A case of carbonic anhydrase type VA deficiency presenting as West syndrome in an infant with a novel mutation in the CA-VA gene

Carbonic anhydrase VA (CA-VA) deficiency is a rare autosomal-recessive inborn error of metabolism. It is imperative to consider CA-VA deficiency as a differential diagnosis in neonates with hyperammonemia not attributed to defects in urea cycle enzymes, organic acid disorders, hypoglycemia, and primary hyperlactatemia. The case described in this report had a metabolic crisis on day three of life with biochemical abnormalities demonstrating hypoglycemia, elevated ammonia, and lactate. At eight months, he presented with developmental delay and infantile spasms. Considering the history of consanguinity and infantile spasms, clinical exome sequencing was done, which revealed a pathogenic novel mutation suggestive of CA-VA deficiency. On review of the literature, we found that about 21 affected individuals have been reported to date. Unprovoked seizures or epilepsy have not yet been described in CA-VA deficiency. This report expands the phenotypic spectrum of neurological manifestations of CA-VA deficiency and adds to the existing number of cases in the reported literature.