Disorders of sex development in cats with different complements of sex chromosomes

Abstract

The genetic background of disorders of sex development (DSDs) in cats is poorly understood, due to a relatively low number of such studies in this species. Here we present three new DSD cases with different complements of sex chromosomes. The first, an Oriental Shorthair cat with a rudimentary penis, abdominal atrophic testicles and lack of uterus appeared to be a freemartin, since leucocyte chimerism XX/XY and a lack of Y-linked genes (SRY and ZFY) were observed in DNA isolated from hair follicles. XXY trisomy was identified in the second case, a tortoiseshell Devon Rex male cat with atrophic scrotal testicles and a normal penis. Finally, a European Shorthair cat with atrophic testicles in a bifid scrotum, rudimentary penis and a lack of uterus had XY complement, including Y chromosome of normal size and morphology. Also presence of eight Y-linked genes, detected by PCR, was confirmed. Due to the low testosterone level in this last patient, we searched for a causative mutation in two candidate genes (HSD3B2 and HSD17B3) involved in the metabolism of this steroid hormone. Altogether, five polymorphic sites in HSD3B2 and two in HSD17B3 were found, but none of them showed associations with DSD phenotype. We thus excluded a possibility that the causative mutation is present in these genes. In conclusion, we confirmed that analysis of the sex chromosome complement is a crucial step in diagnosis of DSDs. However, extensive molecular studies of the genes involved in sex development are needed to elucidate the causes of DSDs in cats with normal complements of sex chromosomes.

Infertility in purebred cats – A review of the potential causes

“…Chromosomical or genetical problems are not uncommon in cats. Abnormal chromosomic formulas may be found, such as a monosomy 37X0, trisomies (39 XXY, 39XXX, 39XYY) chimerism or mosaicism [ 70 ]. This may lead to primary anoestrus or to infertility in females that seem to cycle normally, or to abortion of foetuses with an abnormal karyotype.…”

Fertile male tortoiseshell cat with true chimerism 38,XY/38,XY

“…A number of studies have attempted to study the genetic basis of tortoiseshell coats in male domestic cats. As the orange locus in the cat is X‐linked (Grahn et al., 2005), the most frequently expected cause of this phenotype is the presence of an extra X chromosome in the form of a trisomy XXY, mosaic variants XY/XXY or XY/XYY and also XX/XY chimerism (Balogh et al, 2015; Kosowska, Januszewski, Tokarska, Jach, & Zdrojewicz, 2001; Meyers‐Wallen, 2012; Szczerbal et al., 2018). Therefore, the expected side effect of such a coat is infertility associated with reproductive disorders.…”

“…Thus, the tortoiseshell coat in tomcats is most often associated with the occurrence of aberrations such as 39,XXY trisomy (Centerwall & Benirschke, 1975; Grahn et al., 2005; Kuiper, Hewicker‐Trautwein, & Distl, 2003; Pedersen et al., 2014; Szczerbal et al., 2018; Szczerbal, Stachowiak, Dzimira, Sliwa, & Switonski, 2015), chimerism: 38,XX/39,XXY (Pedersen et al., 2014), 38,XX/38,XY (Kuiper et al, 2003; Szczerbal et al., 2015) or the presence of the SRY gene in female: 38,XX ( SRY ‐positive) (Szczerbal et al., 2015) and also recently described case of testicular XX DSD in a tortoiseshell cat with male‐like external genitalia, and normal scrotum and testes (De Lorenzi et al., 2017). The occurrence of tortoiseshell colour in males has consequences such as infertility, smaller body size, strong urine odour, smaller testicular volume compared to healthy males and cryptorchidism (Pedersen et al., 2014).…”

Infertility In Queens: Clinical approach, experiences and challenges

“…Abnormal chromosomal patterns Abnormal chromosomal patterns are found quite commonly in cats, such as monosomy 37,Xo, trisomies (39,XXY, 39,XXX, 39,XYY), chimerism or mosaicism 55 (see the accompanying review on disorders of sexual development 56 ). This may lead to a lack of puberty or to infertility in females that seem to cycle normally, or to the abortion of fetuses with an abnormal karyotype.…”