Oh this is interesting for any dog, not just the Yorkie:
Dog Diseases | Broad Institute of MIT and Harvard
We need DNA samples from purebred dogs suffering from the diseases we are currently studying (described below), as well as from older, healthy dogs from the same breeds. If you would like to submit a sample, please ask your veterinarian to collect 5 milliliters of blood from your dog (click here for more information). Although we appreciate that many people and dogs want to help, using samples from only purebred dogs will ensure the fastest progress for all dogs.
Diseases we study:
Cancers
•Hemangiosarcoma
• Osteosarcoma (bone cancer)
• Lymphoma
• Mast Cell Tumors (MCT)
• Mammary Tumors
• Melanoma (skin cancer)
• Glioma
Cardiovascular Diseases
•Dilated Cardiomyopathy (DCM)
• Degenerative valve disease
Neurological Disease & Behavior
•Degenerative Myelopathy (DM)
• Idiopatic epilepsy
•Obsessive-compulsive disorder (OCD)
Immunological & Metabolic Diseases
•Familial Shar-Pei Fever (FSF)
• Addison's disease
•Symmetrical Lupoid Onychodystrophy (SLO)
•Atopic dermatitis
•Diabetes
•Lymphocytic thyroiditis
•Exocrine Pancreatic Insufficiency (EPI)
•Toller Diseases (SLE & SRMA)
Other
•Dermoid sinus (DS)
•Juvenile Demodicosis
•Juvenile Renal Dysplasia (JRD)
•Hairlessness/Canine Ectodermal Dysplaysia (CED)
•Progressive Cone-Rod Dystrophy (PCRD)
•Progressive Retinal Atrophy (PRA)
• Pseudopelade
•White coat color
•Pyometra