Study says inherited genetic variables play a substantial role in adult height variation

The normal variation in adult height is largely due to inherited genetic factors. But, by contrast, at the extreme of short stature, patients often have mutations in a single gene, resulting in a large effect on their height, said a study.

The study, conducted by Sir Ganga Ram Hospital, was carried out on 455 patients with short stature, and of them, 226 patients required detailed phenotyping and genetic testing for confirmation of etiology while 229 were identified on preliminary history/ examination and investigations.

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

As per the study, 63 percent (142) had proportionate short stature (upper and lower parts are equally short abnormally). Of these, 93 (65 percent) had recognizable 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.

Dr. Puri added that they wanted to reiterate that amongst the armamentarium of genetic tests available, a clinical profile assessment enables a diagnosis in 65 percent 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 percent), a diagnosis could be made by Karyotype, Chromosomal Microarray, and Exome Sequencing.

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

"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. (AA/IANS)