Recurrent hyperammonaemia in a patient with carbonic anhydrase VA deficiency

Abstract

Carbonic anhydrase VA deficiency is a recently described inherited cause of paediatric hyperammonaemia. Most published cases describe patients with only one episode of hyperammonaemia whilst others report patients who had up to three metabolic crises with the first invariably being the most severe. We describe a patient with carbonic anhydrase VA deficiency who experienced 7 hyperammonemic episodes over a 3‐year period, up to age 5 years 9 months. These episodes did not clearly decrease in severity over time. This report expands the clinical phenotype and the age window for metabolic crises associated with this condition.

A founder mutation in CA5A causing intrafamilial and interfamilial phenotypic variability in a cohort of 18 patients with carbonic anhydrase VA deficiency

“…Although earlier published studies suggest that patients affected with CA‐VA deficiency usually do not develop further episodes of hyperammonemia beyond the first episode that brings them to medical attention, 1 recurrence of hyperammonemia was reported in a patient with CA‐VA deficiency who experienced seven hyperammonemic episodes over a 3‐year period, up to age of 5 years 9 months 11 . In agreement with this observation, 7/18 patients have developed recurrent hyperammonemia in the context of physiologic stress exemplified with febrile illness or acute gastroenteritis; 11/18 indeed experienced no further episodes of hyperammonemia in agreement with the previously published observations.…”