Clinical, Clinopathological, Pathological and Genetic findings in Six Franches-Montagnes Foals with Suspected Hypertrigliceridemia-Induced Pancreatitis

Pancreatitis is a rare and underreported condition in foals, and its underlying causes remain poorly understood. This session presents novel findings from a retrospective case series that offers new insight into a hereditary basis for this condition.
In this case series, six Franches-Montagnes foals with confirmed pancreatitis at necropsy were examined. All foals were fillies and closely inbred to a single stallion, with pedigree analyses supporting an autosomal recessive mode of inheritance. The foals presented at a median age of 5 days (range 4–93), displaying common clinical signs including apathy, reluctance to nurse, fever, abdominal distension, and diarrhea. One foal exhibited primarily neurological signs most likely consistent with hepatoencephalic syndrome.
All six cases revealed severe hypertriglyceridemia (mean 33.3 mmol/L ± 8.2; reference interval 0.16–0.73 mmol/L). Lipase activity was markedly elevated in 4 out of 6 foals. All the foals were euthanized due to their bad general condition and/or the lack of successful treatment. Necropsy findings confirmed severe necrotizing pancreatitis in each case.
Genetic analyses identified a candidate causative variant affecting the LMF1 gene, which encodes lipase maturation factor 1. It was a frameshift variant XM_023616679.1:c.369_373delinsTCT or XP_023472447.1:p.(Leu125Argfs*193). All six foals carried the mutant allele in a homozygous state.
A causal relationship between severe hypertriglyceridemia and the postmortem diagnosis of pancreatitis in the present cases has been found by identifying a candidate variant in the LMF1 gene. Pancreatitis should be considered in the differential diagnosis of sick foals with diarrhea, colic, and possibly neurologic signs, especially those with high triglyceride levels. Since a genetic predisposition is associated with hypertriglyceridemia and pancreatitis, genetic testing and strict avoidance of carrier x carrier matings should be implemented to prevent this fatal condition in the future.