Genetic link between low birth weight and Type 2 diabetes discovered
MedWire News: A genetic link has been discovered between low birthweight and Type 2 diabetes, report researchers in the journal Nature Genetics.
“Our study shows that genes are part of the reason why babies born with a lower birth weight are more at risk of Type 2 diabetes 50 or 60 years later,” commented first author Rachel Freathy (Peninsula Medical School, Exeter, UK).
She added: “It is now important for us to establish how much of the association is due to our genes and how much is due to the environment because this will inform how we target efforts to prevent the disease.”
The investigators carried out a meta-analysis of six genome-wide association studies including a total of 10,623 Europeans recruited from pregnancy/birth cohorts to assess genetic variants that might be linked to birth weight.
They found two strong association signals, which they then followed up in 13 replication studies including 27,591 people.
The single nucleotide polymorphism (SNP) rs900400, located near the genes LEKR1 and CCNL1, and rs9883204, located in the gene ADCY5, were strongly associated with birth weight.
The authors found that individuals who had two variant alleles for the two SNPs were an average 113g lighter at birth than those with one or no variant alleles (24%).
The team says this amounts to the reduction in birth weight associated with a mother smoking 4–5 cigarettes per day in late pregnancy.
Of note, variants in ADCY5 have previously been associated with regulation of glucose levels and Type 2 diabetes susceptibility. In addition, people with lower birth weight have been observed to have increased risk for Type 2 diabetes in adulthood.
The researchers say this finding provides additional evidence of a potential genetic association between lower birth weight and increased Type 2 diabetes risk.
Study co-author Mark McCarthy (University of Oxford, UK) said: “It was a surprise to see such strong genetic effects for a characteristic, such as birth weight, which is subject to powerful influences from so many environmental factors.
“These discoveries provide important clues to the mechanisms responsible for the control of growth in early life and may lead us to a better understanding of how to manage growth problems during pregnancy.”
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By Helen Albert