Raising awareness of TBC1 domain-containing kinase (TBCK) epileptic encephalopathy among Puerto Rican children.

Background: TBC1 domain-containing kinase (TBCK) syndrome is a rare autosomal recessive genetic disorder that presents with infantile hypotonia, intellectual disability, motor impairment, and drug-resistant epilepsy. The abnormal TBCK protein alters the mammalian target of rapamycin complex 1 (mTORC1), leading to accumulation of autophagic vesicles within fibroblasts. Thirty-five previously reported individuals with TBCK were identified. Methods: We present four children with TBCK due to the p.R126X (p.ARG126*) mutation, a variant predominating among children of Puerto Rican descent. This mutation has been associated with TBCK-encephaloneuropathy or Boricua syndrome. Discussion: These four of our patients were diagnosed within a span of 6 months, suggesting that the prevalence of the syndrome could be higher than expected among individuals from Puerto Rico. We believe this finding was largely due to the increasing availability and affordability of modern genetic testing in Puerto Rico, illustrating the importance of equitable access to genetic testing to all pediatric patients with similar symptomatology. Prompt diagnosis facilitates appropriate medical management and prognosis counseling.