Based on limited published evidence, SPACA5 is an X-linked gene encoding a sperm acrosome-associated protein with annotated roles in acrosomal vesicle organization, sperm-egg fusion during fertilization, and lysozyme activity. The gene localizes to the sperm flagellum. A 335.4 kb microduplication encompassing SPACA5 on chromosome X.2p11.3 was identified in a patient with developmental delay, autistic features, and growth retardation 1, though the pathogenic contribution of SPACA5 overexpression remains unclear as the primary candidate gene in this region is ZNF81.