Chuvash polycythemia is a rare congenital form of polycythemia caused by homozygous R200W and H191D mutations in the VHL (von Hippel-Lindau) gene, whose gene product is the principal negative regulator of hypoxia-inducible factor.
However, now we describe a new homozygous VHL exon 2 mutation of the VHL gene:(c.413C>T):P138L, which is associated in the affected homozygote with congenital polycythemia but not in her, or her-heterozygous relatives, with cancer or other VHL syndrome tumors.
We report on five Caucasian patients with congenital polycythemia and mutations of the von Hipple-Lindau (VHL) gene: a compound heterozygote for the novel exon 1 (VHL 235C->T) and previously reported VHL 562C->G mutations; three homozygotes for Chuvash VHL 598C->T mutation; and a heterozygote for VHL 523->G mutation who also has ataxia-telangiectasia; a rare autosomal disease of childhood onset.
Mutations in the von Hippel-Lindau (VHL) gene are pathogenic in VHL disease, congenital polycythaemia and clear cell renal carcinoma (ccRCC). pVHL forms a ternary complex with elongin C and elongin B, critical for pVHL stability and function, which interacts with Cullin-2 and RING-box protein 1 to target hypoxia-inducible factor for polyubiquitination and proteasomal degradation.
This observation contrasts with a report suggesting that polycythemia in VHLR200W and H191D homozygotes is due to the loss of JAK2 regulation from VHLR200W and H191D binding to SOCS1.
Mutations in the von Hippel-Lindau (VHL) gene are responsible for VHL disease, congenital polycythemia, and are found in many sporadic tumor types as well.
The somatic JAK2 valine-to-phenylalanine (V617F) mutation has been detected in up to 90% of patients with polycythemia and in a sizeable proportion of patients with other myeloproliferative disorders such as essential thrombocythemia and idiopathic myelofibrosis.
Erythropoietin hypersensitivity in primary familial and congenital polycythemia: role of tyrosines Y285 and Y344 in erythropoietin receptor cytoplasmic domain.