I hope this helps some. You can go to the link below and click on the diseases and read more about it.
Congenital and Genetic Conditions found with greater than average frequency in the Yorkshire Terrier (point to name for description):
Cataract Cushings Disease Demodicosis Detached Retina Distichiasis Entropion Hydrocephalus (Water on the Brain) Hypoplasia of Dens (odontoid process) Keratitis Sicca Legg-Calve-Perthes disease Patellar Luxation Patent Ductus Arteriosus (PDA) Persistent Pupillary Membrane Portosystemic Shunt Progressive Retinal Atrophy Retinal Dysplasia Seborrhea von Willebrands Disease
http://www.qualitydogs.com/Yorkshire...formation.html