Fechtner syndrome

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Classification according to ICD-10
D69.1 Qualitative platelet defects
ICD-10 online (WHO version 2019)

The fechtner syndrome is a very rare autosomal - dominant inherited disease . It is caused by a mutation in the MYH9 gene. Fechtner syndrome, together with Sebastian syndrome , Epstein syndrome and May-Hegglin anomaly, belongs to the group of MYH9-associated diseases.

Cause and genetics

The autosomal dominant inheritance
From left to right: erythrocyte (red blood cell), platelet (activated) and leukocyte

Fechtner syndrome is caused by point mutations of the MYH9 gene , which is located in humans on chromosome 22 gene locus q11.2.

The gene codes for the heavy chain of a non-muscle myosin type IIA (NMMHC-IIA). This protein is in some blood cells, including monocytes and platelets , in the cochlea ( cochlear ) and in the kidneys expressed . The mutation disrupts the dimerization of the NMMHC-IIA protein. The result is instability and precipitation along with normal MYHIIA chains in the cytoplasm of the leukocytes . These precipitates form the cytoplasmic inclusions. The disruption of dimerization also causes a faulty organization of the cytoskeleton in the megakaryocytes , the precursor cells of platelets. This is the cause of macrothrombocytopenia , which is manifested by a lack of platelets (a so-called thrombocytopenia ) and oversized platelets with leukocyte inclusions. The size of the platelets can even exceed that of erythrocytes.

Epidemiology and prevalence

Due to the rarity of Fechtner syndrome, no reliable data are available on the epidemiology and prevalence . The prevalence, however, is well below 1: 500,000.

Symptoms and diagnosis

Symptoms of Fechtner's syndrome were also manifested in accordance with the sites of NMMHC-IIA gene expression . The patients affected by Fechtner syndrome show macrothrombocytopenia with leukocyte inclusion bodies. The inclusion bodies in the platelets are relatively small and usually difficult to see with routine staining . Immunofluorescence methods are more suitable for detection.

About half of the patients develop progressive hearing loss (49%).

In some patients, glomerulonephritis (inflammation of the kidney filters) and cataracts may develop . Both diseases do not necessarily arise, however, since the dimerization disorder of NMMHC-IIA can be compensated for by a different myosin form (type IIB).

In contrast to Sebastian Syndrome, most patients do not suffer from excessive bleeding.

therapy

The therapy is essentially symptomatic. A platelet transfusion may be necessary prior to surgery .

discovery

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

Individual evidence

  1. ↑ UCSC Genome Browser on Human Mar. 2006 Assembly: chr22: 35,007,273-35,113,958
  2. ↑ genome.ucsc.edu: Human Gene MYH9 (uc003apg.1) Description and Page Index
  3. ↑ A. Toren et al .: Genetic linkage of autosomal-dominant Alport syndrome with leukocyte inclusions and macrothrombocytopenia (Fechtner syndrome) to chromosome 22q11-13. In: Am. J. Hum. Genet. 65/1999, pp. 1711-1717. PMID 10577925
  4. ↑ a b c d C. Trichet: Fechtner Syndrome October 2006.
  5. ↑ W. Delb among others: The Fechtner syndrome: A rare differential diagnosis of Alport syndrome. In: ENT. 48/2000, pp. 616-620.
  6. ↑ LC Peterson et al.: Fechtner syndrome: a variant of Alport's syndrome with leukocyte inclusions and macrothrombocytopenia. In: Blood 65/1985, pp. 397-406. PMID 2981587 .
  7. ↑ R. Gershoni-Baruch include: Fechtner syndrome: clinical and genetic aspects. In: Am. J. Med. Genet. 31/1988, pp. 357-367. PMID 3232700 .

literature

Web links