Leptin deficiency is a rare condition and very few cases of this disorder are reported in medical literature. The condition takes effect during the first few months after birth and eventually results in severe obesity in early childhood. Individuals affected are usually of normal birth weight, but extreme hunger causes them to gain weight quickly. If the condition is allowed to continue without treatment, it leads to hyperphagia (chronic, excessive eating patterns) which culminates in obesity. Abnormal behaviour related to eating is established in early childhood and includes fighting over food with other children, secret binging and food hoarding.
Leptin deficiency also causes hypogonadotropic hypogonadism, a condition caused by the reduction in hormones that are responsible for directing sexual development. If left untreated, the condition results in delayed puberty or individuals who skip puberty altogether, causing infertility.
Genes That Are Related to Congenital Leptin Deficiency
The function of leptin is to attach and bind to the leptin receptor protein, which fits into the receptor and acts like a key that fits into a lock, activating its function. This leptin receptor protein can be found on the cell surfaces of many organs and body tissues, including the hypothalamus (a part of the brain). The hypothalamus is the part of the brain that is responsible for controlling bodily functions such as hunger, thirst, sleep, body temperature and the control of mood. It is also responsible for regulating the release of several hormones that affect certain functions in the body. http://www.about.com/health/
When leptin binds to the leptin receptor in the hypothalamus, a series of chemical signals are triggered that affect feelings of hunger and also helps produce feelings of satiety (fullness).
This rare cause of obesity is inherited by means of an “autosomal recessive” gene pattern where both copies of a gene in each cell carry mutations. Parents of individuals with “autosomal recessive” conditions carry one copy each of the mutated gene, but do not typically present with symptoms and signs of congenital leptin deficiency disorder.
Leptin deficiency is a rare disorder which is being studied further by researchers for factors that may be involved in other, more common types of obesity.