Apparent segregation of null alleles ascribed to deletions of the ornithine transcarbamylase gene in congenital hyperammonaemia

Prenat Diagn. 1995 Aug;15(8):757-61. doi: 10.1002/pd.1970150812.


Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle mapped to chromosome Xp21.1. Here, we show that apparent segregation of null alleles at the OTC locus and flanking polymorphic loci mimicked false maternity or false paternity in three affected families. Based on these observations, we suggest giving consideration to gene deletion when dealing with segregation of null alleles in OTC deficiency.

Publication types

  • Case Reports

MeSH terms

  • Alleles*
  • Ammonia / blood*
  • Female
  • Gene Deletion*
  • Humans
  • Infant, Newborn
  • Male
  • Ornithine Carbamoyltransferase / genetics*
  • Ornithine Carbamoyltransferase Deficiency Disease*
  • Pedigree
  • X Chromosome


  • Ammonia
  • Ornithine Carbamoyltransferase