Certain genetic abnormalities in a man’s chromosomes appear to be linked to intellectual disabilities in his offspring, especially if he fathered them late in life, a new study suggests.These abnormalities are caused by what are called “copy number variations” in genes. These include missing, repeated, inverted or misplaced DNA sequences, the researchers explained. “While it is commonly known that the risk of birth defects such as Down Syndrome increases with maternal age, this study shows that an increased paternal age is also an important factor,” said study author Jayne Hehir-Kwa, from the department of human genetics at the University of Nijmegen in the Netherlands.
