Lack of genes linked to shorter height

People with short stature may actually be missing out on certain specific genes, a new study has revealed. New research sifted through the entire genome of thousands of human subjects to look for genetic variation associated with height. The results of the study suggested that excess number of uncommon genetic deletions is associated with short height of the people. Height is a highly heritable trait that is associated with variation in many different genes. "Despite tremendous recent progress in finding common genetic variants associated with height, thus far these variants only explain about 10 per cent of the variation in adult height," said senior study author, Dr. Joel N Hirschhorn, from Children's Hospital Boston and the Broad Institute. "It has been estimated that about half of height variation could eventually be accounted for by the sorts of variants we've been looking at, so it is possible that other types of genetic variants, such as copy number variants (CNVs), may also contribute to the genetic variation in stature." Dr. Hirschhorn, co-authors Dr. Yiping Shen and Dr. Andrew Dauber, and their colleagues looked for associations of human stature with CNVs, something that has not been done before. A CNV is excess (gain) in genetic material or an absence (deletion) of parts of the genome. Some CNVs are common, meaning that they are observed often in the human genome. Other CNVs are rare or occur with low frequency in the human population. "To investigate whether CNVs play a role in short or tall stature, we conducted a genome-wide association study of copy number in a cohort of children who had comparative genomic hybridization microarray screening for clinical reasons and we observed an excess of rare deletions in children with short stature," said Dr. Shen. "We extended our findings to a large population-based cohort, and again observed an excess of low frequency deletions in shorter individuals." The findings were not due to known gene deletion syndromes and no significant associations were observed between CNV and tall stature. "Our findings strongly support the hypothesis that increasing burden of lower frequency deletions can lead to shorter stature, and suggest that this phenomenon extends to the general population," said Dr. Dauber. The study has been published in the American Journal of Human Genetics.