Hereditary Vitamin D-Resistant Rickets in Lebanese Patients: The p.R391S and p.H397P Variants Have Different Phenotypes
TLDR Two different mutations in the vitamin D receptor gene cause different symptoms and responses to treatment in Lebanese patients with hereditary rickets.
In a study from 2017, researchers investigated hereditary vitamin D-resistant rickets (HVDRR) in four patients from three unrelated Lebanese families, all with consanguineous parents displaying a normal phenotype. They identified two homozygous mutations, p.R391S and p.H397P, in exon 9 of the vitamin D receptor (VDR) gene using Sanger sequencing. The study found that alopecia was associated only with the p.R391S mutation, and despite similar rachitic bone disease, patients exhibited different responses to high doses of alfacalcidol (1-α-hydroxy vitamin D3) supplementation. This marked the first report of VDR mutations in Lebanon and suggested promising clinical outcomes despite the severity of the phenotypes.
