Yorkshire Terrier: inherited diseases and health

Updated 2026-09-30 · 3 sources

Based on: OMIA (University of Sydney), Science for Animal Welfare (UFAW), Wikidata

Breed health

The inherited conditions below have been documented in this breed in published research. That does not mean your dog has them or will get them – but it helps to know the names when you talk to a breeder or a vet.

Conditions this breed is prone to

Veterinary charities list this breed as more likely than others to get these conditions. Read the signs and what to do:

Yorkshire Terrier and chocolate: how much is dangerous?

Typical adult weight: 3.2 kg. Grams of chocolate at which signs can start (20 mg/kg) and at which severe signs are reported (40 mg/kg):

Dog weight	Milk	Dark 70–85%	Baking / unsweetened
3.2 kg	32 g signs 64 g severe	8.0 g signs 16 g severe	4.6 g signs 9.1 g severe

Based on published doses: signs from about 20 mg/kg, severe signs from 40 mg/kg (US FDA, Cortinovis & Caloni 2016, Swedish Poison Information Centre). An estimate, not a diagnosis.

Check the exact amount with the chocolate calculator →

Inherited conditions documented in the breed

Conditions documented: 25

A gene variant is known for 12 of the conditions below, so a DNA test may exist. Ask your vet or the breed club.

Condition	Body system	Inheritance	Gene variant known
Avascular Necrosis of the Femoral Head^[2]	–	–	–
Coat colour, dilution, MLPH-related^[1]	Pigmentation	Autosomal recessive	Yes
Dermoid sinus^[1]	Integument (skin)	–	Yes
Diabetes Mellitus^[2]	–	–	–
Distichiasis^[2]	–	–	–
Fanconi syndrome^[1]	Renal / urinary system	–	–
Hypohidrotic ectodermal dysplasia, X-linked, EDA-related^[1]	Integument (skin)	X-linked recessive	Yes
L-2-hydroxyglutaricacidemia^[1]	Nervous system	Autosomal recessive	Yes
Lens luxation^[1]	Vision / eye	Autosomal recessive	Yes
Ligneous membranitis^[1]	Vision / eye	Autosomal recessive	Yes
Meningoencephalitis^[1]	Nervous system	Multifactorial	No
Myelopathy, fibrocartilaginous embolic^[1]	Nervous system	–	–
Myxomatous valvular degeneration^[1]	Cardiovascular system	Multifactorial	No
Necrotising encephalopathy, subacute, of Leigh^[1]	Nervous system	Autosomal recessive	Yes
Patellar Luxation^[2]	–	–	–
Persistent Mullerian duct syndrome, generic^[1]	Reproductive system	–	–
Polycythemia^[1]	Haematopoietic system	Somatic mutation	Yes
Polydactyly^[1]	Skeleton (incl. short stature & teeth)	Autosomal dominant	Yes
Portosystemic Shunt^[2]	–	–	–
Progressive rod-cone degeneration, PRCD-related^[1]	Vision / eye	Autosomal recessive	Yes
Retinal dysplasia^[1]	Vision / eye	–	–
Tracheal Collapse^[2]	–	–	–
Von Willebrand disease I^[1]	Haematopoietic system	Autosomal	Yes
XY difference of sexual development, generic^[1]	Reproductive system	–	–
XY sex reversal, NR5A1-related^[1]	Reproductive system	–	Yes

What this list means

“Documented in the breed” means at least one published case or study – it says nothing about how common the condition is.
Many of these conditions are rare. A responsible breeder can tell you which health tests the parents have had.
Where the gene variant is known, a DNA test may exist – ask your vet or the breed club.
If your pet shows signs of illness, contact your vet. This page cannot tell you whether your pet is ill.

About the breed

Origin: England
Weight: 3.2 kg
FCI number: 086

^[3]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

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Sources

How this page was made: the list is taken directly from the sources below; nothing on it was written by AI. Names of conditions may be machine-translated. It is information, not a diagnosis. How we write our pages