Comorbidity in the Tunisian population

Abstract

Genetic diseases in the Tunisian population represent a real problem of public health as their spectrum encompasses more than 400 disorders. Their frequency and distribution in the country have been influenced by demographic, economic and social features especially consanguinity. In this article, we report on genetic disease association referred to as comorbidity and discuss factors influencing their expressivity. Seventy-five disease associations have been reported among Tunisian families. This comorbidity could be individual or familial. In 39 comorbid associations, consanguinity was noted. Twenty-one founder and 11 private mutations are the cause of 34 primary diseases and 13 of associated diseases. As the information dealing with this phenomenon is fragmented, we proposed to centralize it in this report in order to draw both clinicians' and researcher's attention on the occurrence of such disease associations in inbred populations as it makes genetic counseling and prenatal diagnosis challenging even when mutations are known.

Cytogenetic and molecular diagnosis of Fanconi anemia revealed two hidden phenotypes: Disorder of sex development and cerebro‐oculo‐facio‐skeletal syndrome

“…The co‐occurrence of more than one genetic disease affecting one individual and/or different members from the same family is known as comorbidity. This phenomenon seems to be frequently reported in highly inbred populations as described by Romdhaneet al (), where 75 disease associations were reported. While Libyan population is characterized by its heterogeneous ethnic background and high rate of consanguinity (Abudejaja et al, ), the report of multiple disease associations in the same individual could be expected.…”

“…While Libyan population is characterized by its heterogeneous ethnic background and high rate of consanguinity (Abudejaja et al, ), the report of multiple disease associations in the same individual could be expected. The main challenging consequence of comorbidity is undoubtedly the possibility of misdiagnosis especially when phenotypes are extremely rare and overlapping as one phenotype could be hidden by another (Romdhaneet al, ).…”

Genetics and genomic medicine in Tunisia

“…Autosomal dominant disorders represent 23% of all genetic disorders reported in the country, while 5.4% are X‐linked (Romdhane & Abdelhak, ). More than one genetic condition per family, referred to as comorbidity, was also recently reported (Romdhane et al., ).…”

A Tunisian family with a novel mutation in the gene CYP4F22 for lamellar ichthyosis and co‐occurrence of hearing loss in a child due to mutation in the SLC26A4 gene

“…These marriages are practically the norm in some regions, in particular in the Southern part of the country . It has been estimated that autosomal recessive diseases risk is increased six fold as a consequence of consanguineous marriage . In addition, the co‐occurrence of two or more diseases, although rare, might be encountered in endogamous populations and is challenging for appropriate diagnosis .…”

“…It has been estimated that autosomal recessive diseases risk is increased six fold as a consequence of consanguineous marriage . In addition, the co‐occurrence of two or more diseases, although rare, might be encountered in endogamous populations and is challenging for appropriate diagnosis . Autosomal recessive congenital ichthyosis (ARCI) includes a wide range of different clinical subtypes: congenital ichthyosis form erythroderma (CIE; Online Mendelian Inheritance in Man [OMIM] 242100); lamellar ichthyosis (LI; OMIM 242300); and harlequin ichthyosis (HI; OMIM 242500) .…”