Novel Inactivating Homozygous PAPSS2 Mutation in Two Siblings With Disproportionate Short Stature

BACKGROUND/OBJECTIVE: Variants in PAPSS2 (3′-phosphoadenosine 5′-phosphosulfate synthetase 2) present with varying degrees of brachyolmia (short trunk, platyspondyly, mild long-bone abnormalities). Our objective is to present the phenotype of male and female siblings with the same novel inactivating variant in PAPSS2. CASE REPORT: A Jordanian female (case 1), born to consanguineous parents, was referred at 10 years of age for short stature (SS). She had a normal laboratory workup, including normal growth hormone stimulation testing. Spinal x-rays done for clinical scoliosis revealed platyspondyly. She attained an adult height of 143.5 cm (-3 SD). Years later, her brother (case 2) was referred at 21 months of age for SS. His laboratory workup and bone age were normal. His growth velocity declined at 6 years of age, but normal growth factors did not suggest growth hormone deficiency. When he returned during puberty, disproportionate body measurements were noted. A skeletal survey revealed platyspondyly, increasing suspicion of growth plate pathology. Exome sequencing in the family revealed a homozygous variant, p.His496Pro (H496P) in PAPSS2 (NM_004670.3:c.1487A>C). Both parents carried the same variant. DISCUSSION: PAPSS2 assists with the sulfonation of dehydroepiandrosterone (DHEA) to DHEA sulfate and the sulfonation of proteoglycans in the cartilage, necessary for endochondral bone formation. PAPSS2-inactivating variants present with skeletal dysplasia and elevated DHEA levels. CONCLUSION: This novel variant in PAPSS2 manifested with mild brachyolmia but disproportionate SS in male and female siblings. Biochemical phenotype with low circulating DHEA sulfate and high DHEA levels reflect a sulfonation defect.