[A case of Charcot-Marie-Tooth disease 1 B with Val 146Phe mutation of myelin protein zero showing a severe clinical phenotype].
A 15-year-old boy had complaints of progressive gait disturbance and foot deformity. He started to walk at the age of 18 months. Since two years of age, he had noticed unstable gait. He showed evident scoliosis and enlarged great auricular nerves. Moderate to slight degrees of muscular atrophy and weakness of distal upper, and proximal and distal lower limbs were observed. Pes equinovarus deformity of both feet was obvious. Muscle stretch reflexes were absent in both limbs except decreased triceps brachii reflex. Vibratory sensation was decreased severely in the toes and mildly in the fingers. In cerebrospinal fluid, protein was mildly elevated. Median nerve motor conduction velocity was 5.0 m/sec. On sural nerve biopsy, both demyelinated and remyelinated axons and onion-bulbs without hypomyelination were observed. Therefore, the diagnosis of Charcot-Marie-Tooth disease 1 was made. The direct sequencing of the genomic DNA encoding the Po gene revealed a mutant allele, a guanine to thymine substitution of nucleotide position 436, which caused a substitution of phenylalanine for valine at amino acid position 146. This type of Po mutation is different from any type of Po mutation reported in the literature.
Ohnishi
A
A
Aoki
A
A
Yamamoto
T
T
Tsuji
S
S
D000293:Adolescent; D019943:Amino Acid Substitution / Q000235:genetics; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D018993:Myelin P0 Protein / Q000235:genetics*; D009431:Neural Conduction; D010525:Peripheral Nerves / Q000473:pathology; D010649:Phenylalanine; D017354:Point Mutation; D012720:Severity of Illness Index; D014633:Valine
D018993:Myelin P0 Protein; D010649:Phenylalanine; D014633:Valine