Manx — questions to ask before paying a deposit
A responsible breeder will have these readily available. Deflection is a red flag.
Progressive retinal atrophy (PRA rdAc, CEP290)can shorten life or cause chronic painCommon in this breed
An inherited, late-onset loss of the retina's light-sensing cells that leads to blindness. It was first found in Abyssinians and is common in Siamese-group breeds. It is recessive, so a kitten is affected only if it inherits a copy from each parent. In the Manx the evidence is a small screen: 3 of 30 Manx in a 2022 screen of over 11,000 cats carried one copy, roughly one in ten, all three from Finland, while a 2010 survey found none among 19 Manx. Whether it runs through the breed or in particular lines is not known.
Ask to see: UC Davis VGL PRA rdAc (CEP290) DNA test result, on both parents
Anderson et al. 2022, PLOS Genetics (Table 2, S3 and S4 Tables, Manx row) (https://doi.org/10.1371/journal.pgen.1009804) · Menotti-Raymond et al. 2010, The Veterinary Journal (Table 1, Manx row) (https://doi.org/10.1016/j.tvjl.2009.08.010) · OMIA — Retinal degeneration II (cat) (https://omia.org/OMIA001244/9685/)
Sacrocaudal dysgenesis ("Manx syndrome")can shorten life or cause chronic pain
The same dominant gene that shortens or removes the tail can also disrupt development of the lowest spinal segments and the nerves supplying the hind legs, bladder and bowel. Effects range from none at all to hind-limb weakness, a hopping gait and incontinence, and can include spina bifida. Fully tailless cats ("rumpies") carry the highest risk; the more tail present, the lower the risk.
Ask to see: There is no DNA test for the Manx tail-length gene or for Manx syndrome. Ask for a veterinary neurological and orthopaedic exam of both parents (hind-limb function, tail-stump/sacral palpation, continence) and, for any cat showing signs, spinal imaging.
Vetlexicon Felis — Sacrocaudal dysgenesis of Manx cats (https://www.vetlexicon.com/felis/neurology/articles/sacrocaudal-dysgenesis-of-manx-cats/) · Veterinary Partner (VIN) — Manx Syndrome in Cats (https://veterinarypartner.vin.com/default.aspx?pid=19239&catId=102903&id=10662679)
Factor XII deficiency (F12)
Not a bleeding disorder. Cats short of clotting factor XII clot normally and are not known to bleed more than other cats, but the standard clotting screen run before surgery (the aPTT) comes back markedly prolonged, which can be mistaken for a dangerous bleeding disorder and lead to a postponed operation or unnecessary treatment. It is recessive, and two F12 variants are tested (c.1321delC and c.1631G>C); the clotting test is most prolonged in cats with two copies of both. In a 2022 screen of over 11,000 cats, 2 of 29 Manx carried one copy of c.1321delC (both from Finland), and none of the 4 Manx tested for c.1631G>C did: too few cats to say how common it is. The study's authors list the Manx among the breeds in which the deficiency has been documented in practice.
Ask to see: Factor XII deficiency (F12) DNA test result, on both parents. It does not affect the kitten's health, but its own result is worth giving to the vet before any surgery or clotting test.
Anderson et al. 2022, PLOS Genetics (Table 2, S3 and S4 Tables, Manx row) (https://doi.org/10.1371/journal.pgen.1009804) · Maruyama et al. 2019, Gene (https://doi.org/10.1016/j.gene.2019.04.053) · Bender et al. 2015, Veterinary Pathology (https://doi.org/10.1177/0300985814532821) · OMIA — Factor XII deficiency (cat) (https://omia.org/OMIA000364/9685/)