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

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.

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.

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.

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.