Alpha thalassemia X - linked intectual disability syndrome ... (Alpha thalassemia X-linked syndrome intellectual disability) - Gen ATRX
The índrome s alpha thalassemia X - linked mental retardation, is a hereditary process that affects many parts of the body and occurs almost exclusively in males. Affected individuals with intellectual disabilities and developmental delays. Speech is delayed considerably, and most never talk or just a few words. Most affected children have hypotonia, delaying motor actions like sit, stand and walk, and some do not get to walk independently. Almost all people with this syndrome have distinctive facial features, including wide - set eyes, a small nose with nostrils up and low - set ears. The upper lip is shaped inverted "V", and the lower lip tends to be prominent. These facial features are more apparent in early childhood. Eventually, facial features become more apparent, including flattened face with a shorter nose. Most affected mild signs to Sanguine to a called alpha thalassemia, which reduces hemoglobin synthesis, with consequent decrease in tissue oxygenation alteration. In rare cases, affected individuals also have anemia, accompanied by paleness, weakness and fatigue. Additional features of this syndrome include microcephaly, short stature and skeletal abnormalities. Many affected individuals have Digestive problems or s, such as gastroesophageal reflux and chronic constipation. There are also frequent genital abnormalities so that affected males may have cryptorchidism and hypospadias, and in more severe cases, male and female genitalia.
This process is due to mutations in the gene ATRX, located on the long arm of the X chromosome (Xq21.1). This gene encodes a protein that plays an essential role in normal development. Although the exact function is unknown ATRX protein, it appears to help regulate the expression of other genes, in a process of chromatin remodeling. Among these genes HBA1 and HBA2 the genes that are necessary for normal hemoglobin production they are found.
They have identified more than 125 mutations in the ATRX gene in people with this syndrome. The most common mutations change the amino acids in the protein ATRX. Other mutations inserted or deleted genetic material ATRX gene. Mutations in the gene ATRX change the structure of the protein ATRX, which will probably prevent effectively regulate the expression of other genes. Reducing activity HBA1 HBA2 genes results in alpha thalassemia. L is likely to abnormal expression of other genes that have not been identified, induce developmental delay, distinctive facial features and other signs and symptoms of alpha thalassemia mental retardation syndrome X - linked
This process is inherited as a recessive X - linked pattern ATRX The gene is on the X chromosome, one of the two sex chromosomes. In males, having a only one X chromosome, an altered copy of the gene in each cell is sufficient for the process to be manifested. In females, having two X chromosomes, one normal copy of the gene ATRX generally compensates the mutated copy. Therefore, women who only have one mutated copy of the gene ATRX almost never had symptoms. A feature of the X - linked inheritance is that fathers can not pass X - linked traits to their sons chromosome.
Tests performed in IVAMI: in IVAMI perform detection of mutations associated with alpha thalassemia with mental retardation X - linked, by complete PCR amplification of exons ATRX 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).