SLC13A1 and skeletal dysplasia: To our knowledge, this is the first functional and phenotypic characterization of SLC13A1 variants identified in a cohort of children with skeletal dysplasia and biallelic variants in SLC13A1. This genetic disorder is associated with a measurable biomarker in the blood (hyposulfatemia) and urine (hypersulfuria) that ultimately results in abnormal cartilage and bone development and possibly other clinical phenotypes that have yet to be fully recognized.