Objectives: To assess kidney function and clinical features of renal involvement in tuberous sclerosis complex (TSC), including glomerular filtration rate (GFR), albuminuria, and blood pressure (BP) levels in children, adolescents and young adults.

Methods: Patients with a confirmed TSC diagnosis followed up at the Paediatric Neurology department of a tertiary hospital were included in the current cross-sectional study. All participants had kidney imaging within six months of ambulatory blood pressure and GFR assessment. Data on demographics, history, genotype, kidney function at diagnosis and last imaging were also collected.

Results: The median age of the patients was 15 years (IQR range 9 to 18). 23.5% of the participants had ambulatory BP hypertension. Significant positive association of GFR_DTPA with systolic BP values was noted despite the absence of hyperfiltration. Greater increase in GFR from initial TSC diagnosis to assessment date resulted in higher GFR levels in childhood and adolescence in those that developed hypertension and possibly in those with angiomyolipoma or cysts. All patients with ambulatory BP hypertension had angiomyolipomas or cysts on renal imaging studies.

Conclusions: Hypertension may be prevalent in young patients with TSC-related kidney disease. Routine ambulatory BP measurement could be part of the annual clinical assessment of the TSC population.