PESHAWAR: Standing outside his house with his two blind children in Charsadda's Mian Kalay village, Zahirullah Khan's grief is inconsolable. "Two of my other children also died after reaching puberty," says the tearful father.

For the past 40 years, almost every third home in the village, which is situated some 30 kilometres south of Peshawar, has children suffering from birth defects.

Disabilities range from blindness, cerebral palsy, mental disorders, thalassemia, physical deformities and hearing and speech impairments to name a few.

Doctors have termed generations of inter-family marriages in the village — which has 350 households — as the main cause behind birth defects in children. There are two major tribes in the village, Miya and Shpon, and unions between men and women from solely these two clans is the ongoing tradition.

Dr Muhammad Ali, a District Health Officer (DHO) at Charsadda's district hospital, says that first-cousin marriages result in children with genetic disorders. "Birth defects due to inter-family marriages is not just prevalent in Mian Kalay; this can happen anywhere in the world where there is inbreeding."

While residents are aware that off-spring of inter-family marriages are likely to have birth defects or disabilities, they continue with the practice due to cultural norms.

A local journalist in Charsadda, Muhammad Tayeb, says all the men in the village belong to either of the two aforesaid tribes, and cannot marry other girls due to cultural restrictions.

Born as a flaccid baby, Salma Bibi, 36, is the mentally-challenged daughter of Mohammad Gul. Her father says they cannot let her walk independently in the house as she is too weak to control her movements.

Despite trying their utmost to get Salma treated, her condition remains the same. “Such genetic disorders in children are life-long and hard to be treated,” says Dr Kashif Ali Khan of Peshawar's Lady Reading Hospital.

Her father also acknowledges that the increased prevalence of birth defects and deformities in Mian Kalay is due to children born out of consanguineous marriages.

"Inbreeding can cause problems in first, second and even third generation offspring," says Dr Ali.

The doctor discounts suggestions that environmental factors contribute to the birth defects and deformities, saying that a poor environment is indicated by conditions like diarrhoea and fluid build-up in infants, which has not been seen among the children of Mian Kalay.

However, he does cite prolonged and delayed labor at the time of pregnancies as another reason for birth defects in children. "Whenever a delay occurs at the time of pregnancies due to lack of proper labour services, there is high likelihood of birth defects in newborns.”

A study titled "Key factors in understanding differences in rates of birth defects identified" jointly carried out by Universities of Bradford and Leeds says that in Pakistan, 77 per cent of babies born with birth defects were to parents who were in consanguineous marriages.

Quoting the National Coalition for Health and Professional Education, Dr Kashif Ali Khan, a medical officer at the paediatric unit of LRH, says children born to first-cousin parents have a 5.1 – 11.2pc risk of serious birth defects as compared to the general population risk of 3-4pc. He adds that an estimated 80-90% of marriages in the Charsadda village area are consanguineous.

Dr Khan says pre-existing defects in a child such as hypoplastic heart (a condition where the child's left ventricle is underdeveloped), agenesis of kidney (a defect where a child's one or both kidney(s) fail after few years of birth), blindness and neurodegenerative conditions also lead to deformities.

He further says that iodine deficiency in parents can also cause defects in new-borns. "Children born to couples who have low levels of iodine would be flaccid and weak."

"When to-be mothers have a deficiency of iodine, they make up for it by taking thyroid medication. Effects of such medications impact the baby in the womb. Following birth, the baby may be at risk of developing birth defects because either the medication may stop or the infant does not have the capacity to take it on his/her own."

Asked why there was low level of iodine in expectant mothers, he says a team of health experts would have to investigate the food, water, salt and other living standards of the village in order to determine the cause.

“The probe will lead to proper diagnosis of the cause of iodine deficiency.”

In the meantime, he suggests that 'torch test' can be performed on couples to screen for deficiencies that can result in potential birth defects, following which preventive measures can be taken before conceiving.