Multiple epiphyseal dysplasia

Multiple epiphyseal dysplasia (MED) may be inherited in an autosomal dominant or autosomal recessive manner depending on the genetic cause. Most cases are autosomal dominant.^[1] In autosomal dominant inheritance, having a mutation in only one of the 2 copies of the responsible gene is enough to cause the condition. The mutation may be inherited from a parent or can occur for the first time in the affected person. Each child of a person with an autosomal dominant condition has a 50% (1 in 2) chance to inherit the mutation.

More rarely, MED is inherited in an autosomal recessive manner. In autosomal recessive inheritance, a person must have a mutation in both copies of the responsible gene to be affected. The parents of a person with an autosomal recessive condition usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not have signs or symptoms and are unaffected. When two carriers for the same condition have children, each child has a 25% (1 in 4) chance to be affected, a 50% (1 in 2) chance to be a carrier like each parent, and a 25% to be both unaffected and not a carrier.

The risk for an individual with MED to pass the condition on to his/her offspring depends on the type of MED the individual has. Each child of an individual with an autosomal dominant form of MED has a 50% (1 in 2) risk to inherit the condition. In order for an individual with an autosomal recessive form of MED to have a child with the condition, that individual's partner must be a carrier for the same form of MED (e.g. he/she must have a mutation in the same disease-causing gene). Genetic testing may help to confirm the type of MED an individual has, as well as whether a partner is a carrier.

Individuals who are interested in learning more about the genetics of MED, genetic testing for MED and/or the genetic risks to themselves or family members should speak with a genetics professional.

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

A search of the available medical literature does not yield information about an association between autosomal dominant MED and cleft palate. Cleft palate is a congenital abnormality (present at birth). The autosomal dominant form of multiple epiphyseal dysplasia (MED) typically manifests late in childhood. At birth, the affected individual's external appearance is normal, and clinical features of MED are seen in late childhood.^[2]

About 50 percent of individuals with autosomal recessive multiple epiphyseal dysplasia are born with at least one abnormal feature, which may include cleft palate; clubfoot; an unusual curving of the fingers or toes (clinodactyly); ear swelling; and/or an abnormality of the kneecap called a double-layered patella.^[1]

Although cleft palate may occur as part of some syndromes, there are many causes of this birth defect. In addition to genetic abnormalities, cleft palate may be caused by other things such as fetal exposure to drugs, viruses or other toxins.^[3] About 6,800 babies in the United States are born with oral clefts each year. Nearly 2,600 babies are born with isolated cleft palate (occurring with no other abnormalities) each year.^[4]