Molecular diagnosis of TSC is mainly performed by next-generation sequencing (NGS) using TSC1 and TSC2 panels, and although copy number variants (CNV) analysis used to be performed mainly by multiplex ligation-dependent probe amplification (MLPA) (Rosset et al., 2017), more recent protocols include CNV in the NGS analysis (Singh et al., 2021). The gene discussed is TSC2; the disease is tuberous sclerosis.