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

A de novo 4.1-megabase microdeletion of chromosome 1p34.2p34.3 has been identified by array-based comparative genomic hybridization in a young male with severely delayed development, microcephaly, pronounced hypotonia, and facial dysmorphism. The deleted region encompasses 48 genes, among them the glucose transporter 1 (SLC2A1 or GLUT1) gene. The deletion of the GLUT1 gene was in line with the abnormal ratio of cerebrospinal fluid (CSF) glucose to blood glucose, indicative of GLUT1 deficiency syndrome (MIM #606777). GLUT1 deficiency syndrome is characterized by therapy-resistant infantile seizures, developmental delay, acquired microcephaly, spasticity, ataxia, and a low concentration of glucose in the CSF. It is known that a ketogenic diet can lead to better control of seizures. This case study shows that identifying a microdeletion as the cause of learning disability is not only important for genetic counselling but might also lead to therapeutic intervention.
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PMID:A novel microdeletion in 1(p34.2p34.3), involving the SLC2A1 (GLUT1) gene, and severe delayed development. 1748 14

GLUT1 deficiency syndrome (GLUT1DS) is understood as a monogenetic disease caused by heterozygous SLC2A1 gene mutations with autosomaldominant and sporadic transmission. We report on a six-year-old girl from an inbred Arab family with moderate global developmental delay, epilepsy, ataxia, hypotonia, and hypoglycorrhachia (CSF glucose 36 mg/dL; CSF lactate 1.09 mmol/L; CSF/blood glucose ratio 0.44). Molecular analysis of the SLC2A1 gene identified a novel homozygous c1402C>T (p. Arg468Trp) mutation in exon 10 in the index patient and her asymptomatic younger sister. The mutation was absent in 120 control alleles of healthy individuals as well as in 400 alleles of other GLUT1DS patients. Arg468 represents a highly conserved, functionally important amino acid residue in the GLUT1 carboxy-terminus essential for substrate recognition and transport. Both unaffected parents were heterozygous for the mutation. A younger brother and two family members were healthy and carried the GLUT1 wild type. A ketogenic diet effectively controlled seizures in the index patient. We conclude that GLUT1DS can be transmitted as an autosomal recessive disease and provide new insights into genetic counselling for this treatable disorder.
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PMID:Autosomal recessive inheritance of GLUT1 deficiency syndrome. 2022 55

Epilepsies associated with inborn errors of metabolism (IEM) represent a major challenge. Seizures rarely dominate the clinical presentation, which is more frequently associated with other neurological symptoms, such as hypotonia and/or cognitive disturbances. Although epilepsy in IEM can be classified in various ways according to pathogenesis, age of onset, or electroclinical presentation, the most pragmatic approach is determined by whether they are accessible to specific treatment or not. The main potentially treatable causes comprise vitamin B6 (pyridoxine deficiency), biotine, and GLUT1 deficiency (GLUT1DS) syndromes. Folinic acid-dependent seizures are allelic with pyridoxine dependency. Incompletely treatable IEMs include pyridoxal phosphate, serine, and creatine deficiencies. The main IEMs that present with epilepsy but offer no specific treatment are nonketotic hyperglycinemia, mitochondrial disorders, sulfite oxidase deficiency, ceroid-lipofuscinosis, Menkes disease, and peroxisomal disorders.
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PMID:Epilepsy in inborn errors of metabolism. 2362 1

Glucose transporter type 1 deficiency syndrome (GLUT1-DS) was first described by De Vivo in 1991, and the classic clinical manifestations include infantile epilepsy, developmental delay, and acquired microcephaly. A neurological complex disorder including elements of hypotonia, spasticity, ataxia, and dystonia can frequently be present. GLUT1-DS is an inborn error of metabolism caused by impaired glucose transport through blood-brain barrier in the majority of patients because of mutation of solute carrier family 2 (facilitated glucose transporter) member 1 gene (SLC2A1), encoding the transporter protein. We report a 6-year-old girl with GLUT1-DS, which is caused by a novel heterozygous variant c.109dupC of the SLC2A1 gene. The dominating clinical features were ataxia, epilepsy started at 4 years, acquired microcephaly, and mild intellectual disability. Treatment with ketogenic diet showed clinical improvement with the reduction of ataxia and seizure control in a 10-month follow-up period.
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PMID:Glucose Transporter Type 1 Deficiency Syndrome: Developmental Delay and Early-Onset Ataxia in a Novel Mutation of the SLC2A1 Gene. 3093 99