ALLELE FREQUENCIES OF 4qA AND 4qB HAPLOTYPES AT THE 4q35 CHOROMOSOME REGION IN THE ARGENTINE POPULATION

BIDINOST CARLA; PAGNONI SABRINA; ROSA ALBERTO LUIS; QUINTERO, JULIETA

Congreso; CONGRESO CONJUNTO SAIB-SAMIGE 2020; 2020

SOCIEDAD ARGENTINA DE INVESTIGACION BIOQUIMICA Y BIOLOGIA MOLECULAR (SAIB)

A polymorphic tandem repeat of 3.3 Kb (D4Z4), consisting on 8-100 units, is present at the subtelomeric region of human chromosome 4q. Contractions of this tandem are associated with facioscapulohumeral muscular dystrophy (FSHD), an inherited progressive autosomal dominant neuromuscular disease. A D4Z4-linked polymorphic sequence named pLAM, distal to the tadem D4Z4, shows alternative haplotypes being the most relevant 4qA and 4qB. In previous reports we have used a molecular strategy, based on pulsed field gel electrophoresis (PFGE) followed by Southern blot hybridization and a chemiluminescence detection method, to characterize the 4qA and 4qB haplotypes and chromosome structure of complex 4q35-linked D4Z4 alleles. The study was performed using alternative specific probes (i.e., p13E11, 4qA and 4qB) from the 4q35 region as well as single and double digestions with alternative restriction enzymes (i.e., EcoRI, AvrII and HindIII) for D4Z4 tandems smaller than ̴ 50 Kb. The D4Z4 allele-sizes as well as their associated pLAM- 4qA and 4qB haplotypes was studied in a total of 156 anonymous DNA samples, corresponding to individuals from Latin-America having clinical diagnosis of FSHD. Our study allowed to establish the frequency of 4qA and 4qB alleles in the Argentine population