Common diseases, such as type 2 diabetes and post-traumatic stress disorder (PTSD), are more prevalent in people with closely related parents, a new study has shown.
Scientists at the Wellcome Sanger Institute, Cambridge, and Queen Mary University, London, have developed a new research method to analyse genetic data for the degree of relatedness and risk of disease. After removing sociocultural factors, they found that individuals whose parents were first cousins had an increased risk of 12 common diseases.
Dr Hilary Martin, senior author of the paper published in Cell and group leader at the Wellcome Sanger Institute, said 'The findings have the potential to inform disease risk prediction as well as future research efforts to identify specific genetic variants associated with these diseases… This could be used to help stratify individuals for earlier screening and identify potential drug targets.'
The research team analysed genetic data from a combined total of over 400,000 UK residents, nearly 24,000 of whom were British South Asians – predominantly Bangladeshi and Pakistani – from the Genes & Health database. The authors found that only two percent of individuals with European ancestry were offspring of second cousins or closer, compared with around 30 percent of individuals with South Asian ancestry.
The research group restricted their analysis to approximately 5700 people whose parents were thought to be first cousins, based on their genetic data. This rate of consanguinity did not always yield the same level of autozygosity, with the degree of identical genetic material inherited ranging from four to 15 percent. The researchers confirmed that autozygosity levels did not correlate with sociocultural and environmental factors, such as religion, education, or diet, which could influence health traits themselves.
This then confirmed that any relationship between consanguinity and disease risk in this study was due to biological effects. Among the 61 complex diseases and disorders evaluated in this study, the research team found an association of 12 diseases with autozygosity, including asthma, type 2 diabetes, and PTSD.
The results of this study suggested that consanguinity may account for approximately ten percent of type 2 diabetes cases among British Pakistanis and three percent among British Bangladeshis.
'By empowering people with the knowledge to make informed health decisions, we can help tackle the health disparities in our communities, especially in diseases like type 2 diabetes,' said Ahsan Khan, chair of the Genes & Health community advisory board and councillor at Waltham Forest.