MKRN3 Gene

Central precocious puberty is a condition that causes early sexual development in girls and boys. While puberty normally starts between ages 8 and 13 in girls and between ages 9 and 14 in boys, girls with central precocious puberty begin exhibiting signs before age 8, and boys with this disorder begin before age 9. Signs of puberty include development of pubic and underarm hair, a rapid increase in height (commonly referred to as a "growth spurt"), acne, and underarm odor. Girls also develop breasts and begin their menstrual periods. Boys have growth of the penis and testes and deepening of the voice. Because of the early growth spurt, children with central precocious puberty may be taller than their peers; however, they may stop growing abnormally early. Without proper treatment, some affected individuals are shorter in adulthood compared with other members of their family. Developing ahead of their peers can be emotionally difficult for affected individuals and may lead to psychological and behavioral problems.

Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes (the most common form of diabetes).

People with Prader-Willi syndrome typically have mild to moderate intellectual impairment and learning disabilities. Behavioral problems are common, including temper outbursts, stubbornness, and compulsive behavior such as picking at the skin. Sleep abnormalities can also occur. Additional features of this condition include distinctive facial features such as a narrow forehead, almond-shaped eyes, and a triangular mouth; short stature; and small hands and feet. Some people with Prader-Willi syndrome have unusually fair skin and light-colored hair. Both affected males and affected females have underdeveloped genitals. Puberty is delayed or incomplete, and most affected individuals are unable to have children (infertile).