Medical intervention in a constitutionally tall child.

Constitutionally tall stature (CTS) in children is a normal variant of growth within populations. Based mainly on psychological factors, sex steroids have been prescribed since the 1950s to induce puberty, as a mean to reduce final adult height. Controversy remains in the treatment of CTS, as well as lack of established criteria for initiating treatment.

Mutation of the CYP2R1 vitamin D 25-hydroxylase in a Saudi Arabian family with severe vitamin D deficiency.

Context: Inherited forms of vitamin D deficiency are rare causes of rickets and to date have been traced to mutations in three genes, VDR, encoding the 1α,25-dihydroxyvitamin D receptor, CYP27B1, encoding the vitamin D 1α-hydroxylase, and CYP2R1, encoding a microsomal vitamin D 25-hydroxylase.

Results: Multiple mutations have been identified in VDR and CYP27B1 in patients with rickets, and thus, the roles of these two genes in vitamin D metabolism are unassailable. The case is less clear for CYP2R1, in which only a single mutation, L99P in exon 2 of the gene, has been identified in Nigerian families, and because multiple enzymes with vitamin D 25-hydroxylase activity have been identified.