Paired-like homeobox 2b (PHOX2B), also known as neuroblastoma Phox (NBPhox), is a protein that in humans is encoded by the PHOX2B gene located on chromosome 4. [5]
It codes for a homeodomain transcription factor. It is expressed exclusively in the nervous system, in most neurons that control the viscera (cardiovascular, digestive and respiratory systems). It is also required for their differentiation.
Essential for the differentiation and survival of sympathetic neurons and chromaffin cells, the transcription factor PHOX2B is highly specific for the peripheral autonomic nervous system. Neuroblasts are derived from sympathoadrenal lineage neural crest cells and therefore require and constitutively express PHOX2B. PHOX2B immunohistochemical staining, as a marker of neural crest derivation, has been shown to be sensitive and specific for undifferentiated neuroblastoma, enabling identification where other markers fail to recognize neuroblastoma among various different small round blue cell tumors of childhood. [6] [7] [8] [9]
The diagnostic utility of PHOX2B staining extends to later stages of differentiation. Its strength and specificity can detect the small foci of neuroblastic tumors metastatic to the bone marrow, an identification critical for determining disease staging. PHOX2B staining also overcomes frequent obstacles to neuroblastoma detection in post-treatment samples, which frequently exhibit dense fibrosis, prominent inflammatory infiltrates, and/or diffuse calcification. [10]
Mutations in human PHOX2B cause a rare disease of the visceral nervous system (dysautonomia): congenital central hypoventilation syndrome (associated with respiratory arrests during sleep and, occasionally, wakefulness), Hirschsprung's disease (partial agenesis of the enteric nervous system), ROHHAD, and tumours of the sympathetic ganglia. In most people, Exon 3 of the gene contains a sequence of 20 polyalanine repeats. An increase in the number of repeats is associated with congenital central hypoventilation syndrome. There may also be other pathogenic mutations further along the gene.
Central Hypoventilation Syndrome (CHS) is a sleep-related breathing disorder that causes ineffective breathing, apnea, or respiratory arrest during sleep. CHS can either be congenital (CCHS) or acquired (ACHS) later in life. The condition can be fatal if untreated. CCHS was once known as Ondine's curse.
Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial (SDHB) also known as iron-sulfur subunit of complex II (Ip) is a protein that in humans is encoded by the SDHB gene.
Inositol polyphosphate 5-phosphatase OCRL-1, also known as Lowe oculocerebrorenal syndrome protein, is an enzyme encoded by the OCRL gene located on the X chromosome in humans.
LIM homeobox transcription factor 1-beta, also known as LMX1B, is a protein which in humans is encoded by the LMX1B gene.
Fukutin is a eukaryotic protein necessary for the maintenance of muscle integrity, cortical histogenesis, and normal ocular development. Mutations in the fukutin gene have been shown to result in Fukuyama congenital muscular dystrophy (FCMD) characterised by brain malformation - one of the most common autosomal-recessive disorders in Japan. In humans this protein is encoded by the FCMD gene, located on chromosome 9q31. Human fukutin exhibits a length of 461 amino acids and a predicted molecular mass of 53.7 kDa.
Cell division cycle 73, Paf1/RNA polymerase II complex component, homolog , also known as CDC73 and parafibromin, is a protein which in humans is encoded by the CDC73 gene.
Gap junction alpha-5 protein (GJA5), also known as connexin 40 (Cx40) — is a protein that in humans is encoded by the GJA5 gene.
Protein patched homolog 1 is a protein that is the member of the patched family and in humans is encoded by the PTCH1 gene.
Wolframin is a protein that in humans is encoded by the WFS1 gene.
Endothelin-3 is a protein that in humans is encoded by the EDN3 gene.
Acetylcholine receptor subunit epsilon is a protein that in humans is encoded by the CHRNE gene.
Phosphorylase b kinase regulatory subunit alpha, liver isoform is an enzyme that in humans is encoded by the PHKA2 gene.
Achaete-scute homolog 1 is a protein that in humans is encoded by the ASCL1 gene. Because it was discovered subsequent to studies on its homolog in Drosophila, the Achaete-scute complex, it was originally named MASH-1 for mammalian achaete scute homolog-1.
Paired mesoderm homeobox protein 2A is a protein that in humans is encoded by the PHOX2A gene.
Centrosomal protein of 290 kDa is a protein that in humans is encoded by the CEP290 gene. CEP290 is located on the Q arm of chromosome 12.
Dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase is an enzyme that, in humans, is encoded by the ALG3 gene.
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited disorder.
Forkhead box protein E3 (FOXE3) also known as forkhead-related transcription factor 8 (FREAC-8) is a protein that in humans is encoded by the FOXE3 gene located on the short arm of chromosome 1.
Stanislas Lyonnet is a French geneticist. As of 2012 he was Professor of genetics at Paris Descartes University, and a clinical geneticist in the Department of Medical Genetics at the Hôpital Necker - Enfants Malades. His research is aimed at isolating the genes that cause congenital malformation and birth defects.
Cripto, FRL-1, cryptic family 1 is a protein that in humans is encoded by the CFC1 gene.
 | This article on a gene on human chromosome 4 is a stub. You can help Wikipedia by expanding it. |
