FACIOSCAPULOHUMERAL MUSCULAR DYSTROPHY TYPE 1 (FSHD1) IN ARGENTINA: A MOLECULAR GENETICS-BASED EPIDEMIOLOGICAL STUDY

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

Congreso; 27th Annual FSH Society International Research Congress 2020; 2020

FSH Society

Facioscapulohumeral muscular dystrophy (FSHD) is one of the most prevalent neuromuscular disorders with a prevalence of 1:20000 to 1:8000 along with Steinert myotonic dystrophy (DM) after Duchenne muscular dystrophy (DMD). This form result from a contraction of the highly polymorphic D4Z4 macrosatellite repeat array on chromosome 4q35,where each D4Z4 unit is 3.3 kb in size. In the healthy population, this array contains 11?100 units. Deletion events that lead to 4q arrays of 1?10 D4Z4 units are associated with the onset of FSHD1. International spreading of FSHD1 in different worldwide populations has been reported. In this presentation we report the molecular characterization of 156 samples with clinical diagnosis of FSHD. From the total amount of patients, 55% presented a shortened array. Also, we found one patient that presented a normal allele with permissive haplotype associated with a mutation in SMCHD1 gene (c.3425G>C) confirming FSHD2 diagnosis. The characterization of 4qA/4qAB haplotype indicated that all the patients carrying a short D4Z4 allele also carried a 4qA haplotype in agreement with a previous publication. D4Z4-4q35 alleles present in this 156 samples distributed in groups of 1-4 D4Z4, 5-7 D4Z4, 8-10 D4Z4 and more than 11 D4Z4 repeats show a distribution of 21%, 14%, 20% and 45% respectively. This work represents the first characterization of a large number of FSHD individuals in latinoamerica.