Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutamic acid decarboxylase (GAD) catalyzes the conversion of glutamic acid to gamma-aminobutyric acid (GABA). Autoantibodies directed against GAD (antiGAD-Ab) have been described in patients with insulin-dependent diabetes mellitus, stiff-man syndrome, and in a few patients with progressive cerebellar ataxia. The presence of these autoantibodies suggests an autoimmune pathophysiological mechanism for the neurological manifestations in these disorders. However, the exact role of antiGAD-Ab and GABAergic neurotransmission in the pathogenesis of the neurological manifestations, particularly in progressive cerebellar ataxia, is not fully understood. The cases of two patients with subacute cerebellar ataxia associated with antiGAD-Ab presenting with abnormal eye movements are reported. One patient presented a periodic alternating nystagmus (PAN), whereas the other presented a downbeat nystagmus (DBN) and slow vertical saccades. The potential role of antiGAD-Ab and the resultant GABAergic neurotransmission deficit in oculomotor manifestations is discussed.
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PMID:Potential role of anti-GAD antibodies in abnormal eye movements. 1582 97

Glutamic acid decarboxylase (GAD) is the enzyme that catalyzes the conversion of glutamic acid to the neurotransmitter gamma-amino butyric acid. Antibodies against GAD (anti-GAD-Ab) are associated with an array of autoimmune-related neurological conditions, such as stiff-person syndrome, cerebellar ataxia, epilepsy and limbic encephalitis. The clinical spectrum of ataxia associated with anti-GAD-Ab comprises slowly progressive cerebellar ataxia syndrome evolving in months or years, associated with cerebellar atrophy on brain MRI. There are few reports of patients with ataxia associated with anti-GAD-Ab presenting with abnormal ocular movements, such as downbeat nystagmus (DBN).We present two patients with ataxia associated with anti-GAD-Ab from a large series of ataxic subjects who presented with cerebellar ataxia combined with spontaneous DBN. All patients underwent a thorough neurological evaluation with the use of ataxia scales, brain MRI scans, cerebrospinal fluid examination, 18FDG-PET/CT scans, laboratory work-up with on coneural and immune encephalitis antibodies, serum and cerebrospinal fluid levels of anti-GAD-Ab, and the antibody specificity index to measure the intrathecal synthesis of anti-GAD-Ab. All patients were treated with cycles of intravenous immunoglobulin and had mild/partial ataxia improvement and no improvement of DBN. The finding of DBN may work as a diagnostic clue in the context of adult-onset non-hereditary ataxias.
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PMID:Spontaneous downbeat nystagmus as a clue for the diagnosis of ataxia associated with anti-GAD antibodies. 2667 Oct 81

Diagnostic exome sequencing has recently emerged as an invaluable tool in determining the molecular etiology of cases involving dysmorphism and developmental delay that are otherwise unexplained by more traditional methods of genetic testing. Our patient was large for gestational age at 35 weeks, delivered to a 27-year-old primigravid Caucasian whose pregnancy was complicated by preeclampsia. Neonatal period was notable for hypoglycemia, apnea, bradycardia, hyperbilirubinemia, grade I intraventricular hemorrhage, subdural hematoma, laryngomalacia, hypotonia, and feeding difficulties. The patient had numerous minor dysmorphic features. At three and a half years of age, she has global developmental delays and nystagmus, and is being followed for a mediastinal neuroblastoma that is currently in remission. Karyotype and oligo-microarray were normal. Whole-exome, next generation sequencing (NGS) coupled to bioinformatic filtering and expert medical review at Ambry Genetics revealed 14 mutations in 9 genes, and these genes underwent medical review. A heterozygous de novo frameshift mutation, c.2737_2738dupGA p.D913Efs*59, in which two nucleotides are duplicated in exon 17 of the CLTC gene, results in substitution of glutamic acid for aspartic acid at position 913 of the protein, as well as a frame shift that results in a premature termination codon situated 58 amino acids downstream. Clathrin Heavy Chain 1 (CHC1) has been shown to play an important role in the brain for vesicle recycling and neurotransmitter release at pre-synaptic nerve terminals. There is also evidence implicating it in the proper development of the placenta during the early stages of pregnancy. The CLTC alteration identified herein is likely to provide an explanation for the patient's adverse phenotype. Ongoing functional studies will further define the impact of this alteration on CHC1 function and consequently, human disease.
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PMID:CLTC as a clinically novel gene associated with multiple malformations and developmental delay. 2682 84