Case Report: A Novel Mutation in the ABCA1 Gene, Resulting in a Compound Heterozygote with Tangier Disease

Alex Pizzini1#, Egon Demetz1#, Lukas Lunger2,3#, Christiane Heim1, Georg Schäfer4, Martina Witsch-Baumgartner4, Guenter Weiss1, Ivan Tancevski1* and Christoph Ebenbichler2*

1Department of Internal Medicine II, Medical University of Innsbruck, Austria 2Department of Internal Medicine I, Medical University of Innsbruck, Austria 3Department of Urology, Technical University of Munich, Germany 4Neuropathology and Molecular Pathology, Medical University Innsbruck, Austria 5Division of Human Genetics, Medical University Innsbruck, Austria #These authors contributed equally to this work

^*Correspondance to: Christoph Ebenbichler 

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Abstract:

Background: Tangier Disease (TD) is a rare autosomal recessive disorder characterized by significantly reduced levels of plasma HDL-C, typically leading to an accumulation of cholesterol esters in various tissues. The clinical phenotype and degree of TD is highly variable. Case Summary: Here in we present a case study of a 50-year old female Caucasian patient with features typical of TD, and her relatives. Genetic analyses were performed using next generation sequencing. Peripheral Blood Mononuclear Cells (PBMCs) of the index patient, her children and four healthy volunteers were isolated to analyze cholesterol efflux capacity. ABCA1 protein expression was visualized using immunoblot analysis. Genetic analysis of the index patient revealed a compound heterozygosity for a novel mutation (c.1776delC) as well as a known mutation (c.1824delG) affecting the ABCA1 gene, associated with TD. The offspring, both heterozygous for c.1824delG, displayed impaired cholesterol efflux without clinical features of TD. Conclusion: This case-study expands the knowledge on mutations causing TD and confirms an impaired cholesterol efflux even in heterozygous individuals, underlining the importance of extended screening of relatives who may not directly present with clinical features typical of TD.

Keywords:

ABCA1; Tangier disease; Cholesterol efflux; Reverse cholesterol transport; Novel mutation

Cite the Article:

Pizzini A, Demetz E, Lunger L, Heim C, Schäfer G, Witsch-Baumgartner M, et al. Case Report: A Novel Mutation in the ABCA1 Gene, Resulting in a Compound Heterozygote with Tangier Disease. Ann Clin Case Rep. 2022; 7: 2189..