A Mutation in PMP2 Causes Dominant Demyelinating Charcot-Marie-Tooth Neuropathy.

Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of peripheral neuropathies with diverse genetic causes. In this study, we identified p.I43N mutation in PMP2 from a family exhibiting autosomal dominant demyelinating CMT neuropathy by whole exome sequencing and characterized the clinical features. The age at onset was the first to second decades and muscle atrophy started in the distal portion of the leg. Predominant fatty replacement in the anterior and lateral compartment was similar to that in CMT1A caused by PMP22 duplication. Sural nerve biopsy showed onion bulbs and degenerating fibers with various myelin abnormalities. The relevance of PMP2 mutation as a genetic cause of dominant CMT1 was assessed using transgenic mouse models. Transgenic mice expressing wild type or mutant (p.I43N) PMP2 exhibited abnormal motor function. Electrophysiological data revealed that both mice had reduced motor nerve conduction velocities (MNCV). Electron microscopy revealed that demyelinating fibers and internodal lengths were shortened in both transgenic mice. These data imply that overexpression of wild type as well as mutant PMP2 also causes the CMT1 phenotype, which has been documented in the PMP22. This report might expand the genetic and clinical features of CMT and a further mechanism study will enhance our understanding of PMP2-associated peripheral neuropathy.

Sleep Related Problems as a Nonmotor Symptom of Dentatorubropallidoluysian Atrophy.

Dentatorubropallidoluysian atrophy (DRPLA) is a neurodegenerative disease caused by an expansion of a cytosine-adenine-guanine (CAG) repeat encoding a polyglutamine tract in the atrophin-1 protein. Unlike other CAG repeat diseases, sleep related problems have not been reported in patients with DRPLA. There was a 65-year-old man and his family with DRPLA. They suffered from seizure, gait disturbance, and cognitive decline. The patients commonly showed dream enacting sleep disorder, insomnia. The results from overnight polysomnography showed rapid eye movement (REM) without atonia in patients with DRPLA. The man died 2 years after diagnosis and was subjected for brain autopsy. We report REM sleep behavior disorders in patients with DRPLA confirmed with polysomnography with pathological description of the patient.

DGAT2 Mutation in a Family with Autosomal-Dominant Early-Onset Axonal Charcot-Marie-Tooth Disease.

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy and is a genetically and clinically heterogeneous disorder. We examined a Korean family in which two individuals had an autosomal-dominant axonal CMT with early-onset, sensory ataxia, tremor, and slow disease progression. Pedigree analysis and exome sequencing identified a de novo missense mutation (p.Y223H) in the diacylglycerol O-acyltransferase 2 (DGAT2) gene. DGAT2 encodes an endoplasmic reticulum-mitochondrial-associated membrane protein, acyl-CoA:diacylglycerol acyltransferase, which catalyzes the final step of the triglyceride (TG) biosynthesis pathway. The patient showed consistently decreased serum TG levels, and overexpression of the mutant DGAT2 significantly inhibited the proliferation of mouse motor neuron cells. Moreover, the variant form of human DGAT2 inhibited the axonal branching in the peripheral nervous system of zebrafish. We suggest that mutation of DGAT2 is the novel underlying cause of an autosomal-dominant axonal CMT2 neuropathy. This study will help provide a better understanding of the pathophysiology of axonal CMT and contribute to the molecular diagnostics of peripheral neuropathies.

Charcot-Marie-Tooth Disease Type 4H Resulting from Compound Heterozygous Mutations in FGD4 from Nonconsanguineous Korean Families.

Charcot-Marie-Tooth disease type 4H (CMT4H) is an autosomal recessive demyelinating subtype of peripheral enuropathies caused by mutations in the FGD4 gene. Most CMT4H patients are in consanguineous Mediterranean families characterized by early onset and slow progression. We identified two CMT4H patients from a Korean CMT cohort, and performed a detailed genetic and clinical analysis in both cases. Both patients from nonconsanguineous families showed characteristic clinical manifestations of CMT4H including early onset, scoliosis, areflexia, and slow disease progression. Exome sequencing revealed novel compound heterozygous mutations in FGD4 as the underlying cause in both families (p.Arg468Gln and c.1512-2A>C in FC73, p.Met345Thr and c.2043+1G>A (p.Trp663Trpfs*30) in FC646). The missense mutations were located in highly conserved RhoGEF and PH domains which were predicted to be pathogenic in nature by in silico modeling. The CMT4H occurrence frequency was calculated to 0.7% in the Korean demyelinating CMT patients. This study is the first report of CMT4H in Korea. FGD4 assay could be considered as a means of molecular diagnosis for sporadic cases of demyelinating CMT with slow progression.

A novel homozygous MPV17 mutation in two families with axonal sensorimotor polyneuropathy.

BACKGROUND: Mutations in MPV17 cause the autosomal recessive disorder mitochondrial DNA depletion syndrome 6 (MTDPS6), also called Navajo neurohepatopathy (NNH). Clinical features of MTDPS6 is infantile onset of progressive liver failure with seldom development of progressive neurologic involvement. METHODS: Whole exome sequencing (WES) was performed to isolate the causative gene of two unrelated neuropathy patients (9 and 13 years of age) with onset of the syndrome. Clinical assessments and biochemical analysis were performed. RESULTS: A novel homozygous mutation (p.R41Q) in MPV17 was found by WES in both patients. Both showed axonal sensorimotor polyneuropathy without liver and brain involvement, which is neurophysiologically similar to axonal Charcot-Marie-Tooth disease (CMT). A distal sural nerve biopsy showed an almost complete loss of the large and medium-sized myelinated fibers compatible with axonal neuropathy. An in vitro assay using mouse motor neuronal cells demonstrated that the abrogation of MPV17 significantly affected cell integrity. In addition, the expression of the mutant protein affected cell proliferation. These results imply that both the loss of normal function of MPV17 and the gain of detrimental effects of the mutant protein might affect neuronal function. CONCLUSION: We report a novel homozygous mutation in MPV17 from two unrelated patients harboring axonal sensorimotor polyneuropathy without hepatoencephalopathy. This report expands the clinical spectrum of diseases caused by mutations of MPV17, and we recommend MPV17 gene screening for axonal peripheral neuropathies.

Recessive C10orf2 mutations in a family with infantile-onset spinocerebellar ataxia, sensorimotor polyneuropathy, and myopathy.

Recessive mutations in chromosome 10 open reading frame 2 (C10orf2) are relevant in infantile-onset spinocerebellar ataxia (IOSCA). In this study, we investigated the causative mutation in a Korean family with combined phenotypes of IOSCA, sensorimotor polyneuropathy, and myopathy. We investigated recessive mutations in a Korean family with two individuals affected by IOSCA. Causative mutations were investigated using whole exome sequencing. Electrophysiological analyses and muscle and nerve biopsies were performed, along with magnetic resonance imaging (MRI) of the brain and lower extremities. Compound heterozygous mutations c.1460C>T and c.1485-1G>A in C10orf2 were identified as causative of IOSCA. Skeletal muscle showed mitochondrial DNA (mtDNA) deletions. Both patients showed a period of normal development until 12-15 months, followed by ataxia, athetosis, hearing loss, and intellectual disability. Electrophysiological findings indicated motor and sensory polyneuropathies. Muscle biopsy revealed variations in the size and shape of myofibers with scattered, small, and angulated degenerating myofibers containing abnormal mitochondria; these observations are consistent with myopathy and may be the result of mtDNA deletions. Sural nerve biopsy revealed an axonal neuropathy. High-signal-intensity lesions in the middle cerebellar peduncles were correlated with clinical severity, and MRI of the lower legs was compatible with the hypothesis of length-dependent axonal degeneration. We identified novel compound heterozygous mutations of the C10orf2 gene as the cause of IOSCA with sensorimotor polyneuropathy and myopathy. Signs of motor neuropathy and myopathy were discovered for the first time in IOSCA patients with C10orf2 mutations. These results suggest that the clinical spectrum of IOSCA caused by C10orf2 mutations may be more variable than previously reported.

A compound heterozygous mutation in HADHB gene causes an axonal Charcot-Marie-tooth disease.

BACKGROUND: Charcot-Marie-Tooth disease (CMT) is a heterogeneous disorder of the peripheral nervous system. So far, mutations in hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), beta subunit (HADHB) gene exhibit three distinctive phenotypes: severe neonatal presentation with cardiomyopathy, hepatic form with recurrent hypoketotic hypoglycemia, and later-onset axonal sensory neuropathy with episodic myoglobinuria. METHODS: To identify the causative and characterize clinical features of a Korean family with motor and sensory neuropathies, whole exome study (WES), histopathologic study of distal sural nerve, and lower limb MRIs were performed. RESULTS: WES revealed that a compound heterozygous mutation in HADHB is the causative of the present patients. The patients exhibited an early-onset axonal sensorimotor neuropathy without episodic myoglobinuria, and showed typical clinical and electrophysiological features of CMT including predominant distal muscle weakness and atrophy. Histopathologic findings of sural nerve were compatible with an axonal CMT neuropathy. Furthermore, they didn't exhibit any other symptoms of the previously reported HADHB patients. CONCLUSIONS: These data implicate that mutation in HADHB gene can also cause early-onset axonal CMT instead of typical manifestations in mitochondrial trifunctional protein (MTP) deficiency. Therefore, this study is the first report of a new subtype of autosomal recessive axonal CMT by a compound heterozygous mutation in HADHB, and will expand the clinical and genetic spectrum of HADHB.

Immunoglobulin G4-associated inflammatory pseudotumor of urinary bladder: a case report.

A previously healthy 72-year old woman was admitted with a chief complaint of gross hematuria and fecaluria for 4 months. On initial computed tomographic examination, a lobulated shaped intravesical protruding mass with adhesion to the sigmoid colon was identified. Under a clinical diagnosis of bladder cancer with vesicosigmoid fistula vs sigmoid colon cancer with vesicosigmoid fistula, a frozen section evaluation of the bladder mass was performed to determine the origin of the tumor. Because the frozen section diagnosis of the bladder mass was an inflammatory origin, a partial cystectomy with segmental resection of the adherent sigmoid colon was elected. The microscopic examination of the partial resection of the urinary bladder revealed suburothelial inflammatory mass lesion, involving the entire wall of bladder with extension to the sigmoid colon, which was composed of spindle cells without significant atypia admixed with many lymphocytes, plasma cells, and some scattered eosinophils. Chronic inflammation around nerve bundles, sclerotic fibrosis, and prominent lymphoid follicles with plasma cells were the main features of the mass. No urothelial dysplasia or malignancy was seen. An average of 57 plasma cells per 1 high-power field was immunoreactive for immunoglobulin (Ig) G4 with IgG4/IgG ratio of more than 40%, a diagnostic feature of IgG4-associated inflammatory pseudotumor (IPT), arising in the bladder with the secondary involvement of the sigmoid colon. Recent studies reported many IPTs associated with IgG4 in other locations; however, to the best of our knowledge, IgG4-associated IPT in the urinary bladder has not been reported. We describe herein the first case of IgG4-associated IPT, lymphoplasmacytic type in the urinary bladder.

A complex phenotype of peripheral neuropathy, myopathy, hoarseness, and hearing loss is linked to an autosomal dominant mutation in MYH14.

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.

Two recessive intermediate Charcot-Marie-Tooth patients with GDAP1 mutations.

Various phenotypes have been reported in Charcot-Marie-Tooth (CMT) disease carrying mutations in the ganglioside-induced differentiation-associated protein 1 (GDAP1) gene. Here, we report two recessive intermediate Charcot-Marie-Tooth (RI-CMT) patients with GDAP1 missense mutations: a His256Arg homozygous mutation (c.767A>G + c.767A>G) and compound mutations of heterozygous Pro111His (c.332C>A) and Val219Gly (c.656T>G). The Pro111His and Val219Gly are unreported mutations, but the His256Arg was previously reported. In both patients, histopathological findings showed well-documented features of mixed demyelinating and axonal neuropathies, and nerve conduction velocities fall in the intermediate range. In addition, the patterns of fatty substitutions in leg magnetic resonance imaging (MRI) were different by the mutation sites within the same GDAP1 gene.

Myotonic dystrophy type I combined with X-linked dominant Charcot-Marie-Tooth neuropathy.

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.

Prognostic value of p16INK4a and p14ARF gene hypermethylation in human colon cancer.

The INK4a/ARF locus (9p21) encodes two unique and unrelated cell cycle regulators, p16INK4a and p14ARF. This study was performed to evaluate the methylation status of p16INK4a and p14ARF genes, as well as its association with p16 and p53 expression, microsatellite instability (MI) status, and various clinicopathologic parameters in sporadic colorectal cancer. Sixty-five cases of primary colorectal adenocarcinoma with a series of clinicopathological parameters were obtained. We performed methylation-specific PCR of p16INK4a and p14ARF genes in colorectal cancer paraffin blocks with its paired normal samples, as well as immunohistochemical stainings for p16 and p53, and MI analysis. Aberrant methylations of p16INK4a and p14ARF gene were present in 21 (32.3%) and 33 (50.8%) out of 65 cases, respectively. p16INK4a aberrant methylation was correlated with p16 negativity (P=0.021) and p53 overexpression (P=0.007). p16INK4a aberrant methylation was more frequently present in poorly differentiated adenocarcinomas (P=0.002). Aberrant methylation of p14ARF gene occurred more frequently in patients under 50 years of age and in left-sided colon cancers, and was not statistically significant. Compared with the group with simultaneous absence of methylation in both promoters, the group showing concomitant alterations in both p16INK4a and p14ARF genes (n=10) more frequently presented lymph node metastasis (P=0.020) and higher tumor grade (P=0.014). There was no correlation between p16INK4a and p14ARF gene hypermethylation or MI status. This study suggests that simultaneous hypermethylation of both p16INK4a and p14ARF genes is greater prognostic value in sporadic human colorectal cancer.

Recessive optic atrophy, sensorimotor neuropathy and cataract associated with novel compound heterozygous mutations in OPA1.

Mutations in the optic atrophy 1 gene (OPA1) are associated with autosomal dominant optic atrophy and 20% of patients demonstrate extra-ocular manifestations. In addition to these autosomal dominant cases, only a few syndromic cases have been reported thus far with compound heterozygous OPA1 mutations, suggestive of either recessive or semi­dominant patterns of inheritance. The majority of these patients were diagnosed with Behr syndrome, characterized by optic atrophy, ataxia and peripheral neuropathy. The present study describes a 10-year-old boy with Behr syndrome presenting with early­onset severe optic atrophy, sensorimotor neuropathy, ataxia and congenital cataracts. He had optic atrophy and was declared legally blind at six years old. Electrophysiological, radiological, and histopathological findings were compatible with axonal sensorimotor polyneuropathy. At birth, he presented with a congenital cataract, which has not been previously described in patients with OPA1 mutations. Whole exome sequencing indicated a pair of novel compound heterozygous mutations: p.L620fs*13 (c.1857­1858delinsT) and p.R905Q (c.G2714A). Neither mutation was observed in controls (n=300), and thus, they were predicted to be pathogenic by multiple in silico analyses. The mutation sites were highly conserved throughout different vertebrate species. The patients parents did not have any ophthalmic or neurologic symptoms and the results of electrophysiological studies were normal, suggestive of an autosomal recessive pattern of inheritance. The present study identified novel compound heterozygous OPA1 mutations in a patient with recessive optic atrophy, sensorimotor neuropathy and congenital cataracts, indicating an expansion of the clinical spectrum of pathologies associated with OPA1 mutations. Thus, OPA1 gene screening is advisable in the workup of patients with recessive optic atrophy, particularly with Behr syndrome and cataracts.

A family with axonal sensorimotor polyneuropathy with TUBB3 mutation.

Mutations in the ß­tubulin isotype III (TUBB3) gene result in TUBB3 syndrome that includes congenital fibrosis of the extraocular muscle type 3 (CFEOM3), intellectual impairments and/or an axonal sensorimotor neuropathy. In the present study, a TUBB3 D417N mutation was identified in a family with axonal sensorimotor polyneuropathy by whole exome sequencing. The proband exhibited gait disturbance at the age of 12 years and was wheelchair bound at 40 years. However, the proband's cousin exhibited gait disabilities at 45 years of age and was still able to walk when he was 60 years old. Ophthalmoplegia and intellectual impairment were not observed in either patient. A sural nerve biopsy identified an absence of large myelinated fibers without demyelinating degeneration. Based on these clinical features, the two patients exhibited an axonal peripheral neuropathy without CFEOM3. These results therefore suggested that certain TUBB3 mutations may predominantly be associated with axonal peripheral neuropathy. Furthermore, the results also suggested that TUBB3 mutations may be implicated in modulating the inter­ and intra­familial heterogeneity of clinical phenotypes.

Novel Compound Heterozygous Nonsense PRX Mutations in a Korean Dejerine-Sottas Neuropathy Family.

BACKGROUND: Mutations in the gene encoding periaxin (PRX) are known to cause autosomal recessive Dejerine-Sottas neuropathy (DSN) or Charcot-Marie-Tooth disease type 4F. However, there have been no reports describing Korean patients with these mutations. CASE REPORT: We examined a Korean DSN patient with an early-onset, slowly progressive, demyelinating neuropathy with prominent sensory involvement. Whole-exome sequencing and subsequent capillary sequencing revealed novel compound heterozygous nonsense mutations (p.R392X and p.R679X) in PRX. One mutation was transmitted from each of the patient's parents. No unaffected family member had both mutations, and the mutations were not found in healthy controls. CONCLUSIONS: We believe that these novel compound heterozygous nonsense mutations are the underlying cause of DSN. The clinical, electrophysiologic, and pathologic phenotypes in this family were similar to those described previously for patients with PRX mutations. We have identified the first PRX mutation in a Korean patient with DSN.

Bimodal upregulation of glial cell line-derived neurotrophic factor (GDNF) in the neonatal rat brain following ischemic/hypoxic injury.

In order to delineate the spatial and temporal patterns of glial cell line-derived neurotrophic factor (GDNF) expression following ischemic/hypoxic injury in immature and neonatal brain, GDNF protein levels and immunocytochemistry were studied in rats subjected to a modified Levine procedure. Significant upregulation of GDNF protein occurred in a bimodal fashion in the damaged left cerebral cortex and hippocampus, while the levels in the right cerebral hemisphere of both control and ischemic groups remained relatively unchanged. Immunocytochemical studies indicated that the early rise in GDNF levels was most likely to be related to enhanced neuronal release of GDNF. The second rise was probably related to progressive astrogliosis that occurred in response to injury. In contrast to the lack of GDNF expression among astrocytes in normal mature brains, reactive astrocytes in the neonate appear to possess a ready capacity to express GDNF. Spatial and temporal changes in the pattern of GDNF expression following injury, as determined in this study may provide insight into the functions of GDNF in vivo and into possible therapeutic approaches toward prevention of damage or rescue of neurons following brain injury.

Zonal difference and prognostic significance of foxp3 regulatory T cell infiltration in breast cancer.

PURPOSE: Forkhead box P3 (Foxp3) is known as the most specific marker for regulatory T lymphocytes, which play an important role in immune tolerance to disturb antitumor immunity. The present study aimed to investigate the prognostic significance of Foxp3 regulatory T lymphocyte (Foxp3 Treg) infiltration in breast cancer. METHODS: Immunohistochemical studies with Foxp3, CD4, and CD8 were performed on representative full tissue sections from 143 patients with invasive ductal carcinoma, not otherwise specified. Foxp3 Treg infiltration and the ratios between Foxp3 Treg and CD4 or CD8 T cells were separately analyzed for the tumor bed and tumor periphery to evaluate their association with different clinicopathological parameters and patients' outcome. RESULTS: The tumor periphery was considerably more densely infiltrated by Foxp3 Treg, CD4, and CD8 T cells than the tumor bed. Unfavorable clinicopathological parameters (a Ki-67 labeling index of ≥14%, a worse histologic grade, a worse nuclear grade, hormone receptor negativity, human epidermal growth factor receptor 2 positivity, and tumor recurrence) were associated with increased Foxp3 Treg infiltration and a high ratio between Foxp3 Treg and CD4/CD8 T cells. In the tumor periphery, as Foxp3 Treg infiltration and the Foxp3 Treg/CD8 ratio increased, patients' 5-year disease-free survival rate decreased. CONCLUSION: The infiltration densities of Foxp3 Treg, CD4, and CD8 T cells were markedly different between the tumor bed and periphery. Besides the absolute count of Foxp3 Treg, the ratio between Foxp3 Treg and effector T cells was a significant prognostic factor in breast cancer.

A novel MYH7 mutation with prominent paraspinal and proximal muscle involvement.

Laing distal myopathy (LDM) is caused by mutations in the MYH7 gene, and known to have muscle weakness of distal limbs and neck flexors. Through whole exome sequencing, we identified a novel p.Ala1439Pro MYH7 mutation in a Korean LDM family. This missense mutation is located in more N-terminal than any reported rod domain LDM mutations. In the early stage of disease, the present patients showed similar clinical patterns to the previously described patients of LDM. However, in the later stage, fatty replacement and atrophy of paraspinal or proximal leg muscles was more severely marked than lower leg muscles, and asymmetric atrophies were observed in trapezius, subscapularis and adductor magnus muscles. Distal myopathy like LDM showed marked and predominant fatty infiltrations in paraspinal or proximal leg muscles with marked asymmetry. These observations expand the clinical spectrum of LDM with the MYH7 mutation.