RRP7A is a nucleolar protein with dual roles in ribosome biogenesis and cellular development. Primary function: RRP7A participates in ribosomal RNA (rRNA) processing as a component of the small subunit (SSU) processome, the initial precursor of eukaryotic small ribosomal subunits 1. Within this complex, RRP7A works with ribosome biogenesis factors and RNA chaperones to facilitate RNA folding, modifications, rearrangements, and degradation of pre-rRNA 2. Mechanism: RRP7A localizes to centrosomes, cilia, and nucleoli 1. Beyond ribosome biogenesis, it functions in primary cilia resorption and cell cycle progression during neurogenesis and neocortex development 1. Disease relevance: RRP7A mutations cause microcephaly-28, an autosomal recessive primary microcephaly characterized by reduced brain size and intellectual disability 1. The pathophysiology involves defects in neuronal progenitor function, with patient-derived fibroblasts showing impaired rRNA processing, abnormal primary cilia resorption, and compromised cell cycle progression 1. Zebrafish models confirm that patient mutations reduce brain size and impair neurogenesis and cell proliferation 1. Clinical significance: RRP7A dysfunction links fundamental ribosomal biogenesis defects to neurodevelopmental pathology, elucidating mechanisms of primary microcephaly and highlighting potential therapeutic targets for this developmental disorder.