Observational Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 28, 2017; 23(36): 6715-6725
Published online Sep 28, 2017. doi: 10.3748/wjg.v23.i36.6715
Wilson’s disease in Lebanon and regional countries: Homozygosity and hepatic phenotype predominance
Kassem Barada, Aline El Haddad, Meghri Katerji, Mustapha Jomaa, Julnar Usta
Kassem Barada, Aline El Haddad, Department of Internal Medicine, American University of Beirut Medical Center, Beirut 110236, Lebanon
Meghri Katerji, Mustapha Jomaa, Julnar Usta, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut 110236, Lebanon
Author contributions: El Haddad A, Katerji M, Jomaa M compiled the data and helped in the literature review; Barada K and Usta J coordinated and supervised the research and the write up of the manuscript.
Supported by the Medical Practice Plan and University Research Board grants to J Usta at the American University of Beirut.
Institutional review board statement: The study was reviewed and approved by the American University of Beirut (AUB) Institutional Review Board (IRB Protocol No. BioCh.JU.01). Blood samples were drawn after seeking approval from each participant and obtaining their signature on the consent form.
Conflict-of-interest statement: The authors state they have no conflicts to declare.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Julnar Usta, PhD, Professor, Department of Biochemistry and Molecular Genetics, American University of Beirut, Riad el Solh, Beirut 110236, Lebanon. justa@aub.edu.lb
Telephone: +961-1-350000
Received: May 4, 2017
Peer-review started: May 5, 2017
First decision: June 7, 2017
Revised: June 16, 2017
Accepted: July 12, 2017
Article in press: July 12, 2017
Published online: September 28, 2017
Abstract
AIM

To determine the phenotypes and predominant disease-causing mutations in Lebanese patients with Wilson’s disease, as compared to regional non-European data.

METHODS

The clinical profile of 36 patients diagnosed in Lebanon was studied and their mutations were determined by molecular testing. All patients underwent full physical exam, including ophthalmologic slit-lamp examination ultrasound imaging of the liver, as well as measurement of serum ceruloplasmin and 24-h urinary-Cu levels. In addition, genetic screening using PCR followed by sequencing to determine disease-causing mutations and polymorphisms in the ATP7B gene was carried on extracted DNA from patients and immediate family members. Our phenotypic-genotypic findings were then compared to reported mutations in Wilson’s disease patients from regional Arab and non-European countries.

RESULTS

Patients belonged to extended consanguineous families. The majority were homozygous for the disease-causing mutation, with no predominant mutation identified. The most common mutation, detected in 4 out of 13 families, involved the ATP hinge region and was present in patients from Lebanon, Egypt, Iran and Turkey. Otherwise, mutations in Lebanese patients and those of the region were scattered over 17 exons of ATP7B. While the homozygous exon 12 mutation Trp939Cys was only detected in patients from Lebanon but none from the regional countries, the worldwide common mutation H1069Q was not present in the Lebanese and was rare in the region. Pure hepatic phenotype was predominant in patients from both Lebanon and the region (25%-65%). Furthermore, the majority of patients, including those who were asymptomatic, had evidence of some hepatic dysfunction. Pure neurologic phenotype was rare.

CONCLUSION

Findings do not support presence of a founder effect. Clinical and genetic screening is recommended for family members with index patients and unexplained hepatic dysfunction.

Keywords: Wilson Disease, Cu-metabolism, Phenotype, Genotype, ATP7B, Hepatic manifestations

Core tip: We report on the genotype-phenotype of 36 Lebanese patients with Wilson’s disease from 13 different families. The majority were homozygous for disease-causing mutations. The most common mutation worldwide, His1069Trp, was absent in our patients. The ATP hinge region may comprise a hot spot for mutations, as it was detected in 4 families. Hepatic phenotypes were predominant in both symptomatic and asymptomatic patients. Neurologic phenotypes were rare. Compared to findings reported in regional Arab and non-European countries, our results do not support a founder effect. Mutations are scattered over 17 exons, with no common or frequent mutation characterizing the region.