Identification of an uncommon haptoglobin type using DNA and protein analysis

Hum Genet. 1993 Oct;92(4):364-6. doi: 10.1007/BF01247336.

Abstract

The inherited variations in haptoglobin phenotypes are attributed to the homozygous and heterozygous combinations of three common autosomal alleles: HP*1F, HP*1S and HP*2. HP*1F and HP*1S encode polypeptides that differ by two amino acids at positions 51 and 53. The formation of HP*2 is postulated to have resulted from a breakage and subsequent reunion event at non-homologous positions of two HP*1 alleles. The most common form of HP*2 is HP*2FS in which the 5' end of HP*2 resembles HP*1F and the 3' end resembles HP*1S. Homologous crossing over between HP*2 and either an HP*1F or HP*1S allele in HP*2/HP*1 heterozygotes can change the usual type of HP*2 to three other forms: HP*2SS, HP*2FF or HP*2SF. We describe a nuclear family in which the uncommon genotype HP*2SS is one parent caused initial confusion in assigning genotypes to the rest of the nuclear family. The data demonstrate the need for a cautious approach when deducing haptoglobin genotypes from molecular analysis alone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Blood Proteins / analysis*
  • Blotting, Southern
  • Corneal Dystrophies, Hereditary / genetics
  • DNA / analysis*
  • Electrophoresis, Starch Gel
  • Female
  • Genotype
  • Haptoglobins / genetics*
  • Humans
  • Male
  • Nucleic Acid Hybridization
  • Phenotype

Substances

  • Blood Proteins
  • Haptoglobins
  • DNA