Johnson Syndrome
| Classification according to ICD-10 | |
|---|---|
| Q87.8 | Other specified congenital malformation syndromes, not elsewhere classified |
| ICD-10 online (WHO version 2019) | |
The Johnson syndrome is a very rare congenital to the syndromic X-linked mental retardation scoring disease with the main features of mental retardation , macrocephaly and enlarged testicles ( Makroorchidie ).
Synonyms are: mental retardation, X-linked - macrocephaly - macroorchidy
The name refers to the first author of the first description from 1998 by the American human geneticist John P. Johnson and colleagues.
The syndrome is not to be confused with Stevens-Johnson syndrome , a skin disease.
Spread and cause
The frequency is given as less than 1 in 1,000,000, so far 12 affected people have been described in a family with 12 members over two generations. The inheritance is X-linked - recessive . The causative gene has been mapped to chromosomal region Xq12-q21.
Clinical manifestations
Clinical criteria are:
- Intellectual disability in both sexes
- Macrocephaly
- macroorchy in most male patients
Macroorchy and macrocephaly without a reduction in intelligence are also possible.
literature
- P. Long, MM May, VM James, S. Grannò, JP Johnson, P. Tarpey, RE Stevenson, K. Harvey, CE Schwartz, RJ Harvey: Missense Mutation R338W in ARHGEF9 in a Family with X-linked Intellectual Disability with Variable Macrocephaly and Macro-Orchidism. In: Frontiers in molecular neuroscience. Vol. 8, 2015, p. 83, doi: 10.3389 / fnmol.2015.00083 , PMID 26834553 , PMC 4719118 (free full text).
Individual evidence
- ↑ a b c Mental retardation, X-linked - macrocephaly - macroorchidy. In: Orphanet (Rare Disease Database).
- ^ JP Johnson, R. Nelson, CE Schwartz: A family with mental retardation, variable macrocephaly and macro-orchidism, and linkage to Xq12-q21. In: Journal of medical genetics. Vol. 35, No. 12, December 1998, pp. 1026-1030, PMID 9863601 , PMC 1051516 (free full text).
