INTRODUCTION: Inherited Manganism (IMn) is an inborn error of manganese (Mn) homeostasis. This unusual entity is comprised by polycythaemia, movement disorders, liver cirrhosis, hypermanganesaemia, and peculiar hyperintense signal in the basal ganglia in the T1-weighted sequence of MRI.

CASE DESCRIPTION: An 11-year-old girl with uneventful development until the age of 7 years, when presented progressive cognitive impairment and limb dystonia. Furthermore, she had polycythemia, chronic liver disease and high levels of serum manganese. MRI disclosed bilateral hyperintense signal in the basal ganglia, midbrain and cerebellar nuclei in the T1-weighted sequence, suggesting Mn storage (figure). It was detected mutations in SLC30A10, accountable for a manganese transporter.

DISCUSSION: IMn is an inborn error caused by mutations in the Mn transporter gene SLC30A10. It’s characterized by hepatic cirrhosis, polycythemia,  hypermanganesaemia, and a severe syndrome extrapyramidal. Typical brain MRI in IMn comprises: hyperintense signal in the globus pallidus on T1-weighted sequences, with changes extending into adjacent basal ganglia in most cases. White matter involvement may also be observed. T2 changes of low signal return from the globus pallidus are also present. Treatment includes chelating therapy and iron supplementation.