SLC26A2 and achondrogenesis type IB: Mutations in the SLC26A2 result in a family of skeletal dysplasias depending on the residual sulfate transporter activity, which range in severity from the very severe achondrogenesis type IB (MIM 600972) [9], atelosteogenesis type II (MIM 256050) [10], and diastrophic dysplasia (MIM 222600) [11] to the relatively mild recessive multiple epiphyseal dysplasia-4 (MED-4, MIM 226900).