MCPH1, also known as BRIT1, serves as a multifaceted guardian of genomic integrity by promoting DNA damage sensing and repair, enforcing the G2/M checkpoint, limiting centrosome amplification, and stabilizing p53 through inhibition of MDM2-mediated ubiquitination; such functions plausibly link MCPH1 deficiency to genomic instability and cell cycle dysregulation in MM (45–47). This evidence concerns the gene TP53 and Miyoshi myopathy.