Infantile systemic hyalinosis is an autosomal recessive disease characterized by severe progressive flexion contractures, multiple recurring subcutaneous tumours, and gingival hypertrophy. It is caused by mutations in the gene encoding capillary morphogenesis protein-2 (CMG2). Here we report a Saudi infant with infantile systemic hyalinosis who presented with intractable diarrhea, and we review the literature emphasizing recent developments in the molecular genetics of this disease.