[See: Morocco > Tamary et al., 2000].

[See: Morocco > Tamary et al., 2000].

Tamary et al. (2000) investigated the molecular basis of Fanconi anemia (FA) in 13 unrelated non-Ashkenazi Jewish FA patients (including one compound heterozygote of Ashkenazi and non-Ashkenazi extraction). The ethnic origin of the 13 patients, determined according to parents' country of birth, was as follows: seven Moroccan-Jewish, two Indian-Jewish, one Tunisian Jewish, one Iraqi-Jewish, and two of compound origins (Tunisian/Moroccan and Ashkenazi/Egyptian). Tamary et al. (2000) identified three novel mutations: 2172-2173insG (exon 24), the first 'Moroccan mutation'; 4275delT (exon 43), the second 'Moroccan mutation'; and 890-893del (exon 10), the 'Tunisian mutation'. The 2172-2173insG was found in 10 of the 13 Moroccan-Jewish FA alleles (77%) examined. The 4275delT mutation was found in two patients: at homozygous state in a Moroccan-Jewish patient and as compound heterozygote in the Tunisian/Moroccan patient (4275delT/2172-2173insG). The 890-893del mutation was identified in two unrelated families of Tunisian origin. The mutations in two Iraqi-Jewish alleles and one Egyptian-Jewish allele were not identified. Tamary et al. (2000) calculated the frequency of the 2172-2173insG Moroccan mutation to be 1:200. They also noted that this mutation is associated with a milder disease with a lower frequency of malformations, and development of bone marrow failure and leukemia at an older age. Also, the tetranucleotide CCTG repeat sequence, previously identified as a mutation hotspot in FANCA and other human genes, was found in the vicinity of 2172-2173insG and 890-893del. All carriers of each mutation within each ethnic group were found to have the same haplotype, suggesting for a common founder for each mutation.

Tamary et al. (2004) investigated the molecular basis of Fanconi anemia (FANCA and FANCG) in three consanguineous families with nine patients and an additional unrelated patient. In two consanguineous families with five affected individuals, Tamary et al. (2004) applied SSCP analysis coupled with RT-PCR and DNA sequencing for the exons of the FANCA gene and identified two unique disease-causing mutations: a gross deletion of exons 6-31 and splice-site mutation IVS 42-2A-C. Sequence analysis of the FANCA gross deletion revealed recombination between two highly homologous Alu elements. cDNA analysis suggested that the IVS 42-2A-C substitution abolishes the 3' splice-site and causes retention of intron 42 (173 bp) during pre-mRNA splicing. This change is predicted to cause retention of the 39 amino acids in the mature transcript, followed by a premature stop codon. The clinical condition of eight patients with FANCA mutations was severe and accompanied with a variety of malformations such as microcephaly, hypoplstic thumbs, Klippel-Feil disease, deafness, and others.

Bouchlaka et al. (2003) characterized the molecular defects underlying Fanconi Anemia in 39 Tunisian families that were genotyped with microsatellite markers linked to known FA gene. Of the 39 families, 34 belonged to the FAA group while one family was probably not linked to the FANCA gene. Haplotype analysis and homozygosity mapping showed that with the exception of one family, all patients were homozygous by descent for all markers overlapping the FANCA gene region. The screening for mutations of patients of the FAA group revealed four new mutations: two homozygous deletions 1693delT and 1751-1754del in exon 17 and exon 19 and two transitions 513G>A in exon 5 and IV-S24+166A>G. Bouchlaka et al. (2003) identified 11 polymorphisms, two of which are new: IVS24-5G/A and IVS24-6C/G. The mutations were detected in patients of consanguineous families with 60% first cousin degree and 25% second cousin degree.

[See also: Morocco > Tamary et al., 2000].