Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome affects the reproductive system in females, causing either underdevelopment or absence of the vagina and uterus.
In the majority of cases, affected women do not have periods and a lack of menstruation by age 16 is often the first symptom of the condition.
The exact cause of MRKH syndrome is not known and most cases occur in women with no family history of the condition. Researchers suspect that both genetic and environmental factors play a role, although no genes associated with condition have yet been identified.
The reproductive defects seen in MRKH syndrome arise form abnormal development of a structure called the Mullerian duct, which develops into the upper vagina, uterus and fallopian tubes.
However, exactly what causes development of the structure to fail is unclear. Historically, researchers have suggested that the condition may arise as a result of maternal illness or fetal exposure to harmful substances such as certain medications. However, no study has yet determined an association between the syndrome and medication, illness or any other factor. Why defects in other parts of the body such as the spine and kidneys also remains unclear.
An increasing body of evidence suggests that MRKH syndrome is a genetic illness and in some cases MRKH is known to be passed on through families. However, the inheritance pattern is difficult to establish due to variable expressivity of the condition’s signs and symptoms between members of the same family.
Some research suggests that the condition does have an autosomal dominant pattern of inheritance, meaning only one altered copy of an affected gene is required for the disease to manifest.