Atypical presentation of Pearson syndrome in an infant with suspected myelodysplastic syndrome.

Background: Anemia exhibits complex causation mechanisms and genetic heterogeneity. Some cases result in poor outcomes with multisystemic dysfunction, including renal tubulopathy. Early diagnosis is crucial to improve management.

Case-diagnosis/treatment: A 21-month-old female patient was admitted with severe anemia. Persistent neutropenia and dysplastic signs suggested myelodysplastic syndrome, but targeted gene panel results were negative. After multiple transfusions, spontaneous hematologic recovery was observed. At 4 years old, she presented failure to thrive, renal Fanconi syndrome, and severe metabolic acidosis. Differential diagnosis included Pearson syndrome (PS), a life-threatening condition associated with mitochondrial DNA (mtDNA), featuring anemia and pancreatic insufficiency. Further analysis revealed a ~ 7.5 kb mtDNA deletion. Until the age of 5, supportive care has been provided, without pancreatic insufficiency.

Conclusions: This PS case highlights the importance of genetic testing, even in the absence of typical features. Understanding the nature of mitochondrial disorders enables treatment tailoring and counseling about the prognosis.