Retrospective detection of ITGB7 gene mutation in a holstein calf with chronic diarrhea that was suspected of hereditary cholesterol deficiency.

A homozygous individual for ITGB7 gene mutation, an autosomal recessive congenital disorder in Holstein cattle, was retrospectively identified by genotyping of 195 stored blood from patients less than 12 months of age. Other 24 patients (12.3%) showed heterozygous. The homozygous individual was a 107-day-old female calf born on March 2017, who presented with chronic diarrhea and severe hypocholesterolemia suggesting hereditary cholesterol deficiency (CD), but genotyping analysis showed negative for CD. The patient showed watery diarrhea, dehydration, and extreme emaciation. Necropsy revealed no apparent cause of chronic diarrhea. Histopathological examination revealed mild mucosal inflammation from the jejunum to the colon. Seven years after the patient's death, the availability of ITGB7 gene mutation testing revealed the patient to be homozygous.