title: 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.
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.
  
  
  METHODS
  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.
authors.affiliation: Department of Laboratory Medicine, Jikei University, Daisan Hospital, Komae City, Tokyo, Japan. kayosudo@jikei.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Sudo
authors.forename: M
authors.initials: M
authors.lastname: Maekawa
authors.forename: N
authors.initials: N
authors.lastname: Houki
authors.forename: T
authors.initials: T
authors.lastname: Okuda
authors.forename: S
authors.initials: S
authors.lastname: Akizuki
authors.forename: T
authors.initials: T
authors.lastname: Magara
authors.forename: K
authors.initials: K
authors.lastname: Kawano
mesh_terms: D000328:Adult; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000172:deficiency* / Q000235:genetics*; D008297:Male; D017384:Sequence Deletion
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase