Charcot-Marie-Tooth disease (CMT) constitutes a large group of genetically 
heterogeneous disorders of the peripheral nervous system. Autosomal recessive 
forms of CMT are less common in the general population but account for the vast 
majority of CMT phenotypes in communities with a high prevalence of 
consanguinity. At least 10 genetic loci cause autosomal recessive forms of CMT. 
Mutations in the ganglioside-induced differentiation-associated protein 1 
(GDAP1) gene are among the most frequent genetic causes of autosomal recessive 
forms of CMT. To date, 28 mutations in GDAP1 gene have been linked with the 
disease. Here, we report a novel GDAP1 mutation in an Old Order Amish family 
with CMT. To ascertain the Amish CMT locus, we performed a genome-wide single 
nucleotide polymorphism (SNP) analysis on one of three patients from a 
consanguineous pedigree. Assuming mutation homogeneity, the analysis sought 
large homozygous SNP blocks that also contained known CMT loci. The largest 
homozygous SNP block in the patient was localized to chromosome 8q13.1-21.3 and 
contained the GDAP1 gene. Sequence analysis revealed a novel homozygous 
mutation, c.692C>T, at codon 231 (p.P231L) in exon 5 of GDAP1 in all patients. 
Neither the unaffected individuals in the family nor the healthy control samples 
were homozygous for this mutation. Our findings suggested that this novel 
mutation in GDAP1 gene is associated with an autosomal recessive form of CMT in 
Ohio Old Order Amish community.