Differential impact of consanguineous marriages on autosomal recessive diseases in Tunisia. Issue 2 (16th July 2015)

• Record Type: Journal Article
• Authors: Ben Halim, Nizar; Hsouna, Sana; Lasram, Khaled; Rejeb, Insaf; Walha, Asma; Talmoudi, Faten; Messai, Habib; Sabrine Ben Brick, Ahlem; Ouragini, Houyem; Cherif, Wafa; Nagara, Majdi; Rhouma, Faten Ben; Chouchene, Ibtissem; Ouechtati, Farah; Bouyacoub, Yosra; Ben Rekaya, Mariem; Messaoud, Olfa; Ben Ammar, Slim; El Matri, Leila; Tebib, Neji; Ben Dridi, Marie F.; Mokni, Mourad; Amouri, Ahlem; Kefi, Rym; Abdelhak, Sonia
• Is Part Of: American journal of human biology. Volume 28:Issue 2(2016:Mar./Apr.)
• Page Start: 171
• Page End: 180
• Publication Date: 2015-07-16
• Subjects: Human biology -- Periodicals; Physical anthropology -- Periodicals; Biologie humaine -- Périodiques; Anthropologie physique -- Périodiques; 612
• DOI: 10.1002/ajhb.22764
• Languages: English
• ISSNs: 1042-0533

Abstract

Abstract : Objectives: Consanguinity is common in Tunisia. However, little information exists on its impact on recessive disorders. In this study, we evaluate the impact of consanguineous marriages on the occurrence of some specific autosomal recessive disorders and consider how other factors, such as population substructure and mutation frequency, may be of equal importance in disease prevalence. Methods: Consanguinity profiles were retrospectively studied among 425 Tunisian patients suffering from autosomal recessive xeroderma pigmentosum, dystrophic epidermolysis bullosa, nonsyndromic retinitis pigmentosa, Gaucher disease, Fanconi anemia, glycogenosis type I, and ichthyosis, and compared to those of a healthy control sample. Results: Consanguinity was observed in 341 cases (64.94%). Consanguinity rates per disease were 75.63, 63.64, 60.64, 61.29, 57.89, 73.33, and 51.28%, respectively. First‐cousin marriages were the most common form of consanguinity (48.94%) with the percentages of 55.46, 45.46, 47.87, 48.39, 45.61, 56.66, and 35.90%, respectively. A very high level of geographic endogamy was also observed (93.92%), with the values by disease ranging between 75.86 and 96.64%. We observed an overall excess risk associated to consanguinity of nearly sevenfold which was proportional to the number of affected siblings and the frequency of disease allele in the family. Consanguinity was significantly associated with the first five cited diseases (odds ratio = 24.41, 15.17, 7.5, 5.53, and 5.07, respectively). However, no meaningful effects were reported among the remaining diseases. Conclusions: This study reveals a variation in the excess risk linked to consanguinity according to the type of disorder, suggesting the potential of cryptic population substructure to contribute to disease incidence in populations with complex social structure like Tunisia. It also emphasizes the role of other health and demographic aspects such as mutation frequency and reproductive replacement in diseases etiology. Am. J. Hum. Biol. 28:171–180, 2016. © 2015 Wiley Periodicals, Inc.