RP1 and hypoparathyroidism-retardation-dysmorphism syndrome: In the framework of a screening effort of 331 unrelated Japanese patients, we identified a novel, unusual mutation by whole-genome sequencing, consisting in the insertion of a mobile Alu element in exon 4 of the RP1 gene (m1, or NM_006269.1:c.4052_4053ins328/p.Tyr1352Alafs*9) in a female individual from a recessive HRD family.