Inherited genetic factors behind variation in adult heights: study

New Delhi: While the normal variation in adult height is primarily due to inherited genetic factors, at the extreme of short stature, patients often have mutations in a single gene, resulting in a large effect on their height, a study has revealed.

Sir Ganga Ram hospital conducted the study, subjecting 455 patients with short stature. Among them, 226 patients required detailed phenotyping and genetic testing for confirmation of aetiology, while 229 were identified on preliminary history/ examination and investigations, IANS reported.

The study of 455 individuals, 10 months to 16 years of age, has been published in 'Indian Pediatrics'. All of these individuals had a height less than 3rd centile (only less than 3 out of 100 are shorter than this child).

The study, published in "India Pediatrics", had an age range of the subjects from 10 months to 16 years. All of these individuals had a height less than 3rd centile (less than 3 out of 100 are shorter than this child). The study found that 63 per cent (142) had proportionate short stature (upper and lower parts are equally short abnormally. Out of the 142, 93 (65 per cent) ) had recognisable genetic syndromes such as Turner Syndrome, William Syndrome, RASopathies, etc.

"Genetics plays an important part in determining an individual's height. Although there are many monogenic disorders, inherited diseases controlled by a fault in a single gene, that lead to perturbations in growth and result in short stature, this study asserts the importance of good clinical examination to enable correct diagnosis," said Dr Ratna Dua Puri, Chairperson of the Institute of Medical Genetics and Genomics at Sir Ganga Ram Hospital.

Puri added that they wish to reiterate that amongst the armamentarium of genetic tests available, a clinical profile assessment enables a diagnosis in 65 per cent of patients with proportionate short stature. Additionally, the tests to be offered would depend on the clinical profile.

In clinically undefined syndromes, out of 226,39 (27 per cent), a diagnosis could be made by Karyotype, Chromosomal Microarray, and Exome Sequencing.

Balance of 84 children (37 per cent) had disproportionate short stature, either upper or lower part of the body is short, 38 (45 per cent) children had Lysosomal Storage Disorder which was identified by Enzyme Analysis among 86.8 per cent individuals. Skeletal Dysplasias, found in 37 (44 per cent) individuals, were identified by Skeletal Survey among 89 per cent of cases, and unclassified were 9 (8 per cent).

"Through this study, we have attempted to represent the genetic spectrum of disorders in children with short stature and the appropriate testing indications. This becomes more relevant with the increasing ability of the tests and decreasing costs", Dr Puri said.