Personalized genetic counseling for Stargardt disease: Offspring risk estimates based on variant severity

Stéphanie S Cornelis; Esmee H Runhart; Miriam Bauwens; Zelia Corradi; Elfride De Baere; Susanne Roosing; Lonneke Haer-Wigman; Claire-Marie Dhaenens; Anneke T Vulto-van Silfhout; Frans P M Cremers

doi:10.1016/j.ajhg.2022.01.008

Personalized genetic counseling for Stargardt disease: Offspring risk estimates based on variant severity

Am J Hum Genet. 2022 Mar 3;109(3):498-507. doi: 10.1016/j.ajhg.2022.01.008. Epub 2022 Feb 3.

Affiliations

¹ Department of Human Genetics, Radboud University Medical Center, 6525 Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, the Netherlands.
² Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, the Netherlands; Department of Ophthalmology, Radboud University Medical Center, 6525 Nijmegen, the Netherlands.
³ Center for Medical Genetics Ghent and Department of Biomolecular Medicine, Ghent University and Ghent University Hospital, 9000 Ghent, Belgium.
⁴ Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience and Cognition, 59000 Lille, France.
⁵ Department of Human Genetics, Radboud University Medical Center, 6525 Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, the Netherlands. Electronic address: frans.cremers@radboudumc.nl.

Abstract

Recurrence risk calculations in autosomal recessive diseases are complicated when the effect of genetic variants and their population frequencies and penetrances are unknown. An example of this is Stargardt disease (STGD1), a frequent recessive retinal disease caused by bi-allelic pathogenic variants in ABCA4. In this cross-sectional study, 1,619 ABCA4 variants from 5,579 individuals with STGD1 were collected and categorized by (1) severity based on statistical comparisons of their frequencies in STGD1-affected individuals versus the general population, (2) their observed versus expected homozygous occurrence in STGD1-affected individuals, (3) their occurrence in combination with established mild alleles in STGD1-affected individuals, and (4) previous functional and clinical studies. We used the sum allele frequencies of these severity categories to estimate recurrence risks for offspring of STGD1-affected individuals and carriers of pathogenic ABCA4 variants. The risk for offspring of an STGD1-affected individual with the "severe|severe" genotype or a "severe|mild with complete penetrance" genotype to develop STGD1 at some moment in life was estimated at 2.8%-3.1% (1 in 36-32 individuals) and 1.6%-1.8% (1 in 62-57 individuals), respectively. The risk to develop STGD1 in childhood was estimated to be 2- to 4-fold lower: 0.68%-0.79% (1 in 148-126) and 0.34%-0.39% (1 in 296-252), respectively. In conclusion, we established personalized recurrence risk calculations for STGD1-affected individuals with different combinations of variants. We thus propose an expanded genotype-based personalized counseling to appreciate the variable recurrence risks for STGD1-affected individuals. This represents a conceptual breakthrough because risk calculations for STGD1 may be exemplary for many other inherited diseases.

Keywords: STGD1, recurrence risk, ABCA4, genotype-phenotype correlation, personalized genetic counseling, autosomal recessive disease.

Publication types

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

MeSH terms

ATP-Binding Cassette Transporters* / genetics
Cross-Sectional Studies
Genetic Counseling*
Humans
Mutation
Stargardt Disease / genetics

Substances

ABCA4 protein, human
ATP-Binding Cassette Transporters