GTR Home > Conditions/Phenotypes > FG syndrome 4


FG syndrome-4 is an X-linked recessive mental retardation syndrome characterized by congenital hypotonia, constipation, behavioral disturbances, and dysmorphic features (summary by Piluso et al., 2003). The name 'FG' derives from the first description of the disorder (FGS1; 305450) by Opitz and Kaveggia (1974), who named it 'FG syndrome' according to the Opitz system of using initials of patients' surnames. For a phenotypic description and a discussion of genetic heterogeneity of FG syndrome, see FGS1 (305450). FGS4 is typically associated with missense or hypomorphic mutations in the CASK gene. See also the more severe disorder MICPCH (300749), an allelic disorder caused by complete loss-of-function mutations in the CASK gene (Tarpey et al., 2009). [from OMIM]

Available tests

23 tests are in the database for this condition. Compare labs offering these tests.

Check Associated genes for additional relevant tests.

Associated genes

  • Also known as: RP11-540L11.1, CAGH39, CAMGUK, CMG, FGS4, LIN2, MICPCH, MRXSNA, TNRC8, CASK
    Summary: calcium/calmodulin-dependent serine protein kinase (MAGUK family)

Clinical features

  • Neonatal hypotonia
  • Prominent forehead
  • Intellectual disability
  • Seizure
  • Feeding difficulties in infancy
  • Hypertelorism
  • Sensorineural hearing impairment
  • Wide nasal bridge
  • Global developmental delay
  • Scoliosis
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