Disease relevance of FGS1

• FG syndrome is an X-linked recessive condition in which mental retardation is associated with congenital hypotonia, macrocephaly, characteristic face, and constipation [1].
• FG syndrome is an X-linked condition comprising mental retardation, congenital hypotonia, macrocephaly, distinctive facial changes, and constipation or anal malformations [2].
• X-linked syndrome of mental retardation, short stature, and hypertelorism: a new syndrome or a further example of the FG syndrome [3]?
• These anomalies tend to occur in several members of the same family, where some craniofacial abnormalities reported as characteristic of the FG syndrome have also been encountered [4].
• Esophageal dysmotility, in particular "nutcracker esophagus," should be suspected in infants with the FG syndrome and screaming attacks [5].

Psychiatry related information on FGS1

• Specifically, higher rates of agreeableness and extraversion were not confirmed, though these constructs do not correspond perfectly with the traits of affability and gregariousness described in earlier published case studies of FG syndrome [6].

High impact information on FGS1

• Opitz-Kaveggia syndrome (also known as FG syndrome) is an X-linked disorder characterized by mental retardation, relative macrocephaly, hypotonia and constipation [7].
• Two retarded male cousins with odd facies, hypotonia, and severe constipation: possible examples of the X linked FG syndrome [8].
• RESULTS: Of 12 boys with FG syndrome, 6 had hypoplasia of the corpus callosum, and 3 of these had TCS (all with constipation and urinary symptoms) [9].
• Midline defects in FG syndrome: does tethered spinal cord contribute to the phenotype [9]?
• OBJECTIVES: FG syndrome is an X-linked recessive mental retardation syndrome with ano-rectal anomalies, constipation, and occasional urinary incontinence [9].

Biological context of FGS1

• The first locus for FG syndrome (FGS1) was linked to chromosome region Xq12-q21.31, but other families have been excluded from this locus [10].
• Heterogeneity was supported by the study of one family with apparent FG syndrome co-segregating with an inversion of X chromosome [inv(X)(q11q28)] ([FGS2], OMIM 300321) [Briault et al., 1999: Am J Med Genet 86:112-114 and Briault et al., 2000: Am J Med Genet 95:178-181] [11].
• Genetic heterogeneity has been demonstrated in FG syndrome [12].
• Although the phenotype is not completely typical of the FG syndrome and the coincidence of the FMR1 mutation and segregation of the MCA/MR phenotype are highly unlikely, the FMR1 mutation may affect morphogenesis more extensively and differently than the Martin-Bell syndrome does to effect an FG syndromelike phenotype in certain families [13].
• An Xq22.3 duplication detected by comparative genomic hybridization microarray (Array-CGH) defines a new locus (FGS5) for FG syndrome [14].

Anatomical context of FGS1

• Because tethered spinal cord syndrome (TCS) has similar symptoms, we evaluated imaging for TCS in patients with FG syndrome [9].
• The alpha4 gene lies in the linkage interval for FG syndrome, characterized by skeletal muscle and brain defects that coincide closely to the expression pattern of alpha4 [15].
• Some of these patients with FGS require decompression surgery, but the decision to operate can be difficult because of their developmental delay, difficulties with language skills, general fatigue, possibility of upper motor neuron dysfunction, behavioral problems, or failure to thrive, which may mask the symptoms of a Chiari I malformation [16].
• Serial evaluations of a patient with FG syndrome, whose sole central nervous system anomaly was agenesis of the corpus callosum, showed a consistent pattern over time [17].

Other interactions of FGS1

• FG syndrome: linkage analysis in two families supporting a new gene localization at Xp22.3 [FGS3] [11].
• Genetic heterogeneity of FG syndrome: a fourth locus (FGS4) maps to Xp11.4-p11.3 in an Italian family [10].
• Overlap in the clinical features of FG and Opitz GBBB syndromes warrants investigation of Alpha 4 as a candidate for causing FG syndrome [18].
• Since FG and Opitz G/BBB syndromes share many manifestations we considered MID2 a candidate gene for FG syndrome [14].
• During linkage analysis in a family with FG syndrome, a rare condition mapped to Xq12-q22.1, we detected the presence of an unusually small AR allele segregating within the pedigree [19].

Analytical, diagnostic and therapeutic context of FGS1

• Differential diagnosis between a number of clinical entities was considered, however, because ACC and the distinctive facial features were reminiscent of FG syndrome, DNA was analyzed for markers linked to the FGS1 locus at Xq13-q21 [20].
• Problems in genetic counseling and prenatal diagnosis, the possible overlap with X-linked corpus callosum agenesis and FG syndrome, and the different forms of X-linked complicated spastic paraplegia are discussed [21].

References