Fechtner syndrome

The Fechtner syndrome is a very rare autosomal dominant genetic disease. It is caused by a mutation of the gene MYH9. The Fechtner syndrome is grouped with the Sebastian syndrome, Epstein syndrome and the May-Hegglin anomaly in a group of MYH9 -associated disorders.

Cause and Genetics

The cause of the syndrome are Fechtner point mutations of the MYH9 gene, located in humans on chromosome 22 q11.2 locus.

The gene encoding 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. The mutation causes a disturbance of the dimerization of the NMMHC IIA protein. The result is an instability and precipitation with normal MYHIIA chains in the cytoplasm of the leukocytes. These precipitates form the cytoplasmic inclusions. The disruption of dimerization also causes a defective organization of the cytoskeleton in megakaryocytes, the precursor cells of platelets. This is the cause of the macrothrombocytopenia, which is manifested by a lack of platelets (called thrombocytopenia) and large platelets with leukocyte inclusions. The size of the platelets can even exceed that of erythrocytes.

Epidemiology and prevalence

Due to the rarity of the syndrome Fechtner no reliable data on the epidemiology and prevalence are available. The prevalence is well below 1:100,000.

Symptoms and Diagnosis

According to the sites of gene expression of NMMHC - IIA also the symptoms of Fechtner syndrome manifested. To view the areas affected by Fechtner syndrome patients with a macrothrombocytopenia Leukozyteneinschlusskörpern. The inclusion bodies in the platelets are relatively small and with a routine staining usually hard to detect. Immunofluorescence methods are better suited for detection.

Approximately half of the patients developed a progressive hearing loss ( 49%).

Some patients may also adjust ( an inflammation of the Nierenfilterchen ), as well as a cataract glomerulonephritis. However, both diseases represent a not necessarily because the dimerization disruption of NMMHC - IIA by another Myosinform (type IIB) can be compensated.

Most patients suffer - in contrast to Sebastian 's syndrome - not from abnormal bleeding.

Therapy

Treatment is essentially symptomatic. Before operations may require a platelet transfusion necessary.

Discovery

The Fechtner syndrome was first in 1985 by LC Peterson et al. described.