[show abstract][hide abstract] ABSTRACT: Both peripheral neuropathy and distal myopathy are well-established inherited neuromuscular disorders characterized by progressive weakness and atrophy of the distal limb muscles. A complex phenotype of peripheral neuropathy, myopathy, hoarseness, and hearing loss was diagnosed in a large autosomal dominant Korean family. A high density single nucleotide polymorphism (SNP)-based linkage study mapped the underlying gene to a region on chromosome 19q13.3. The maximum multipoint LOD score was 3.794. Sequencing of 34 positional candidate genes in the segregating haplotype revealed a novel c.2822G>T (p.Arg941Leu) mutation in the gene MYH14, which encodes the nonmuscle myosin heavy chain 14. Clinically we observed a sequential pattern of the onset of muscle weakness starting from the anterior to the posterior leg muscle compartments followed by involvement of intrinsic hand and proximal muscles. The hearing loss and hoarseness followed the onset of distal muscle weakness. Histopathologic and electrodiagnostic studies revealed both chronic neuropathic and myopathic features in the affected patients. Although mutations in MYH14 have been shown to cause nonsyndromic autosomal dominant hearing loss (DFNA4), the peripheral neuropathy, myopathy, and hoarseness have not been associated with MYH14. Therefore, we suggest that the identified mutation in MYH14 significantly expands the phenotypic spectrum of this gene.
Human Mutation 06/2011; 32(6):669-77. · 5.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: Both the myotonic dystrophy type 1 (DM1) and the X-linked dominant Charcot-Marie-Tooth disease (CMTX1) are well-established inherited neuromuscular disorders characterized by progressive weakness and atrophy of the distal limb muscles. The underlying causes of the DM1 and CMTX1 are mutations in the DMPK and GJB1 gene, respectively. A patient with both DM1 and CMTX1 inherited these from his father and mother, respectively. Histopathological and electrodiagnostic studies revealed both chronic neuropathic and myopathic features. Physical disabilities were more severe than seen with either DM1 or CMTX1 alone. In addition, the present case reveals an asymmetric atrophy (22%) of the right calf muscle compared to the left side.
[show abstract][hide abstract] ABSTRACT: Charcot-Marie-Tooth disease (CMT) is classified into demyelinating neuropathy (CMT1) and axonal neuropathy (CMT2). Mutations
in the neurofilament light chain polypeptide (NEFL) gene are present in CMT2E and CMT1F neuropathies. Two types of Pro22 mutations have been previously reported: Pro22Ser in
CMT2E with giant axons, and Pro22Thr in CMT1F. In this study, we identified another Pro22 mutation, Pro22Arg, in a Korean
CMT1 family. An investigation to identify the clinical and pathological characteristics of the Pro22Arg revealed that it is
associated with demyelinating neuropathy features in CMT1F. Histopathological findings showed onion bulb formations but no
giant axons. It appears that the Pro22 mutations may influence not only the Thr-Pro phosphorylation site by proline-directed
protein kinases but also other structural alteration of the NEFL protein in a different way.
Journal of Human Genetics 09/2008; 53(10):936-940. · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Distal hereditary motor neuropathy (dHMN) is a heterogeneous disorder characterized by degeneration of motor nerves in the absence of sensory abnormalities. Recently, mutations in the small heat shock protein 27 (HSP27) gene were found to cause dHMN type II or Charcot-Marie-Tooth disease type 2F (CMT2F). The authors studied 151 Korean axonal CMT or dHMN families, and found a large Korean dHMN type II family with the Ser135Phe mutation in HSP27. This mutation was inherited in an autosomal dominant manner, and was well associated with familial members with the dHMN phenotype. This mutation site is located in the alpha-crystallin domain and is highly conserved between different species. The frequency of this HSP27 mutation in Koreans was 0.6%. Magnetic resonance imaging analysis revealed that fatty infiltrations tended to progressively extend distal to proximal muscles in lower extremities. In addition, fatty infiltrations in thigh muscles progressed to affect posterior and anterior compartments but to lesser extents in medial compartment, which differs from CMT1A patients presenting with severe involvements of posterior and medial compartments but less involvement of anterior compartment. The authors describe the clinical and neuroimaging findings of the first Korean dHMN patients with the HSP27 Ser135Phe mutation. To our knowledge, this is the first report of the neuroimaging findings of dHMN type II.
Experimental and Molecular Medicine 07/2008; 40(3):304-12. · 2.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: A wide range of phenotypes have been reported in autosomal recessive (AR) Charcot-Marie-Tooth disease (CMT) patients carrying mutations in the ganglioside-induced differentiation-associated protein 1 (GDAP1) gene, such as axonal, demyelinating, and intermediate forms of AR CMT. There have been very few reports of GDAP1 mutations in autosomal dominant (AD) CMT. Here, we report an AD CMT family with a novel Q218E mutation in the GDAP1 gene. The mutation was located within the well-conserved glutathione S-transferase (GST) core region and co-segregated with the affected members in the pedigree. The affected AD CMT individuals had a later disease onset and much milder phenotypes than the AR CMT patients, and the histopathologic examination revealed both axonal degeneration and demyelination.
Journal of Human Genetics 02/2008; 53(4):360-4. · 2.37 Impact Factor