The correlation of intracranial parenchymal calcium score and the severity of neurological clinical presentation in carbonic anhydrase deficiency type 2.

Background: Carbonic anhydrase type II deficiency (CAII-D) syndrome is a rare autosomal recessive genetic disorder characterized by osteopetrosis, renal tubular acidosis, and brain calcifications. Understanding the clinical and radiological features of CAII-D is key to effective management.

Aim: This study aimed to comprehensively analyze and measure intracranial parenchymal calcium score in pediatric CAII-D in relation to the severity of neurological clinical presentation.

Methods: A retrospective chart review at King Saud University Medical City included pediatric CAII-D patients diagnosed between June 2015 and December 2022. Study variables included age, gender, genetic results, developmental status, developmental quotient (DQ), CT findings, optic canal diameter, intracranial calcium score, and neuropsychiatric symptoms.

Results: Ten CAII-D patients, median age 10.5 years, were included. Most patients displayed homozygous pathogenic CA2 gene variants. For neurodevelopmental symptoms, 60.0 % of patients presented with global developmental delay, 20.0 % had intellectual disability, and the remaining 20.0 % had normal development. The median DQ score was 63.50, with 80.0 % categorized as delayed. Neuropsychiatric disorders were present in 20.0 %. Optic nerve atrophy was observed in 22.2 %, while brain calcifications were present in 70.0 % of cases. Correlation analysis revealed no significant associations between intracranial parenchymal calcium score and age, DQ score, or optic canal diameter. Neurodevelopmental symptoms, neuropsychiatric symptoms, and DQ were not associated with intracranial parenchymal calcium score.

Conclusion: Intraparenchymal calcifications in CAII-D are common but unrelated to developmental delay and neuropsychiatric symptoms, suggesting complex pathophysiology. Follow-up brain imaging may not aid in prognosis or severity assessment, highlighting the need for further research.