MYH9

MYH9 ( myosin, heavy chain 9) is a gene located on chromosome 22 in humans locus q11.2.

With MYH9 related syndromes and anomalies

Point mutations in MYH9 are responsible for four very rare autosomal dominant inherited diseases:

• May-Hegglin anomaly
• Sebastian syndrome
• Fechtner syndrome
• Epstein syndrome

The May-Hegglin anomaly is from these very rare diseases, the most common form.

The four associated with point mutations in MYH9 syndromes differ in the location of the point mutation, which in turn leads to different symptoms:

A macrothrombocytopenia is characterized by a lack of platelets (called thrombocytopenia) and large platelets.

In particular, in people of black African descent single nucleotide polymorphisms are associated with an unfavorable prognosis MYH9 in nephrosclerosis and focal segmental glomerulosclerosis. Responsible for the increased risk is probably not MYH9 itself, but the directly adjacent gene APOL1. Variants of this gene give carriers the resistance to infection with Trypanosoma brucei rhodesiense and thus a selective advantage. The gene coding for the protein APOL1 apolipoprotein LI ( APOL1 ), which was found only in humans and gorillas. If trypanosomes APOL1 record by endocytosis, APOL1 forms in the membrane of lysosomes pores, leading to lysis of the parasite cells. The pathogenetic mechanism through which APOL1 in humans leads to kidney damage is not yet known.

Genetics and construction

The MHY9 gene encodes the heavy chain of non- muscle myosin IIA ( NMMHC - IIA). This protein is expressed in a number of blood cells, including monocytes and platelets, in the cochlea ( cochlea) and in the kidneys.

Containing the human gene MYH9, as well as the murine, 41 exons. The encoded from the MYH9 gene murine NMMHC IIA protein consists of 1960 amino acids and is 98% identical to the human.