Autopsies and genetic tests conducted on aborted foetuses in a city hospital during a 11-year study, found that nearly 63 per cent of the foetuses had anomalies due to genetic reasons.
Published recently in the Journal of Fetal Medicine, the study was on pregnancies which were terminated within 12-30 weeks atSir Ganga Ram hospital after malformations were observed in limb formations during ultrasounds.
The study found that in 62.7 per cent cases, the anomalies were due to genetics. Of this, 25.4 per cent cases were due to chromosomal disorders.
Senior consultant in genetic medicine at the hospital, Dr Ratna Puri, said, “Improved imaging technologies led to increased detection rates of anomalies in limb formations of the foetus. These anomalies are not life-threatening and can be surgically corrected. But,they may be the first indication of underlying genetic disorders. So, despite knowing that the physical malformation in their child may be surgically corrected, many couples opt for termination of pregnancy due to uncertainty of the diagnosis and the socio-economic burden of a handicapped child.”
However, after termination of pregnancies, autopsies and genetic evaluation are rarely performed, she said.
“As a result, we were missing the opportunity to diagnose genetic disorders. So we decided to examine the utility of foetal autopsy and determine the incidence of genetic disorders in cases which were aborted for these malformations. We found that nearly 63 per cent did have genetic disorders,” Dr Puri said.
Doctors studied only foetuses which were aborted for limb malformations because these are very prominent in ultrasounds. Autopsies of foetuses aborted between 12 weeks to 30 weeks — with a mean of 17.5 weeks — from April 2003 till June 2014 were studied.
Besides physical examination during autopsies, ultrasound records were studied and chromosomal tests were conducted. DNA was extracted from the placenta or fetal spleen and stored in all the cases, doctors said.
To study genetic history, three generations of genetic information was collected from families and a history of illnesses of the mothers were taken. In 61 per cent of the findings, doctors found that the autopsy revealed exactly the same findings as seen in the pre-natal ultrasounds. In 23.7 per cent cases, additional anomalies were observed — the commonest being orofacial clefts, where the right and lift part of the lip was not joined properly.
“We observed that most of the identifiable genetic disorders were present in cases with multiple limb anomalies. Only five cases with single anomalies were included, and no specific genetic condition could be diagnosed in this group. So, this study presents strong evidence to consider foetal autopsy, and genetic disorders in all cases with limb anomalies…” Dr Puri said.
Dr U H Kotecha, corresponding author of the study, said, “Out of 59 cases, maternal risk factors were present in four cases. Four families previously had a similar affected baby, thus indicating a high probability of a genetic association.”
In 28 cases, ultrasound findings showed that the anomaly was limited to the lower limbs. Upper limbs were affected in 14 cases while both limbs were involved in 17 cases. Limb defects were present along with other malformations in 44 cases. In the 62 per cent cases which were found to have genetic associations, “recognisable genetic syndromes/sequences” were observed in 59.4 per cent.
In 11 out of 44 foetuses with multiple defects, “no definitive conclusions regarding etiology were made”, the study noted. Doctors have also said while there were no false positives — no anomalies revealed in autopsies where the ultrasound confirmed them — they said, “a better delineation of the limb defect was possible only after termination in three cases.”