Intellectual Disability Tied to Father Being Older at Conception

Introduction

Faulty intellectual disability genes linked to older dads at conception. Chromosomal abnormalities linked to intellectual disability can be traced back to the father, particularly those who are older when the child is conceived, finds research published online in the Journal of Medical Genetics.

Main Digest

Chromosomal abnormalities are caused by copy number variations or CNVs. These structural variations result in missing, repeated, inverted, or misplaced DNA sequences in cells. Copy number variations can be inherited or arise anew and are a common cause of disease. However, little is known about how CNVs are formed, for example, if they occur more frequently on the DNA sequence passed on by the mother or the father or if parental age is important.

The research team systematically analyzed the prevalence of rare CNVs in almost 3500 people with intellectual disabilities between 2006 and 2010. They found CNVs that had arisen anew, as opposed to being inherited, in 227 people, meaning the prevalence was around twice as common in this group as among people with autism and three times as common as among those with asthma.

Further analysis to determine the parental origin of the CNVs in the 118 people for whom data were available showed that 90 had come from the father and that three-quarters represented missing DNA sequences.

The researchers compared the father's age at the time of birth in the group with CNVs with people with no intellectual disability, matching for ethnicity and era of birth to minimize the impact of any cultural or social factors. But they found no differences in paternal age between the two groups.

The researchers then divided people with CNVs into two groups:

• Those with CNVs occurring in regions of the genome with highly repetitive DNA sequences.
• Those with CNVs occurring in non - repetitive DNA sequences.

They also compared paternal ages in both groups with those of the people without any intellectual disability.

A significant increase in the father's age was found in the group of CNVs in non-repetitive DNA sequences - which accounted for most CNVs - providing crucial insight into understanding how and why disease-causing CNVs are formed, say the authors.

The findings also indicate that newly arising CNVs not only originate more often from the father's DNA but that the father's age has a role, the authors add.

"In conclusion, our data provide for the first time convincing evidence that CNVs in intellectual disability are largely paternal in origin," they write.

They suggest that ongoing cell divisions of self can explain both the gender and age bias - renewing sperm cells during the fetal development of boys - with the potential for mistakes - as well as impaired DNA genesis and repair as a consequence of the aging process.

Attribution/Source(s):

This quality-reviewed publication was selected for publishing by the editors of Disabled World due to its significant relevance to the disability community. Originally authored by British Medical Journal (BMJ), and published on 2011/10/13 (Edit Update: 2022/06/20), the content may have been edited for style, clarity, or brevity. For further details or clarifications, British Medical Journal (BMJ) can be contacted at bmj.com. NOTE: Disabled World does not provide any warranties or endorsements related to this article.

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Cite This Page (APA): British Medical Journal (BMJ). (2011, October 13 - Last revised: 2022, June 20). Intellectual Disability Tied to Father Being Older at Conception. Disabled World. Retrieved September 14, 2024 from www.disabled-world.com/disability/types/cognitive/conception-age.php

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