Phocomelia is a form of birth defect in which the long bones in one or more limbs are missing or shortened. As a result, the entire limb is foreshortened. The limb may appear flipperlike, explaining the name, which is derived from the root words for “seal” and “limb.” This birth defect is quite rare. Children born with this condition may require surgery to address other abnormalities which sometimes occur concurrently with phocomelia.
There are several ways in which phocomelia may develop in utero. One is a spontaneous genetic mutation, usually triggered by environmental pressures. Notoriously, the drug thalidomide which was once prescribed to pregnant women can cause phocomelia, and some people refer to this condition as “pseudo-thalidomide” in a reference to this. Once people stopped prescribing this medication to pregnant women, the incidence of phocomelia went down dramatically.
This condition can also be inherited. Families may carry recessive genes for phocomelia which get passed on to a child who can, in turn, develop the condition. Having one of more foreshortened limbs does not necessarily mean that one will pass the trait on, or that the trait will manifest in exactly the same way in a child. Genetics can be very complicated, and the interactions of several recessive genes can be involved in the expression of phocomelia. People who are concerned can talk to a genetic counselor about the specifics of their case and their concerns.
In addition to the shortened limbs, the condition can also be associated with defects in the heart, kidneys, or uterus. Abnormalities with the skull can also appear, and some people experience facial palsy, scoliosis, and other issues in conjunction with phocomelia. Some of these conditions may be diagnosed at birth, while others may be uncovered later in life, and they may require treatments such as reconstructive surgery. The condition can also appear with amelia, in which a limb is entirely absent.
Individuals with phocomelia may need some accommodations; for example, someone with a shortened limb might need special controls for a car in order to drive safely, and accommodations such as devices to hold things in place can be useful for people with shortened arms. An occupational therapist can work with someone who has phocomelia to discuss potentially useful accommodations and modifications which will allow the person to navigate a world which has been designed for people who have full use of all four limbs.