The neurological evolution of Pearson syndrome: case report and literature review.

BACKGROUND: Pearson syndrome (PS) is an uncommon specific syndrome among mitochondrial diseases. It has unique clinical presentations. AIMS: The purpose of this article is to clarify the neurological evolution, neuroimage findings, molecular genetic analysis and outcomes in PS cases with neurologic manifestations.
METHODS: We described the clinical progress of a female patient who was diagnosed as PS with a novel 6.0 kbp mitochondrial DNA deletion. She had typical clinical features of PS in early infancy followed by multiple organs involvement after the age of 1 year. At age 3, Kearns-Sayre syndrome (KSS) and Leigh syndrome (LS) developed. We also reviewed PS cases reported in the literature and analyzed the neurological evolution.
RESULTS: Total 55 PS cases, including our index case, had been reported. Among them, 11 cases had detailed clinical descriptions in terms of hypotonia, developmental delay, ataxia or tremor. In whom, PS might evolve into KSS and/or LS: three cases evolving into KSS; one case on the transition of KSS; three cases evolve into LS; our index case has both presentations. The neuroimage findings of PS were quite different which might be from normal to specific abnormal findings over the cerebral white matter, cerebellum, basal ganglion and brainstem. Among those cases, the molecular analysis revealed large-scale mitochondrial deletion around 3.1-6.0kbp. The outcome of PS was opposite: either early death before age 4 or survived beyond age 7.
CONCLUSIONS: The neurological features of PS have potential evolution changes that are from normal, mild neurological deficits to special mitochondrial syndromes: KSS and LS. Closely monitoring neurological symptoms, arranging eye fundus examinations and neuroimaging studies in cases with changes of neurological signs are crucial.