Frequency of the severe combined immunodeficiency disease gene among horses in Morocco

Abstract

Severe combined immunodeficiency disease (SCID) of horses is an autosomal, recessive hereditary disease occurring among Arabian or crossbred Arabian horses. The genetic defect responsible was previously identified as a 5-base pair deletion in the gene encoding the catalytic subunit of the DNA dependant protein kinase (DNA-PKcs). This study was carried out to determine the frequency of SCID and identify horses carrying the gene for SCID among Arabian and Arabian crossbred stallions and mares in Morocco using a DNA-based test. Twenty-one horses were SCID carriers: 14 (7%) Arabians, 6 (4%) Arab-Barbs and one (33%) Anglo-Arab. After analysing their genealogy, 3 imported stallions were identified that disseminated the mutant gene of DNA-PKcs in Morocco.

Investigation of the SCID mutant allele in Turkish Arabian horses reared in some private farms of the Eskişehir region in Turkey

“…Several previous genetic studies have investigated the five nucleotide deletion in the DNA-PKcs gene using primers that yield a PCR product of 521 bp [25], 259 bp [15], 235 bp [16], 179 bp [10], 174 bp [22], 169 bp [8,26], 163 bp [1,9,19,27], 162 bp [11], and 135 bp [13,17] in different Arabian horse populations.…”

“…To detect wild and mutant SCID alleles, the amplified PCR products were electrophoresed on 10% [10], 8% [13,15], and 6% Polyacrylamide gel [8,27], 4% agarose gel [17], or capillary electrophoresis [9,11,16,19]. In addition to electrophoresis, sequencing analysis could be performed to identify the genotypes of a population in terms of the presence/absence of SCID mutant alleles, as in these studies [1,25].…”

“…Among Arabian horse populations tested using molecular methods, the SCID mutant gene was detected in the USA [8], the UK [9], Brazil [10], Morocco [11], Egypt [1], and South Africa [12], but could not be detected in Ukraine [13], Syria [14], Iran [15], Romania [16], Slovenia [17], Poland [18], or Turkey [19]. There was only one study on SCID in Turkish Arabian horses.…”

Investigation of severe combined immunodeficiency (SCID) disease of Arabian horses raised at the state stud farms in Turkey

“…After development of reliable and useful DNAbased tests, contemporary incidence values of SCID carrier and clinically affected foals have been increasingly reported from different countries (3,11,14,21,20,22,26). For example, it is reported that 17 of 204 (8.3%) foals are found SCID affected in Australia (11).…”

“…These include polymerase chain reaction analysis (3,14,26), polymerase chain reaction followed by southern hybridization analysis (17) and fragment and sequence analysis based on capillary electrophoresis (20). In this study, PCR followed by high-resolution agarose gel electrophoresis was chosen because of its user-friendly application and economical advantage (26).…”