3p deletion syndrome ... (3p deletion syndrome) - chromosome 3
3p deletion syndrome is a process that develops due to a chromosomal rearrangement in which a small segment of chromosome 3 in each cell is removed. The deletion occurs at the end of the short arm of chromosome. Often this chromosomal change causes mental retardation, developmental delay and abnormal physical characteristics.
In general, individuals with 3p deletion syndrome have severe to profound intellectual disabilities. Most show a delay in the development of language and motor skills. While affected individuals learn to walk in childhood, language ability usually remains limited. Some individuals with 3p deletion syndrome have Obsessive Compulsive Disorder (OCD) or characteristics of autism spectrum disorders. Physical signs and symptoms of 3p deletion syndrome vary greatly. Many affected individuals have slow growth, microcephaly, micrognathia, ptosis, malformed ears or nose and hypertelorism. Other common features include skin folds covering the inner angle of the eye in epicanto, Polydactyly and an opening on the palate. In addition, individuals with 3p deletion syndrome may suffer seizures, hypotonia, cardiac intestinal disorders and birth defects.
The size of the deletion responsible for this process varies among affected individuals, from about 150 kb to 11 Mb. The deletion may include between 4 and 71 known genes. In some individuals, it involves removing material near the end of the chromosome, but does not include the telomere. Signs and symptoms associated with 3p deletion syndrome result from the loss of 3p genes in the region. It is difficult to determine which genes may be responsible for the specific characteristics due to variability in both the size of the deletion, as in signs and symptoms of the disease among affected individuals. Multiple genes at the end of chromosome 3 appear to play a role in neurological development, but because not all people with 3p deletion syndrome are missing the same genes, it is difficult to determine what influence cognitive symptoms. It is likely that loss of multiple genes contributing to the different physical anomalies.
Most cases of 3p deletion syndrome is not inherited. The deletion occurs on a chromosome more often as a random event during the formation of reproductive cells or early embryonic development. In these cases, the affected people have no history of the disease in his family. In rare cases, this process can be hereditary, usually of a mild affected parent form. The deletion can also be inherited from an affected parent carries a balanced translocation. Balanced translocation any genetic material is gained or lost, so these chromosomal changes usually do not cause any health problems. However, translocations may become unbalanced as they are transmitted to the next generation. Children who inherit an unbalanced translocation chromosome rearrangement have extra or missing genetic material. Individuals with 3p deletion syndrome associated with an unbalanced translocation have no genetic material from the short arm of chromosome 3, which leads to the signs and symptoms of this process.
Tests in IVAMI: in IVAMI perform detection of mutations associated with 3p deletion syndrome by a method of quantitative PCR amplification in real time.
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).