Abstract :
[en] A one year old girl, born to consanguineous parents, presented with unexplained liver disease. Liver
biopsies revealed respiratory chain complex I and IV deficiencies. Progressive liver failure at 19
months led to liver transplantation. One year later, anemia and thrombocytopenia occurred due to
hypersplenism. Histopathological analyses of partial splenectomy showed the presence of Gaucher
cells, and Gaucher disease was confirmed by enzyme and genetic analyses. Respiratory chain
deficiency was considered as a possible artifact due to liver failure and cirrhosis. She was treated by
ERT. Clinical follow-up showed developmental delay, strabism, nystagmus and external
ophthalmoplegia. A mitochondrial disorder was considered again, and molecular analysis revealed a
mtDNA depletion syndrome due to homozygous MPV17 mutation. In the meantime, a young sister
presented with acute abdominal pain, pancytopenia and major hepatosplenomegaly. ERT for
Gaucher disease allowed visceral normalization, without any developmental delay or neurological
symptom. She was unaffected by the mtDNA depletion syndrome. Unfortunately, a third sister
systematically screened, was affected by both conditions. Despite ERT, she presents chronic
moderate liver dysfunction and mild hepatomegaly. Aged 3 years, she has marked developmental
delay and ophthalmoplegia. Metabolic investigations showed normal blood lactate, in basal
condition as well as following an oral glucose load
