Background: Vitamin D-dependent rickets type 1 A (VDDR1A) is an autosomal recessive disorder due to mutations in the CYP27B1 gene which result in inability to generate 1,25(OH)D.
Case Presentation: An 18-month-old boy with VDDR1A presented with hypotonia and respiratory distress. He had been diagnosed 2 months earlier, having been evaluated for stunted growth, hypotonia, and delayed developmental milestones.