-
Description
- An X-linked recessive mental retardation syndrome.
- Characterized by:
- Dysmorphic features: relative macrocephaly, hypertelorism, downslanted palpebral fissures, prominent forehead with frontal hair upsweep, broad thumbs, and halluces.
- Hypotonia, constipation, partial agenesis of the corpus callosum.
- Some patients exhibit sensorineural hearing loss, joint laxity evolving into joint contractures.
- Hyperactivity and talkativeness are common.
-
History
- Initially described as 'FG syndrome' by Opitz and Kaveggia in 1974, using the initials of patients' surnames.
-
Genetic Heterogeneity
- Different forms of 'FG syndrome' identified:
- FGS2: Mutation in the FLNA gene (Xq28).
- FGS4: Mutation in the CASK gene (Xp11).
- FGS3: Mapped to Xp22.3.
- FGS5: Mapped to Xq22.3.
- MED12 gene mutation should be reserved for Opitz-Kaveggia syndrome.
- Different forms of 'FG syndrome' identified:
-
Clinical Features
- Initial descriptions included mental retardation, large head, imperforate anus, congenital hypotonia, and partial agenesis of the corpus callosum.
- Additional features include short stature, joint contractures, seizures, gastrointestinal defects, and congenital heart defects.
- Features such as broad great toes and frontal upsweep of hair have been observed in unrelated families.
- Associated features: sensorineural deafness, severe constipation, telecanthus, hypertelorism, macrocephaly, characteristic facial appearance, and personality traits.
- Behavioral characteristics include socially oriented and attention-seeking behaviors similar to Williams syndrome.
-
Diagnosis
- Defined as an X-linked multiple congenital anomaly-cognitive impairment disorder caused by the R961W mutation in the MED12 gene.
- Clinical criteria include small ears, characteristic facial features, congenital anomalies, and a distinctive personality.
-
Mapping
- Linkage analysis identified linkage to DXS441 at Xq13, confirming genetic heterogeneity.
- Inversion inv(X)(q12q28) associated with FG syndrome in some families.
-
Molecular Genetics
- MED12 gene, located at Xq13, influences thyroid function and is implicated in X-linked mental retardation.
Reference
Online Mendelian Inheritance in Man (OMIM). (2024). OPITZ-KAVEGGIA SYNDROME. Retrieved June 28, 2024, from https://www.omim.org/entry/305450
Cite this: ICNApedia contributors.Opitz-Kaveggia Syndrome (OKS). ICNApedia, The Child Neurology Knowledge Environment. 09 November 2024. Available at: https://icnapedia.org/knowledgebase/articles/opitz-kaveggia-syndrome-oks Accessed 09 November 2024.