Pallister-Hall syndrome ... (Pallister-Hall syndrome) - Gen GLI3.  

Syndrome Pallister-Hall is an alteration affecting the development of many parts of the body. Most people with this condition have polydactyly and syndactyly skin. One of the signs and symptoms of the disease include abnormal growth in the brain called the hypothalamic hamartoma. In many cases, these growths do not cause medical problems, but, however, some hypothalamic hamartoma cause seizures or hormonal abnormalities that can be life threatening in childhood. Another feature includes a malformation syndrome airway called bifida epiglottis obstruction and renal abnormalities anal orifice. Although the signs and symptoms of this disease vary from mild to severe, only a small percentage of people affected serious complications.

This process is due to mutations in the GLI3 gene, located on the short arm of chromosome 7 (7p13), encoding a protein that controls gene expression. By interacting with certain genes at specific times during development, the GLI3 protein plays a role in the development of many organs and tissues before birth. The GLI3 gene belongs to a family of genes that are involved in the normal formation of many tissues and organs during embryonic development. To perform this role, the proteins encoded by the genes of the GLI family bind to specific DNA regions and help control gene expression.

Most of the mutations responsible for Pallister-Hall syndrome occur near the middle region of the gene GLI3. These genetic changes are creating a premature stop signal in coding the GLI3 protein. As a result, cells produce an unusually short version of the protein that inactivates the expression of target genes. Although this defect clearly alters aspects of embryonic development, it is not clear how this change in the function of the protein affects development. It remains uncertain how GLI3 gene mutations can cause polydactyly, hypothalamic hamartoma, and the other features of Pallister-Hall syndrome.

Mutations in the GLI3 gene described in people with various forms of polydactyl. They are described as isolated or nonsyndromic because polydactyl occurs without other signs and symptoms, such as brain or eye abnormalities hipertelorismo. In this respect, mutations in the GLI3 gene can result in two types of Polydactyly, called polidactilia postaxial A (PAP-A) and A / B (PAP-A / B), characterized by an additional finger side of the little finger. Another way of polydactyl called preaxial polidactilia type IV (DPP-IV), may also be due to mutations in the GLI3 gene. People with this type of polidactalia have extra digits next to the thumb or big toe (hallux) and cutaneous syndactyly. In addition, PPD-IV can also include additional digits in other positions in the hands or feet. Polidactilia pattern seen in PPD-IV is similar to the cephalopolysyndactyly Greig syndrome - see cephalopolysyndactyly Greig syndrome - so it is believed that PPD-IV can be a very mild form of the syndrome.

Syndrome Pallister-Hall is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient to express the disease. In some cases, an affected person inherits a mutation in the gene GLI3 an affected parent. Other cases are due to new mutations in the gene and occur in people with no history of disease in your family.  

Tests in IVAMI: in IVAMI perform detection of mutations associated with Pallister-Hall syndrome, by complete PCR amplification of the exons of the GLI3 gene, 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).