A novel in-frame deletion mutation in a case of lactate dehydrogenase (LD) H subunit deficiency showing an atypical LD isoenzyme pattern in serum and erythrocytes.
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Sudo K, Maekawa M, Houki N, Okuda T, Akizuki S, Magara T, Kawano K
A novel in-frame deletion mutation in a case of lactate dehydrogenase (LD) H subunit deficiency showing an atypical LD isoenzyme pattern in serum and erythrocytes.
Clin Biochem. 1999 Mar;32(2):137-41.
- PubMed ID
- 10211631 [ View in PubMed]
- Abstract
OBJECTIVE: We report a case showing an atypical lactate dehydrogenase (LD) isoenzyme pattern involving deficiency only of LD-1 and LD-2 in serum and erythrocytes. LD activity in serum from this patient was extremely low, similar to complete LD-H deficiency, and also that in erythrocytes was low. DESIGN: The DNA fragment containing exon 1 through 7 of the LD-H gene were amplified by PCR and directly sequenced. Total RNA was prepared from venous blood and the proportion of LD-H cDNA to total LD cDNA was semiquantified. RESULTS: Genetic analysis by DNA sequencing detected a three base deletion (AAT) at codon 220 of exon 5, which caused a deletion of one asparagine. The present case did not show reduced LD-H expression at the mRNA level in whole blood. Residue 220 is involved in turning beta-J to alpha1-G and is not buried in the interior of the protein. The novel homozygous in-frame deletion mutation at codon 220 may cause a three-dimensional change of the subunit-binding domain.