Pancytopenia and vacuolation of marrow precursors associated with necrotizing encephalopathy
Subacute necrotizing encephalopathy (SNE) or Leigh disease is an autosomal recessive disorder associated with various defects of oxidative phosphorylation. Two reports have described the concurrence of SNE with pancytopenia and vacuolation of bone marrow precursors, and have raised the possibility that this symptom complex may be part of a spectrum of diseases which includes Pearson's syndrome (vacuolation of bone marrow precursors, sideroblastic anaemia, exocrine pancreatic dysfunction). We describe a case of Pearson's syndrome in which haematological manifestations antedated progressive neurological deterioration by several years. Cytogenetic studies showed an inverted duplication of chromosome 9 (qh) [inv dup (9) (qh)]. We suggest that cytopenia associated with vacuolation of bone marrow precursors even without clinically apparent central nervous system pathology should prompt consideration of SNE, or related diseases. Conversely, a diagnosis of SNE should prompt evaluation of other organ system functions including bone marrow. Cytogenetic evaluation of other patients with SNE may determine whether the 9 (qh) findings are pathogenetic.