Deletion of the serine 34 codon from the major peripheral myelin protein P0 gene in Charcot–Marie–Tooth disease type 1B

Charcot–Marie–Tooth disease type 1B (CMT1B) is genetically linked to chromosome 1q21–23. The major peripheral myelin protein gene, P 0 , has been cloned and localized to the same chromosomal region. P 0 is a 28 kDa glycoprotein involved in the compaction of the multilamellar myelin sheet and accounts for more than half of the peripheral myelin protein content. We checked whether P 0 is altered in CMT1B, and show here that a 3 basepair deletion in exon 2 of the P 0 gene is present in all affected individuals of a CMT1B family. The mutation results in the deletion of serine 34 in the extracellular domain of P 0 , suggesting that alterations of P 0 cause CMT1B.