Shorter height linked to shortage of genes

Missing factor

Researchers found that missing copies of genes or other sections of DNA is associated with half of the genetic impact on our height, the Daily Telegraph reported.

The genetic abnormalities, known as copy number variants (CNV), are alterations within the chromosome that means a cell has either too many or too few copies of a slice of DNA, the acid which contains our genetic code, the researchers said.

In some places this might relate to a connection within the chromosome, but in others part or a whole copy of one or more genes might be either missing or duplicated. Some CNVs are common but others only occur in a small number of people.

The researchers found that people with more unusual CNV deletions — where part of the genome is missing — have a tendency to be shorter in stature.

While everyone has at least some of these deletions in their genome, covering thousands of individual components of DNA, others have several million.

Two studies of a combined 12,000 people by a team led by researchers from the Children’s Hospital Boston found that for every million individual deletions, people lost one eighth of an inch in height.

Dr Joel Hirschhorn, who led the study, said it showed a small but firm link between the amount of genetic material missing and a decrease in height. This trend stood up regardless of which genes were missing, he added.

“Each deletion takes out some letters of the DNA sequence — most have no effect but some have a modest effect. With both areas that have an effect on height and those that do not, we found a small relationship between deletions and short stature,” he said.
The new study was published in the American Journal of Human Genetics.