ATR and nevoid basal cell carcinoma syndrome: Interestingly, the genes responsible for MPDs are often involved in pathways closely related to the MCPH genes: PCNT, encoding a centrosomal protein interacting with MCPH1, is associated with Meier–Gorlin syndrome, while most Seckel syndrome patients display variants in ATR, encoding a modulator of DNA damage response acting downstream of MCPH1.