Diagnostic implications of excessive homozygosity detected by SNP-based microarrays: consanguinity, uniparental disomy, and recessive single-gene mutations

Clin Lab Med. 2011 Dec;31(4):595-613, ix. doi: 10.1016/j.cll.2011.08.003. Epub 2011 Oct 20.


Single nucleotide polymorphism–based microarrays used in diagnostic laboratories for the detection of copy number alterations also provide data allowing for surveillance of the genome for regions of homozygosity. The finding of one (or more) long contiguous stretch of homozygosity (LCSH) in a constitutional (nonneoplastic) diagnostic setting can lead to the diagnosis of uniparental disomy involving an imprinted chromosome or homozygous single gene mutations. The focus of this review is to describe the analytical detection of LCSH, clinical implications of excessive homozygosity, and considerations for follow-up diagnostic testing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Consanguinity*
  • Cytogenetic Analysis
  • Female
  • Genes, Recessive*
  • Homozygote*
  • Humans
  • Male
  • Mutation*
  • Oligonucleotide Array Sequence Analysis*
  • Polymorphism, Single Nucleotide*
  • Uniparental Disomy / genetics*