Renpenning syndrome ... (Renpenning syndrome) - Gen PQBP1
Renpenning syndrome is a process that affects almost exclusively males, characterized by developmental delay, moderate to severe mental retardation and distinct physical characteristics.
Individuals with Renpenning syndrome usually have short stature; microcephaly; facial features including a long, narrow face, palpebral fissures up, a long, bulbous nose with columela, philtrum and cup - shaped ears; small testes in males; and seizures and atrophy of skeletal muscles. About 20 percent of individuals with Renpenning syndrome also have other characteristics that may include coloboma, cleft palate, cardiac abnormalities or defects of the anus.
Often, certain combinations of features that occur in Renpenning syndrome are sometimes called by other names, such as Golabi-Ito-Hall syndrome or syndrome Sutherland-Haan. However, all these syndromes, which have the same genetic cause, are grouped under the term Renpenning syndrome.
This process is due to alterations in the gene sequence PQBP1 (polyglutamine binding protein 1), located on the short arm of chromosome X (Xp11.23) encoding polyglutamine binding protein 1. This protein binds to ecuencias of sections multiple copies of the amino acid glutamine in other proteins. Although the specific function of the protein binding polyglutamine 1 is not well understood, it is believed to play a role in processing and RNA transport. In neurons, such as brain, polyglutamine binding protein 1 is in granules RNA. These granules permit transport and storage of RNA inside the cell. RNA is carried out inside the granules until the genetic information carried translates to encode proteins or until the cellular signals or environmental factors that trigger the RNA degradation. Through these mechanisms, it is believed that the protein binding polyglutamine 1 helps to control gene expression in neurons. This control is important for normal brain development.
They have been described at least 14 mutations in the gene PQBP1 in people with Renpenning syndrome. Most of these genetic mutations result in an abnormally short polyglutamine protein 1 with altered function, which probably interferes with normal gene expression in neurons. As a result, abnormal brain development and the signs and symptoms of Renpenning syndrome occurs.
The Renpenning syndrome is inherited with a recessive X - linked pattern in males, who have only one X chromosome, an altered copy of the gene in each cell it is sufficient to express the disease. In females, having two X chromosomes, a mutation must occur in both copies of the gene for the disease is expressed. Because it is unlikely that women have two altered copies of this gene, males are affected by recessive X - linked disorders much more frequently than women. A feature of the X - linked inheritance is that fathers can not pass X - linked traits to their sons chromosome.
Tests in IVAMI: in IVAMI perform detection of mutations associated with Renpenning syndrome, by complete PCR amplification of exons PQBP1 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).