Description:
HEMOPHILIA B; HEMB
5,10-@METHYLENETETRAHYDROFOLATE REDUCTASE; MTHFR
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Repository
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NIGMS Human Genetic Cell Repository
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| Subcollection |
Chromosome Abnormalities |
| Class |
X Chromosome Markers |
| Quantity |
25 µg |
| Quantitation Method |
Please see our FAQ |
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Biopsy Source
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Peripheral vein
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Cell Type
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B-Lymphocyte
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Tissue Type
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Blood
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Transformant
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Epstein-Barr Virus
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Sample Source
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DNA from LCL
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Race
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White
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Relation to Proband
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proband
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Confirmation
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Clinical summary/Case history
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Species
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Homo sapiens
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Common Name
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Human
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Remarks
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| IDENTIFICATION OF SPECIES OF ORIGIN |
Species of Origin Confirmed by Nucleoside Phosphorylase, Glucose-6-Phosphate Dehydrogenase, and Lactate Dehydrogenase Isoenzyme Electrophoresis |
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| Gene |
MTHFR |
| Chromosomal Location |
1p36.3 |
| Allelic Variant 1 |
607093.0003; MTHFR THERMOLABILE POLYMORPHISM |
| Identified Mutation |
677C>T; Frosst et al. [Nature Genet. 10: 111-113 (1995)] identified a C-to-T substitution at nucleotide 677 that converted an alanine to a valine residue. The alteration created a HinfI site that was used to screen 114 unselected French-Canadian chromosomes; the allele frequency of the substitution was 0.38. The mutation in the heterozygous or homozygous state correlated with reduced enzyme activity and increased thermolability in lymphocyte extracts; in vitro expression of the mutagenized cDNA containing the mutation confirmed its effect on thermolability of MTHFR. Individuals homozygous for the mutation had significantly elevated plasma homocysteine levels. Thus, the 677C-T mutation may represent an important genetic risk factor in vascular disease. |
| Remarks |
Factor IX deficiency diagnosed at age 15 mos; Factor IX level <1%; hemarthroses involving multiple joints & a massive intramuscular hematoma; prolonged PPT; mother & 2 sisters have normal Factor IX levels; donor subject is heterozygous for a C>T mutation at nucleotide 677 in exon 4 of the methylenetetrahydrofolate reductase (MTHFR) gene [677C>T] that results in a substitution of a valine for an alanine at codon 222 [Ala222Val (A222V)]; donor subject is homozygous normal for the R506Q mutation in the F5 gene and for the 20210G>A variant in the prothrombin gene (F2) |
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