While the proportion of PLCs in non-transduced cells (16%) or in cells expressing GFP alone (21%) was typical for PCC syndrome, cells expressing MCPH1-FL, Δe9–14, or Δe8 exhibited a reduced number of PLCs (0.3%–1.3%) in the normal range. The gene discussed is MCPH1; the disease is microcephaly 1, primary, autosomal recessive.