AICA-ribosiduria

AICA-ribosiduria (also known as AICAR transformylase/IMP cyclohydrolase deficiency) is an extremely rare inborn error of purine metabolism caused by a deficiency of the bifunctional enzyme ATIC (5-aminoimidazole-4-carboxamide ribonucleotide transformylase/inosine monophosphate cyclohydrolase), which catalyzes the last two steps of de novo purine biosynthesis. This deficiency leads to accumulation of AICA-riboside (5-aminoimidazole-4-carboxamide riboside) and its phosphorylated form (ZMP/AICAR) in body fluids. The condition is classified under other disorders of purine and pyrimidine metabolism (ICD-10: E79.8). The disease primarily affects the neurological system and manifests in early life. Key clinical features reported include profound intellectual disability, dysmorphic features, congenital blindness, epilepsy, and severe psychomotor delay. Affected individuals may also exhibit congenital malformations. The accumulation of AICAR is thought to interfere with multiple cellular processes, contributing to the multisystem manifestations observed. AICA-ribosiduria is one of the rarest known metabolic disorders, with only a very small number of cases described in the medical literature. Diagnosis is based on the detection of elevated AICA-riboside in urine and can be confirmed by molecular analysis of the ATIC gene located on chromosome 2q35. There is currently no specific curative treatment available. Management is supportive and symptomatic, focusing on seizure control, developmental support, and management of associated complications.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about AICA-ribosiduria