[Tuberous sclerosis: clinical characteristics and their relationship to genotype/phenotype]

Introduction: Tuberous sclerosis (TS) is an inherited disorder with multisystemic involvement and a high phenotypic variability. There are two genes that cause this condition: TSC1 and TSC2.

Objectives: Our goal was to clinically characterize patients with TS followed up in the Pediatric Neurology Clinic of a tertiary hospital during the last 10 years, and correlate the genotype with the severity of neurological manifestations and imaging studies.

Patients and methods: Retrospective analysis of patients with TS, including review of medical records and available MRI imaging.

Results: We studied 35 cases with a median age at diagnosis of ten months. Seizures were the first manifestation in 91.4% of cases, with a predominance of epileptic spasms. Over 50% had cognitive impairment and 49% behavioral disorders. A genetic study was performed on 24 children, and TSC2 mutations identified in 58.3% of them. Of the 11 cases of refractory epilepsy, six had the TSC2 gene mutation. In the group of eight patients with moderate/severe cognitive deficits, five had TSC2 mutations. We reviewed 26 MRI scans, in which it was observed that 76.9% had diffuse involvement of cerebral lobes, which reflects a greater burden of injury. Of the patients who had an MRI scan performed and had TSC2 mutations, all had a high tuber load, and5 of them had refractory epilepsy.

Discussion: In our sample we observe a high percentage of mutations in the TSC2 gene. This mutation carries a worse neurological prognosis, with drug-resistant epilepsy and a more severe cognitive impairment.