatchewan, provided a very interesting presentation on Cree leukodystrophy. Leukodystrophy is a genetically heterogeneous disease of the cerebral white matter, which includes neuronal axons and glial cells. Cree leukodystrophy was first described in Cree and Chipewyan infants in Northern Quebec and Manitoba. A devastating illness, Cree leukodystrophy is characterized by the complete destruction of the cerebral white matter following a febrile illness leading to severe neurological decline in a previously normal baby. The disease progresses to increasing lethargy, progressive spasticity, and seizures with death within days or months. Research has shown that a specific variant in the eIF2B5 gene was introduced into the Cree populations by Scottish fur traders, as a similar disease known as vanishing white matter disease has been observed in Scotland. However, despite being caused by the same genetic variant, the disease is much more severe in Cree and Chipewyan infants and Dr. Huntsman speculated that there may be additional genetic modifying factors and/or specific environmental factors that contribute to the severity of the disease.