To try and understand the basic genetics of club foot and find any genes that may be responsible, researchers from the Washington University School of Medicine in St. Louis studied several generations of one family. They studied the DNA of 35 family members of a patient of one of the researchers. This particular patient is a child with clubfoot in both feet.
The scientists examined the lower limbs of the relatives and took DNA samples. 13 family members were affected. When their DNA was analysed the researchers found a region on chromosome 5 that was common to all those affected. Further investigation revealed that there was a mutation on the PITX1 gene. It's this genetic mutation that scientists believe contributes to clubfoot. The genetic mutation was also present in 3 members who were carriers for clubfoot. They did not have the condition themselves.
Previous studies have linked the gene with hind limb development in other vertebrates. In mice for example a loss of PITX1 results in shorter femur length and fewer digits on the right foot.
The discovery of at least one gene was welcome news to scientists. This is echoed by one of the authors of the study, Christina Gurnett, M.D., Ph.D., assistant professor of neurology, of pediatrics and of orthopedic surgery at the School of Medicine. "Until now, we didn't know whether clubfoot was a muscle, nerve, spinal cord or brain problem. Now, we have an idea that clubfoot may result from mutations of genes that are involved in early limb development."
