Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a reproductive disorder characterized by an underdeveloped or absent uterus and vagina in women with a 46,XX chromosome pattern.

Overview

MRKH syndrome causes the vagina and uterus to be underdeveloped or absent. Because of this, affected women do not have menstrual periods, with the first sign often being the absence of menstruation by age 15 (primary amenorrhea). Despite these reproductive differences, affected individuals have a 46,XX chromosome pattern, normal external genitalia, functioning ovaries, and normal breast and pubic hair development.

Types and Symptoms

MRKH syndrome is divided into two types:

• Type 1: Affects only the reproductive organs.
• Type 2: Affects the reproductive organs and other parts of the body. This may include abnormally formed or positioned kidneys, unilateral renal agenesis (failure of one kidney to develop), hearing loss, heart defects, or skeletal abnormalities, particularly of the spinal bones (vertebrae).

Causes

The exact cause of MRKH syndrome is unknown. It is characterized by the incomplete development of the Müllerian duct, an embryonic structure that develops into the uterus, fallopian tubes, cervix, and the upper part of the vagina. While researchers have identified genetic changes in some affected individuals, it is unclear if these are the direct cause. Current evidence suggests that a combination of genetic and environmental factors likely contributes to the syndrome.

Inheritance

Most cases occur in individuals with no family history of the disorder. In rare instances where it is passed through families, the inheritance pattern is often unclear due to variable symptoms. In some families, it appears to follow an autosomal dominant pattern, where one copy of an altered gene is sufficient to cause the disorder.