Consanguinity and genetic diseases in North Africa and immigrants to Europe

Abstract

Endemic diseases are caused by environmental and genetic factors. While in this special issue several chapters deal with environmental factors, including infections, the present focus is on genetic causes of disease clustering due to inbreeding and recessive disease mechanisms. Consanguinity is implying sharing of genetic heritage because of marriage between close relatives originating from a common ancestor. With limited natural selection, recessive genes may become more frequent in an inbred compared with an outbred population. Consanguinity is common in North Africa (NA), and the estimates range from 40 to 49% of all marriages in Tunisia and 29-33% in Morocco. As a consequence, recessive disorders are common in the NA region, and we give some examples. Thalassaemia and sickle cell disease/anaemia constitute the most common inherited recessive disorders globally and they are common in NA, but with immigration they have spread to Europe and to other parts of the world. Another example is familial Mediterranean fever, which is common in the Eastern Mediterranean area. With immigrantion from that area to Sweden, it has become the most common hereditary autoinflammatory disease in that country, and there is no evidence that any native Swede would have been diagnosed with this disease. The examples discussed in this chapter show that the historic movement of populations and current immigration are influencing the concept of 'endemic' disease.

Prevalence of Metabolic Syndrome and its Related Risk Factors in the City of Oran, Algeria: the ISOR Study

“…But, it was lower than that found in the other countries of the Maghreb, Morocco (29%-39%) and Tunisia (40-49%). 47 However, no relationship was found with metabolic syndrome (data not shown).…”

Novel insights into FAS defects underlying autoimmune lymphoproliferative syndrome revealed by studies in consanguineous patients

“…The study of primary immune deficiencies (PIDs) in consanguineous populations is bringing novel insights into molecular basis and functioning of the different immune pathways involved in these diseases. Moreover, there is cumulative evidence that the deeply rooted tradition of parental consanguinity in patients originating from Middle East and North Africa region has resulted in an increased burden of autosomal recessive (AR) PIDs since consanguinity favors the expression of recessive alleles . Indeed, the AR mode of inheritance is shown to be the most common in these highly endogamous populations and accounts for a majority of PIDs entities diagnosed in these settings …”

Cancer of unknown primary is associated with diabetes

“…Although the estimated T2D patient population numbered 135 million in 1995, the current WHO estimates are over 300 million (Van Dieren et al, 2010). In many populations, the prevalence of T2D is more than 10%, with the highest rates in the Middle East (Anwar et al, 2014). With an increase in the prevalence of diabetes, concerns about diabetesassociated mortality are warranted.…”