Genotype-phenotype correlation in pseudoxanthoma elasticum

Jonas W. Bartstra, Sara Risseeuw, Pim A. de Jong, Bram van Os, Lianne Kalsbeek, Chris Mol, Annette F. Baas, Shana Verschuere, Olivier Vanakker, Ralph J. Florijn, Jeroen Hendrikse, Willem Mali, Saskia Imhof, Jeannette Ossewaarde-van Norel, Redmer van Leeuwen, Wilko Spiering*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Background and aims: Pseudoxanthoma elasticum (PXE) is caused by variants in the ABCC6 gene. It results in calcification in the skin, peripheral arteries and the eyes, but has considerable phenotypic variability. We investigated the association between the ABCC6 genotype and calcification and clinical phenotypes in these different organs. Methods: ABCC6 sequencing was performed in 289 PXE patients. Genotypes were grouped as two truncating, mixed, or two non-truncating variants. Arterial calcification mass was quantified on whole body, low dose CT scans; and peripheral arterial disease was measured with the ankle brachial index after treadmill test. The presence of pseudoxanthoma in the skin was systematically scored. Ophthalmological phenotypes were the length of angioid streaks as a measure of Bruchs membrane calcification, the presence of choroidal neovascularizations, severity of macular atrophy and visual acuity. Regression models were built to test the age and sex adjusted genotype-phenotype association. Results: 158 patients (median age 51 years) had two truncating variants, 96 (median age 54 years) a mixed genotype, 18 (median age 47 years) had two non-truncating variants. The mixed genotype was associated with lower peripheral (β: 0.39, 95%CI:-0.62;-0.17) and total (β: 0.28, 95%CI:-0.47;-0.10) arterial calcification mass scores, and lower prevalence of choroidal neovascularizations (OR: 0.41 95%CI:0.20; 0.83) compared to two truncating variants. No association with pseudoxanthomas was found. Conclusions: PXE patients with a mixed genotype have less severe arterial and ophthalmological phenotypes than patients with two truncating variants in the ABCC6 gene. Research into environmental and genetic modifiers might provide further insights into the unexplained phenotypic variability.

Original languageEnglish
Pages (from-to)18-26
Number of pages9
JournalAtherosclerosis
Volume324
DOIs
Publication statusPublished - May 2021

Keywords

  • ABCC6
  • Arterial calcification
  • Choroidal neovascularization
  • Genotype-phenotype
  • Peripheral arterial disease
  • Pseudoxanthoma elasticum
  • Genetic Association Studies
  • Humans
  • Middle Aged
  • Peripheral Arterial Disease/diagnostic imaging
  • Genotype
  • Phenotype
  • Pseudoxanthoma Elasticum/diagnosis

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