Demyda-Peyrás Sebastián, Laseca Nora, Anaya Gabriel, Kij-Mitka Barbara, Molina Antonio, Karlau Ayelén, Valera Mercedes
Departamento de Producción Animal, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata 1900, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET LA PLATA), La Plata 1900, Argentina.
Animals (Basel). 2023 Feb 3;13(3):539. doi: 10.3390/ani13030539.
Chromosomal abnormalities are largely associated with fertility impairments in the domestic horse. To date, over 600 cases of individuals carrying abnormal chromosome complements have been reported, making the domestic horse the species with the highest prevalence. However, studies analyzing the prevalence of chromosomal diseases in whole populations are scarce. We, therefore, employed a two-step molecular tool to screen and diagnose chromosomal abnormalities in a large population of 25,237 Pura Raza Español horses. Individuals were first screened using short tandem repeats parentage testing results and phenotypic evaluations. Those animals showing results suggesting chromosomal abnormalities were re-tested using a single nucleotide polymorphism (SNP)-based diagnostic methodology to accurately determine the chromosomal complements. Thirteen individuals showed a positive screening, all of which were diagnosed as chromosomally abnormal, including five 64,XY mares with sex development disorders (DSD) and four cases of blood chimerism (two male/female and two female/female cases). In addition, we detected one Turner and one Klinefelter syndrome and two individuals carrying complex karyotypes. The overall prevalence in the entire population was ~0.05%, with the prevalence of 64,XY DSD and blood chimerism ~0.02% and ~0.016%, respectively. However, the overall results should be taken with caution since the individuals carrying Turner syndrome (in full (63,X) or mosaic (mos 63,X/64,XX) forms) cannot be detected due to limitations in the methodology employed. Finally, the lack of agreement between populational studies performed using karyotyping or molecular methods is discussed. To our knowledge, this is the largest populational study performed evaluating the prevalence of the most common chromosomal abnormalities in the domestic horse.
染色体异常在家马中很大程度上与生育障碍相关。迄今为止，已报道了600多例携带异常染色体组成的个体，使家马成为患病率最高的物种。然而，分析整个人口中染色体疾病患病率的研究很少。因此，我们采用了一种两步分子工具，对25237匹西班牙纯种马的大量群体进行染色体异常的筛查和诊断。首先使用短串联重复序列亲子鉴定结果和表型评估对个体进行筛查。那些结果显示可能存在染色体异常的动物，再使用基于单核苷酸多态性（SNP）的诊断方法进行重新检测，以准确确定染色体组成。13只个体筛查呈阳性，所有这些个体均被诊断为染色体异常，其中包括5匹患有性发育障碍（DSD）的64,XY母马和4例血液嵌合体（2例雄性/雌性和2例雌性/雌性）。此外，我们检测到1例特纳综合征和1例克兰费尔特综合征，以及2例携带复杂核型的个体。整个人群中的总体患病率约为0.05%，64,XY DSD和血液嵌合体的患病率分别约为0.02%和0.约016%。然而，由于所用方法的局限性，携带特纳综合征（完全型（63,X）或嵌合型（mos 63,X/64,XX））的个体无法检测到，因此总体结果应谨慎看待。最后，讨论了使用核型分析或分子方法进行的群体研究之间缺乏一致性的问题。据我们所知，这是评估家马中最常见染色体异常患病率的最大规模群体研究。
