Detection of hemizygosity in Hermansky - Pudlak syndrome by quantitative real-time PCR

A. E. Griffin, B. R. Cobb, P. D. Anderson, D. A. Claassen, A. Helip-Wooley, M. Huizing, William A. Gahl

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Hermansky - Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism, a bleeding diathesis and, in some patients, pulmonary fibrosis or granulomatous colitis. HPS is associated with biosynthesis defects of melanosomes, platelet-dense bodies, and lysosomes. There are seven genetic HPS subtypes; HPS-1 is the most common. We used a real-time quantitative PCR (qPCR) approach to investigate six HPS-1 patients, previously assigned as having homozygous mutations in the HPS1 gene. HPS1 gene copy numbers, calculated by use of a comparative Ct method, revealed that one patient was in fact hemizygous for her c.1189delC (S396delC) HPS1 mutation. The causative deletion/insertion was 13,966 bp in size, with defined breakpoints, and involved an adjacent gene (C10orf33). A mechanism of formation is proposed for the deletion/insertion, and both multiplex and qPCR indicated that the deletion/insertion was present in the patient, her brother, and her father. qPCR amplification is valuable for detecting deletions too small to be identified by fluorescence in situ hybridization. This demonstration of hemizygosity, performed using genomic DNA, can eliminate concerns about non-paternity and can verify the diagnosis of an autosomal recessive disorder when a DNA alteration appears to be homozygous by standard PCR and sequencing methods, and its pathogenicity is in doubt.

Original languageEnglish (US)
Pages (from-to)23-30
Number of pages8
JournalClinical Genetics
Issue number1
StatePublished - Jul 2005


  • Breakpoint
  • C10orf33
  • Genomic insertion/deletion
  • Hemizygosity
  • Hermansky-Pudlak syndrome
  • Real-time quantitative PCR

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


Dive into the research topics of 'Detection of hemizygosity in Hermansky - Pudlak syndrome by quantitative real-time PCR'. Together they form a unique fingerprint.

Cite this