These data highlight the need for detailed mRNA expression, splicing studies, and protein analysis to establish how individual mutations affect the normal and cryptic splicing of CENPJ mRNAs for each patient directly, and not with prediction analysis tools, so as to understand why some CENPJ mutations cause microcephaly and others Seckel syndrome and how the same CENPJ mutation can cause clinical heterogeneity [4]. This evidence concerns the gene CPAP and microcephalic primordial dwarfism.