PWP2 encodes a WD repeat-containing protein that functions as a component of the small subunit (SSU) processome, which is involved in ribosomal biogenesis 1. The protein localizes to the dense fibrillar component and granular component regions of nucleoli, where it participates in the assembly and maturation of the small ribosomal subunit 1. PWP2 shows low mobility in living cells and binds tightly to macro-protein complexes, suggesting it acts as a scaffold or core component within nucleolar complexes 1. The gene is located on chromosome 21.3 and consists of 21 exons spanning approximately 24-25 kb 23. PWP2 is ubiquitously expressed in all fetal and adult human tissues as a 3.3-3.4 kb transcript 43. The protein shows 42% identity to yeast PWP2 and belongs to the WD repeat-containing superfamily 3. Recent studies have identified PWP2 as a potential candidate gene for neurodevelopmental disorders, particularly those involving microcephaly, with variants potentially affecting cell cycle and division processes 5. The gene's location in the 21q22.3 region makes it a candidate for genetic disorders mapping to this chr21 region 2.