HLA Class II Allele and Haplotype Diversity in Libyans and Their Genetic Relationships with Other Populations.

Background: Libya witnessed the succession of many civilizations and ethnic groups throughout history, thereby questioning the origin of present-day Libyans. Indeed, they were considered Africans given the geographical position of the country, Arabs at the cultural level, and Berbers because of the notable presence of Berber tribes. Genetic anthropology studies investigating the origin of Libyans were rarely reported, and thus little was known about the population structure of current Libyans, particularly at autosomic markers level. Methods: We examined HLA class II (DRB1, DQB1) gene profiles of 101 unrelated Libyans, and compared them with Arab-speaking communities and with Sub-Saharan and Mediterranean populations using Neighbour-Joining dendrograms, genetic distances, correspondence, and haplotype analysis. Results: Of the 42 DRB1 alleles identified, DRB1*07:01 (14.36%), DRB1*03:01 (12.38%) were the most frequent, while DQB1*02:01 (24.17%), DQB1*02:02 (13.86%), and DQB1*03:01 (12.38%) were the most frequent of the 17 DQB1 alleles detected. DRB1*03:01-DQB1*02:01 (6.93%), DRB1*07:01-DQB1*02:02 (4.45%), and DRB1*04:03-DQB1*03:02 (3.46%) were the most frequent DRB1-DQB1 haplotypes. Conclusion: Libyans appear to be closely related to North Africans, Saudis, and Iberians, but distinct from Levantine Arabs, East Mediterraneans, and Sub-Saharan Africans. This indicates limited genetic contribution of Levantine Arabs and Sub-Saharans on the makeup of Libyan gene pool. Our study confirmed genetic heterogeneity among Arab populations, with three identified groups. The first comprises North Africans, Saudis, and Kuwaitis who were related to Iberians and West Mediterraneans, while the second consists of Levantine Arabs who were close to East Mediterraneans, and the third contained Sudanese and Comorians, with a close relatedness to Sub-Saharans.

Do we know all there is to know about Familial Adenomatous Polyposis?

Familial Adenomatous Polyposis (FAP) and Attenuated FAP (AFAP) are caused by a germline mutation in the Adenomatous polyposis coli (APC) gene. Recently, a new pathway characterized by a biallelic mutation in the MYH gene, with a recessive model of inheritance was discovered for this inherited syndrome. This report describes a Tunisian patient with an attenuated FAP phenotype, presenting seven colon polyps and an adenocarcinoma but no detectable germline mutations in the FAP target genes. A well known somatic mutation was found in the APC mutation cluster region (MCR). This case shows that further studies are needed to fully understand all the pathways of the FAP syndrome.