To the Editor We read with great interest the report by Fahiminiya and colleagues on the involvement of WNT1 in the pathogenesis of autosomal recessive osteogenesis imperfecta (OI).1 The identification of WNT1 as a novel OI gene by several groups was not guided by the knockout mouse phenotype but rather based on the use of next generation sequencing.1–3 However, the phenotype described for Wnt1−/− was that of early postnatal lethality due to severe central nervous system (CNS) involvement and Wnt1 expression was thought to be exclusive to the brain and testis.4 Curiously, none of the patients described by the three groups displayed significant CNS phenotype.

In this letter, we describe a novel WNT1 mutation in …