Hereditary Split-hand and Split-foot in a family

Hereditary Split-Hand and Split-Foot in a Family

A family from an Andhra district visited us for genetic counselling with their 1-year-old baby boy. His hands were covered in mittens and feet in yellow socks — hiding two fused fingers on the right hand and only two large toes on both feet, a condition commonly referred to as Split Hand/Foot. He was unable to walk properly because of his feet. They had a positive family history (affected niece and nephew), were informed of its hereditary nature, and believed every future child would have the same condition. Luckily, a paediatrician referred them to MapmyGenome for genetic counselling.

Two Major Misconceptions

1. Assuming a 100% recurrence risk, they had planned on not having any more children

2. They thought their baby’s mental development would be affected

It is extremely common for families to have misinformation about the nature, cause, or recurrence of a genetic condition — and this is often a source of parental anxiety and distress. Genetic counselling is aimed at addressing exactly these concerns.

What Genetic Counselling Revealed

Nature of the condition: Split Hand/Foot is not progressive and does not affect multiple organs or mental development. The couple was reassured that the baby would most likely have normal physical and mental development and be able to lead a reasonably normal life. Plastic surgery and special shoes would help with appearance and mobility.

Cause: Genetic testing in the baby revealed a change in both copies of the WNT10B gene. Confirming a genetic cause is crucial not only for appropriate clinical management, but also to provide accurate recurrence risk to the couple and other at-risk family members.

Recurrence risk: Since genetic testing revealed a homozygous mutation in the son, it meant both parents were obligate, unaffected carriers (carrying the mutation in a single copy of the gene). This revised their perceived risk from 100% to 25% (1 in 4 chance) — and changed their minds about not having another baby.

The Importance of Genetic Counselling

Not every village, district, or state in India has an expert in genetics. A referral to genetic counselling can be life-changing for several families. This family was able to have their misinformation corrected, concerns addressed, and be helped and empowered. A recommendation for prenatal testing during a future pregnancy was made, and a detailed summary letter with recommendations was sent to the referring paediatrician.

By Dr. Risha Nahar Lulla, MSc (Glasgow), PhD (Delhi), Board-Certified Senior Genetic Counsellor, MapmyGenome