HARLEQUINA ichthyosis (Harlequin ichthyosis) - Gen ABCA12.
The HARLEQUINA ichthyosis is a serious genetic disease that primarily affects the skin. Children with this disorder are born with very hard, thick skin covering most of his body. The skin forms large plates, diamond - shaped are separated by fissures. These skin abnormalities affect the shape of the eyelids, nose, mouth and ears, and limit the movement of arms and legs. The restricted movement of the chest can cause difficulty breathing and respiratory failure.
Typically skin forms a protective barrier between the organism and its surrounding environment. The skin abnormalities associated with HARLEQUINA ichthyosis disrupt this barrier, making it difficult for children affected water loss control, regulating body temperature and fight infections. For this reason, affected children often manifest dehydration and develop life - threatening infections in the first weeks. Used to be very rare for children affected would survive the neonatal period. However, with intensive medical support and improved treatment, people affected now have increased life expectancy in childhood and adolescence.
This process is due to changes in the ABCA12 gene, located on the long arm of chromosome 2 (q34). This gene encodes a carrier protein known as ATP binding cassette (ABC). ABC transport proteins carry many types of molecules across cell membranes. In particular, ABCA12 protein plays an important role in lipid transport in the cells that form the epidermis. This lipid transport appears to be essential for normal skin development. The ABCA12 protein is also found in other tissues, including testis, placenta, lung, stomach and brain and liver fetal.
Several mutations have been identified in the ABCA12 gene in people with ichthyosis HARLEQUINA. Most of these mutations probably lead to an absence of ABCA12 or coding an extremely small protein that transport lipids can not properly release protein. Lack of transport of lipids causes numerous problems with the development of the epidermis before and after birth. Specifically inhibit skin formation of an effective barrier against dehydration and infection, and leads to the formation of thick and hard scale features of the disease.
This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with ichthyosis HARLEQUINA, by complete PCR amplification of the exons of the gene ABCA12, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).