Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Initially described as a rare MCA/MR syndrome occurring only in boys, due to a recessive mutation on the X chromosome [Opitz and Kaveggia, 1974], the FG syndrome (FGS) now emerges as a more common disorder also occurring in girls. Based on over 50 reported cases, FGS is associated with developmental delay (especially speech), hypotonia, postnatal onset relative macrocephaly, prominent forehead, frontal hair upsweep, telecanthus, or ocular hypertelorism, thin vermilion border of the upper lip, relatively short fingers with broad thumbs and halluces, persistent fetal fingertip pads, anal anomalies, and/or constipation. Major malformations are rare, and include pyloric stenosis, anal agenesis, cryptorchidism, hypospadias, and congenital heart defects. Abnormal EEGs and seizures have been reported in almost 70% of patients. Brain MRI shows corpus callosum abnormalities associated with dilatation of lateral ventricles and, less frequently, periventricular nodular heterotopias, mild cerebellar defects, and reduced periventricular white matter. Chiari 1 malformation seems to be frequent. The behavior phenotype appears to be characterized by ADHD, and relatively less developed language, fine motor and executive function skills; whereas visual-spatial abilities seem to be a relative strength. Five candidate loci are already known but no gene identified. We describe 25 patients referred to the Stella Maris Institute for evaluation of DD/MR, and diagnosed as FGS. They were between 2 and 15 1/2 years at the first observation. High resolution banding, FRAXA/FRAXE DNA analysis, and subtelomere FISH analysis were performed in all of them, and all had normal results. Thirteen patients were followed-up from 6 months to 9 years. Our report focuses on physical, neurological, developmental findings, and natural history of FGS. Experience with our series of patients suggests that the syndrome may be common, and should be routinely considered in the evaluation of children and adolescents with DD/MR.
 ...
PMID:The FG syndrome: report of a large Italian series. 1669

We report on a 7-year-old girl with severe mental retardation (MR), autism, micro-brachycephaly, generalized muscle hypotonia with distal hypotrophy of lower limbs, scoliosis and facial dysmorphisms. Array-CGH analysis identified a 1.1 Mb deletion of chromosome Xq22.1. Further analysis demonstrated that the deletion was inherited from her mother who showed mild MR, short stature, brachycephaly, epilepsy and a Borderline Personality Disorder. Microsatellite segregation analysis revealed that the rearrangement arose de novo in the mother on the paternal X chromosome. The deleted Xq22.1 region contains part of the NXF gene cluster which is involved in mRNA nuclear export and metabolism. Among them, the NXF5 gene has already been linked to mental retardation whereas NXF2 protein has been recently found to be partner of FMRP in regulating Nxf1 mRNA stability in neuronal cells. The dosage imbalance of NXF5 and NXF2 genes may explain the severe phenotype in our patient.
 ...
PMID:Familial 1.1 Mb deletion in chromosome Xq22.1 associated with mental retardation and behavioural disorders in female patients. 2009 87

We describe two brothers with moderate to severe mental retardation, short stature, an unusual skull shape, early anterior balding, unusual facial morphology, hypogonadotrophic hypogonadism, small genitalia, and small patellae. The older sib had generalized hypotonia without focal neurological abnormalities or myotonia. His brother had epileptic fits in infancy and tonic-clonic seizures from 5 years on, and died at 8 years of age during a seizure with possibly an intra-cerebral haemorrhage. Both brothers had a very similar face characterized by a high anterior hair line, small and upslanting palpebral fissures, deeply set eyes, a broad nasal tip, and everted lower lip. Additional studies in the older sib included a CGH array, and molecular testing of PQBP1 and FRAXA, all with normal results. Investigations of maternal lymphocytes showed completely skewed X-inactivation. The phenotype in the sibs resembles the phenotype reported in three unrelated patients reported by Scholte et al. in 1991 (MIM %181515) and Fryns et al. in 1993, and confirms this to be a clinically distinct entity. As all reported cases have been males, including two brothers, none of the parents were consanguineous, cytogenetic studies failed to show abnormalities, and X-inactivation was completely skewed in one of the mothers, we suggest this entity to follow an X-linked recessive pattern of inheritance.
 ...
PMID:Mental retardation, premature balding, small genitalia, small acra and small patellae in brothers: confirmation of an entity. 2062 1

CYFIP2, encoding the evolutionary highly conserved cytoplasmic FMRP interacting protein 2, has previously been proposed as a candidate gene for intellectual disability and autism because of its important role linking FMRP-dependent transcription regulation and actin polymerization via the WAVE regulatory complex (WRC). Recently, de novo variants affecting the amino acid p.Arg87 of CYFIP2 were reported in four individuals with epileptic encephalopathy. We here report 12 independent patients harboring a variety of de novo variants in CYFIP2 broadening the molecular and clinical spectrum of a novel CYFIP2-related neurodevelopmental disorder. Using trio whole-exome or -genome sequencing, we identified 12 independent patients carrying a total of eight distinct de novo variants in CYFIP2 with a shared phenotype of intellectual disability, seizures, and muscular hypotonia. We detected seven different missense variants, of which two occurred recurrently (p.(Arg87Cys) and p.(Ile664Met)), and a splice donor variant in the last intron for which we showed exon skipping in the transcript. The latter is expected to escape nonsense-mediated mRNA decay resulting in a truncated protein. Despite the large spacing in the primary structure, the variants spatially cluster in the tertiary structure and are all predicted to weaken the interaction with WAVE1 or NCKAP1 of the actin polymerization regulating WRC-complex. Preliminary genotype-phenotype correlation indicates a profound phenotype in p.Arg87 substitutions and a more variable phenotype in other alterations. This study evidenced a variety of de novo variants in CYFIP2 as a novel cause of mostly severe intellectual disability with seizures and muscular hypotonia.
 ...
PMID:Spatially clustering de novo variants in CYFIP2, encoding the cytoplasmic FMRP interacting protein 2, cause intellectual disability and seizures. 3066 14