title: Is "milk crust" a transient form of golden retriever ichthyosis?
abstract: BACKGROUND
  A recessive inherited form of lamellar ichthyosis is well recognized in golden retrievers. In this breed, young puppies demonstrate a self-limiting scaling disorder which is commonly recognized by breeders, who use the term "milk crust" to describe this syndrome.
  
  
  OBJECTIVE
  To determine whether "milk crust" is a new keratinization disorder or a self-limiting form of golden retriever ichthyosis.
  
  
  METHODS
  A total of 179 golden retriever dogs (21 dams and 158 puppies) were examined.
  
  
  METHODS
  Dermatological examination and assessment of the patatin-like phospholipase-1 (PNPLA1) genotype by PCR testing of buccal mucosal swabs. Skin biopsies from one affected puppy were evaluated for histopathological abnormalities.
  
  
  RESULTS
  Forty-five of 158 (28%) puppies exhibited scaling at 8 weeks of age; 113 of 158 (72%) were dermatologically normal. Of 144 analysed samples, 40 of 144 (28%) puppies demonstrated a homozygous mutation of the PNPLA1 genotype [of which, 36 of 40 (90%) had signs of scaling], 77 of 144 (53%) demonstrated a heterozygous mutation and 27 of 144 (19%) were a normal wild-type. In six of 17 (35%) dams, a homozygous mutation of the PNPLA1 genotype was found, eight of 17 (47%) demonstrated a heterozygous mutation and three of 17 (18%) were normal wild-type. Dams with a homozygous mutation were clinically unaffected. A 1 year follow-up revealed that 23 of 28 (82%) puppies affected with this syndrome failed to develop typical signs of ichthyosis. In five of 28 (18%) dogs there was persistence of mild scaling.
  
  
  CONCLUSIONS
  We hypothesize that the clinical syndrome termed "milk crust" could represent a transient form of golden retriever ichthyosis. Remission is not fully linked to PNPLA1 genotype, suggesting that unknown factors may contribute to the clinical disease.
authors.affiliation: Clinic for Small Animal Internal Medicine, Justus-Liebig-Universität, Frankfurter Straße 126, 35392, Giessen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Roethig
authors.affiliation: Animagi Aurinkolahti, Solvikinkatu 13, 00990, Helsinki, Finland.
authors.forename: Kirsti J M
authors.initials: KJ
authors.lastname: Schildt
authors.affiliation: Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Länggasstraße 122, PO Box 8466, 3001, Bern, Switzerland.
authors.forename: Monika M
authors.initials: MM
authors.lastname: Welle
authors.affiliation: Tierdermatologie Wildermuth, Borsigstraße 7, 65205, Wiesbaden, Germany.
authors.forename: Brett E
authors.initials: BE
authors.lastname: Wildermuth
authors.affiliation: Clinic for Small Animal Internal Medicine, Justus-Liebig-Universität, Frankfurter Straße 126, 35392, Giessen, Germany.
authors.forename: Reto
authors.initials: R
authors.lastname: Neiger
authors.affiliation: Clinic for Small Animal Internal Medicine, Justus-Liebig-Universität, Frankfurter Straße 126, 35392, Giessen, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Thom
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001706:Biopsy / Q000662:veterinary; D004283:Dog Diseases / Q000235:genetics / Q000473:pathology*; D004285:Dogs; D006579:Heterozygote; D006720:Homozygote; D007057:Ichthyosis / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D008049:Lipase / Q000235:genetics; D009154:Mutation; D012867:Skin / Q000473:pathology
chemical_list: D008049:Lipase