A new point mutation affecting the fourth transmembrane domain of PMP22 results in severe de novo Charcot-Marie-Tooth disease.
A novel T-->G mutation in exon 4 of the PMP22 gene was identified heterozygously in a girl with severe, de novo CMT1A disease. Duplication of the chromosomal 17p11-12 region, encompassing the PMP22 gene, was ruled out. This is the only known mutation that specifically affects the human fourth transmembrane (TM) domain of PMP22. It results in a substitution of a non-polar amino acid by a polar one (Leu147-->Arg), similar to the nearby Gly150-->Asp substitution, underlying the severe Trembler phenotype in the mouse. These mutations suggest that the fourth TM domain plays a crucial role in the normal function of PMP22. The new mutation also augments previous observations that diseases caused by mutations in PMP22 are more severe than those caused by the duplication of 17p11-12.
Navon
R
R
Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Israel.
Seifried
B
B
Gal-On
N S
NS
Sadeh
M
M
D000595:Amino Acid Sequence; D001120:Arginine; D001224:Aspartic Acid; D001483:Base Sequence; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics*; D002648:Child; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification; D005091:Exons; D005260:Female; D006580:Genetic Carrier Screening; D005819:Genetic Markers; D005998:Glycine; D006801:Humans; D007930:Leucine; D008297:Male; D008969:Molecular Sequence Data; D005810:Multigene Family; D009185:Myelin Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010375:Pedigree; D017354:Point Mutation
D005819:Genetic Markers; D009185:Myelin Proteins; C073687:PMP22 protein, human; C489545:Pmp22 protein, mouse; D001224:Aspartic Acid; D004247:DNA; D001120:Arginine; D007930:Leucine; D005998:Glycine