Platelet findings in 22q11.2 deletion syndrome correlate with disease manifestations but do not correlate with GPIb surface expression

Ian M. Campbell, T. Blaine Crowley, Chintan Jobaliya, Alice Bailey, Daniel E. McGinn, Kimberly Gaiser, Anne Bassett, Raquel E. Gur, Bernice Morrow, Beverly S. Emanuel, Aime T. Franco, Deborah French, Elaine H. Zackai, Donna M. McDonald-McGinn, Michele P. Lambert

Research output: Contribution to journalArticlepeer-review

Abstract

Prior studies have demonstrated that patients with chromosome 22q11.2 deletion syndrome (22q11.2DS) have lower platelet counts (PC) compared to non-deleted populations. They also have an increased mean platelet volume. The mechanism for this has been postulated to be haploinsufficiency of the GPIBB gene. We examined platelet parameters, deletion size and factors known to influence counts, including status of thyroid hormone and congenital heart disease (CHD), in a population of 825 patients with 22q11.2DS. We also measured surface expression of GPIB-IX complex by flow cytometry. The major determinant of PC was deletion status of GP1BB, regardless of surface expression or other factors. Patients with nested distal chromosome 22q11.2 deletions (those with GP1BB present) had higher PCs than those with proximal deletions where GP1BB is deleted. Patients with 22q11.2DS also demonstrated an accelerated PC decrease with age, occurring in childhood. These data demonstrate that genes within the proximal deletion segment drive PC differences in 22q11.2DS and suggest that PC reference ranges may need to be adjusted for age and deletion size in 22q11.2DS populations. Bleeding did not correlate with either platelet count or GPIb expression. Further studies into drivers of expression of GPIb and associations with severe thrombocytopenia and immune thrombocytopenia are needed to inform clinical care.

Original languageEnglish (US)
Pages (from-to)109-113
Number of pages5
JournalClinical Genetics
Volume103
Issue number1
DOIs
StatePublished - Jan 2023

Keywords

  • genetic syndrome
  • genomic deletion
  • genotype–phenotype correlation
  • platelets

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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