Why Is Mom’s Type 1 Diabetes Half as Likely as Dad’s to Pass to Child?

TOPLINE:

Young and adult children of mothers with type 1 diabetes are almost half as likely be diagnosed with this condition compared with those with affected fathers, even with a similar genetic risk score.

METHODOLOGY:

• Individuals with a family history of type 1 diabetes face 8-15 times higher risk for this condition than the general population, with the risk of inheritance from mothers with type 1 diabetes being about half that of fathers with type 1 diabetes; however, it is unclear if the effect continues past childhood and what is responsible for the difference in risk.
• Researchers performed a meta-analysis across five cohort studies involving 11,475 individuals diagnosed with type 1 diabetes aged 0-88 years to evaluate if maternal type 1 diabetes conferred relative protection only to young children.
• They compared the proportion of individuals with type 1 diabetes with affected fathers versus mothers and explored if this comparison was altered by the age at diagnosis and the timing of parental diagnosis relative to the birth of the offspring.
• Lastly, the inherited genetic risk for type 1 diabetes was compared between those with affected mothers versus fathers using a risk score composed of more than 60 different gene variants associated with type 1 diabetes.

TAKEAWAY:

• Individuals with type 1 diabetes were almost twice as likely to have a father with the condition than a mother (odds ratio, 1.79; P < .0001).
• The protective effect of maternal diabetes was seen regardless of whether the individuals were diagnosed with type 1 diabetes before or after age 18 years (P < .0001).
• Maternal diabetes was linked to a lower risk for type 1 diabetes in children only if the mother had type 1 diabetes during pregnancy.
• The genetic risk score for type 1 diabetes was not significantly different between those with affected fathers versus mothers (P = .31).

IN PRACTICE:

“Understanding why having a mother compared with a father with type 1 diabetes offers a relative protection against type 1 diabetes could help us develop new ways to prevent type 1 diabetes, such as treatments that mimic some of the protective elements from mothers,” study author Lowri Allen, MBChB, said in a news release.

SOURCE:

The study was led by Dr. Allen from the Diabetes Research Group, Cardiff University, Cardiff, Wales, and was published as an early release from the annual meeting of the European Association for the Study of Diabetes.

LIMITATIONS:

This abstract did not discuss any limitations. The number of individuals and parents with type 1 diabetes in the meta-analysis was not disclosed. The baseline risk for type 1 diabetes among individuals with a mother, father, or both or no parent with type 1 diabetes was not disclosed. The number of people with type 1 diabetes under and over age 18 was not disclosed, nor were the numbers of mothers and fathers with type 1 diabetes. The relative risk in individuals having no parent with type 1 diabetes was not disclosed. Moreover, the race and ethnicity of the study populations were not disclosed.

DISCLOSURES:

The Wellcome Trust supported this study. The authors declared no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.