Incidence of tuberous sclerosis and age at first diagnosis: new data and emerging trends from a national, prospective surveillance study

Daniel Ebrahimi-Fakhari, Lilian Lisa Mann, Martin Poryo, Norbert Graf, Rüdiger von Kries, Beate Heinrich, Darius Ebrahimi-Fakhari, Marina Flotats-Bastardas, Ludwig Gortner, Michael Zemlin, Sascha Meyer

Tuberous Sclerosis Complex (TSC) is a rare multisystem disorder. In 2012 diagnostic criteria for TSC were revised. However, data on the incidence of TSC are limited. Prospective, national surveillance study in Germany over a 2-year-period (03/2015-02/2017) using current revised criteria for TSC. Patients up to the age of 18 years with a new diagnosis of definite or possible TSC (clinical and/or genetic) were included. The aims of this study were 1) to generate up-to-date data on the incidence of definite or possible TSC, 2) to assess age at first diagnosis, and 3) to compare these data with previous epidemiologic data. In total, 86 patients met inclusion criteria (definite or possible TSC) with a median age at diagnosis of 6 months (range: 5 months before birth - 197 months of age). Among patients identified with features of TSC, 73.3% met criteria for definite diagnosis (median age: 7 months) and 26.7% met criteria for a possible diagnosis (median age: 3 months). 55.8% of patients were male. When excluding prenatally diagnosed patients, median age at diagnosis was 11 months with a range of 0 to 197 months. The 3 most common clinical features at diagnosis of TSC were central nervous system involvement in 73.3% patients (of these 95.2% experienced seizures), cutaneous involvement in 58.1% patients (with the most common lesion being hypomelanotic macules in 92%) and cardiac rhabdomyoma in half of the patients. Cardiac rhabdomyoma were detected by prenatal ultrasonography in 22.1% of patients. The presence of cardiac rhabdomyoma was associated with cardiac arrhythmias in 25.6% (about 13% of all diagnosed patients) in our cohort. The overall prevalence of seizure disorders was 69.8%. The annual incidence rate of TSC is estimated at a minimum of 1:17.785 live births. However correcting for underreporting, the estimated incidence rate of definite or possible TSC is approximately 1:6.760-1:13.520 live births in Germany. This is the first study that assessed prospectively the incidence rate of TSC in children and adolescents using the updated diagnostic criteria of 2012. This prospective surveillance study demonstrates a low age at first diagnosis (median: 6 months), likely due to antenatal detection of cardiac rhabdomyoma. Early diagnosis bears the potential for implementing effective therapies at an earlier stage.