The infantile form of VPS33A‐related mucopolysaccharidosis plus disease manifests in the first year of life with delayed psychomotor development, failure to thrive, diffuse muscle hypotonia, joints contractures, dysostosis multiplex, and rapid progression of multisystem disease affecting respiratory, immune, cardiovascular, hematological, gastrointestinal, renal, and central nervous systems. The gene discussed is VPS33A; the disease is mucopolysaccharidosis.