Exome sequencing identifies KIAA1377 and C5orf42 as susceptibility genes for monomelic amyotrophy

The Rogdi knockout mouse is a model for Kohlschütter-Tönz syndrome

Kohlschütter-Tönz syndrome (KTS) is a rare autosomal recessive disorder characterized by severe intellectual disability, early-onset epileptic seizures, and amelogenesis imperfecta. Here, we present a novel Rogdi mutant mouse deleting exons 6-11- a mutation found in KTS patients disabling ROGDI function. This Rogdi-/- mutant model recapitulates most KTS symptoms. Mutants displayed pentylenetetrazol-induced seizures, confirming epilepsy susceptibility. Spontaneous locomotion and circadian activity tests demonstrate Rogdi mutant hyperactivity mirroring patient spasticity. Object recognition impairment indicates memory deficits. Rogdi-/- mutant enamel was markedly less mature. Scanning electron microscopy confirmed its hypomineralized/hypomature crystallization, as well as its low mineral content. Transcriptomic RNA sequencing of postnatal day 5 lower incisors showed downregulated enamel matrix proteins Enam, Amelx, and Ambn. Enamel crystallization appears highly pH-dependent, cycling between an acidic and neutral pH during enamel maturation. Rogdi-/- teeth exhibit no signs of cyclic dental acidification. Additionally, expression changes in Wdr72, Slc9a3r2, and Atp6v0c were identified as potential contributors to these tooth acidification abnormalities. These proteins interact through the acidifying V-ATPase complex. Here, we present the Rogdi-/- mutant as a novel model to partially decipher KTS pathophysiology. Rogdi-/- mutant defects in acidification might explain the unusual combination of enamel and rare neurological disease symptoms.

Clinical and Genetic Analysis of A Father-Son Duo with Monomelic Amyotrophy: Case Report

Monomelic Amyotrophy (MMA) is a rare neurological disorder restricted to one upper limb, predominantly affecting young males with an unknown aetiopathogenesis. We report a familial case of father-son duo affected by MMA. Whole exome sequencing identified genetic variations in SLIT1, RYR3 and ARPP21 involved in axon guidance, calcium homeostasis and regulation of calmodulin signaling respectively. This is the first attempt to define genetic modifiers associated with MMA from India and advocates to extend genetic screening to a larger cohort. Deciphering the functional consequences of variations in these genes will be crucial for unravelling the pathogenesis of MMA.

Surgical Management of Hirayama Disease (Monomelic Amyotrophy): Systematic Review and Meta-Analysis of Patient-Level Data

BACKGROUND

Hirayama disease or juvenile-onset monomelic amyotrophy is a clinical syndrome that disproportionately affects young males. Standard of care revolves around conservative management, but some patients experience disease progression that may benefit from surgical intervention.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of previous reports of surgical treatment for Hirayama disease was performed. Studies were included if they provided individual patient-level data, described the clinical presentation and surgical intervention, and reported neurological improvement at last follow-up. Comparison between those who improved and those with stable symptoms at last follow-up was performed. Decision-tree analysis was used to identify the best predictors of neurological improvement by last follow-up.

RESULTS

Of 624 unique articles, 30 were included in the qualitative review and 23 in the meta-analysis. Among the 70 patients in the meta-analysis, mean age was 21.2 ± 6.3 years, 91% were male, and mean symptom duration at presentation was 43.3 ± 61.8 months. Fifty-nine patients (84.3%) had improvement in their neurological symptoms by last follow-up. Univariable analysis showed the only significant predictor of improvement in neurological symptoms by last follow-up was the use of stabilization-alone versus decompression with or without stabilization. Baseline clinical symptoms nor radiographic features predicted outcome. Decision-tree analysis showed surgical strategy (stabilization-alone vs. decompression ± stabilization), age (<20 vs. ≥20), and surgical approach (anterior-only vs. posterior-only or anterior-posterior) predicted a higher likelihood of neurological improvement by last follow-up.

CONCLUSIONS

Nearly 85% of patients experienced improvement in neurological symptoms. Improvement was best for those who underwent stabilization-alone, and decision-tree analysis suggested that the likelihood of improvement was also superior for patients under 20 years of age and those treated with an anterior versus posterior or staged approach.

Update on the Pathogenesis, Clinical Diagnosis, and Treatment of Hirayama Disease

Hirayama disease (HD) is characterized by the juvenile onset of unilateral or asymmetric weakness and amyotrophy of the hand and ulnar forearm and is most common in males in Asia. A perception of compliance with previous standards of diagnosis and treatment appears to be challenged, so the review is to update on HD. First, based on existing theory, the factors related to HD includes, (1) cervical cord compression during cervical flexion, (2) immunological factors, and (3) other musculoskeletal dynamic factors. Then, we review the clinical manifestations: typically, (1) distal weakness and wasting in one or both upper extremities, (2) insidious onset and initial progression for 3-5 years, (3) coarse tremors in the fingers, (4) cold paralysis, and (5) absence of objective sensory loss; and atypically, (1) positive pyramidal signs, (2) atrophy of the muscles of the proximal upper extremity, (3) long progression, and (4) sensory deficits. Next, updated manifestations of imaging are reviewed, (1) asymmetric spinal cord flattening, and localized lower cervical spinal cord atrophy, (2) loss of attachment between the posterior dural sac and the subjacent lamina, (3) forward displacement of the posterior wall of the cervical dural sac, (4) intramedullary high signal intensity in the anterior horn cells on T2-weighted imaging, and (5) straight alignment or kyphosis of cervical spine. Thus, the main manifestations of eletrophysiological examinations in HD include segmental neurogenic damages of anterior horn cells or anterior roots of the spinal nerve located in the lower cervical spinal cord, without disorder of the sensory nerves. In addition, definite HD needs three-dimensional diagnostic framework above, while probable HD needs to exclude other diseases via "clinical manifestations" and "electrophysiological examinations". Finally, the main purpose of treatment is to avoid neck flexion. Cervical collar is the first-line treatment for HD, while several surgical methods are available and have achieved satisfactory results. This review aimed to improve the awareness of HD in clinicians to enable early diagnosis and treatment, which will enable patients to achieve a better prognosis.

Monomelic Amyotrophy (Hirayama Disease): A Rare Case Report and Literature Review

Hirayama disease is a rare neurological entity that is characterized by initial progressive muscular wasting and weakness of the distal upper limb in young men, followed by a spontaneous arrest within several years. The disease is believed to be a result of forward displacement of the cervical dural sac and spinal cord induced by neck flexion. It is commonly seen in Asia and rarely encountered in the Middle East countries. We report a rare case of a 20-year-old Kuwaiti patient presenting with a 10-month duration of gradual left upper limb weakness and wasting. We describe his electrophysiological and radiological findings that confirmed the diagnosis, and conducted a literature review. Hirayama disease is rarely encountered in clinical settings and should be suspected in male patients presenting with unilateral or asymmetrical bilateral lower motor weakness of hands and forearms. It is a benign entity, and cervical collar is usually the only treatment needed in most cases.

Intrafamilial phenotypic variations in familial cases of cervical flexion induced myelopathy/Hirayama disease

Hirayama disease is generally considered to be a sporadic disorder, except for a few reports of familial occurrence. In this study, we describe eight patients from four families with cervical flexion induced myelopathy (CFIM)/Hirayama disease (HD) and intra-familial phenotypic variations. All underwent clinical and electrophysiological evaluation, while seven of them had contrast MR imaging of cervical spine in flexion. There was significant intra-familial variability: distal bimelic form in four patients, classical monomelic form in three and proximo-distal form in one. Irrespective of the clinical phenotype, MRI showed characteristic dynamic changes of posterior dural detachment with prominent epidural enhancement extending variably from C3 vertebral level to dorsal spine in six patients. One patient with 28 years of illness, had only lower cervical cord atrophy without dynamic changes while another patient demonstrated forward dural displacement with epidural enhancement even after 38 years of disease duration.

Risk Factors for Surgical Results of Hirayama Disease: A Retrospective Analysis of a Large Cohort

OBJECTIVE

To explore risk factors affecting surgical results of Hirayama disease.

METHODS

A retrospective analysis of 210 patients was performed to identify risk factors affecting surgical results of Hirayama disease by using univariate and multivariate analyses. A receiver operating characteristic curve and area under the curve were applied to evaluate the significant results of the multivariate analysis and the optimal reference value.

RESULTS

The mean follow-up period was 27.3 months (range, 14-45 months), and 194 patients with clinical and radiographic data completed the final follow-up. Multivariate analysis identified age of patients (cutoff value 22.5 years), duration of the disease (cutoff value 33 months), physiologic reflex, and pathologic reflex as independent risk factors for surgical results of Hirayama disease. The receiver operating characteristic curve analysis and area under the curve showed that good reference value was obtained for the risk factors.

CONCLUSIONS

Age of patient, duration of the disease, physiologic reflex, and pathologic reflex are the main risk factors affecting surgical results of Hirayama disease. Receiver operating characteristic analysis shows that good reference value was obtained for the risk factors.

Cortical function and corticomotoneuronal adaptation in monomelic amyotrophy

OBJECTIVE

To evaluate corticomotoneuronal integrity in monomelic amyotrophy using threshold tracking transcranial magnetic stimulation (TT-TMS).

METHODS

Cortical excitability studies were prospectively performed in 8 monomelic amyotrophy patients and compared to 21 early-onset amyotrophic lateral sclerosis (ALS) patients and 40 healthy controls. Motor evoked potentials responses were recorded over abductor pollicis brevis.

RESULTS

Maximal motor evoked potential (MEP/CMAP ratio) was significantly increased in monomelic amyotrophy compared with controls (monomelic amyotrophy 51.2±12.4%; control 22.7±2.1%, p=0.04). Averaged short-interval intracortical inhibition (SICI, ISI 1-7ms) in monomelic amyotrophy patients was similar to controls (monomelic amyotrophy 9.6±2.1%; control 10.0±0.9%, p=0.98). However, it was significantly reduced in early-onset ALS in comparison with monomelic amyotrophy patients (monomelic amyotrophy 9.6±2.1%; ALS 2.3±1.7%, p<0.001). Averaged SICI is a good parameter (area under the curve 0.79, p=0.02) to discriminate between monomelic amyotrophy and early-onset ALS patients.

CONCLUSIONS

TT-TMS technique has identified normal cortical function in monomelic amyotrophy, a feature that distinguishes it from early-onset ALS. The greater corticomotoneuronal projections to spinal motoneurons may represent central nervous system adaptive change in monomelic amyotrophy.

SIGNIFICANCE

Corticomotoneuronal dysfunction does not drive the lower motor neurone loss presented in monomelic amyotrophy.

KIAA1377 is associated with lymph node metastasis in esophageal squamous cell carcinoma

KIAA1377, of which there are few studies regarding cell biology and neurological diseases, has been found to be significantly amplified in esophageal squamous cell carcinoma (ESCC) with lymph node metastasis compared with ESCC without lymph node metastasis. This suggests that KIAA1377 may play a role in the lymph node metastasis of ESCC. There has, to the best of our knowledge, been no study performed to investigate the role of KIAA1377 in ESCC. In the present study, the expression of KIAA1377 was detected by immunohistochemistry, and its expression was statistically analyzed with clinicopathological parameters, using commercially obtained tissue arrays consisting of 86 cases of ESCC and 79 paired controls. KIAA1377 was knocked down ex vivo using transient transfection with specific small hairpin RNA (shRNA) vectors into ESCC TE-1 and EC9706 cell lines whose endogenous KIAA1377 level was highest. The variation of proliferation, migration and invasion were evaluated using methyl thiazolyl tetrazolium, wound healing and Transwell assay, respectively. It was found in vivo that KIAA1377 expression was significantly associated with lymph node metastasis and differentiation, and ex vivo that knockdown of KIAA1377 cannot significantly affect proliferation and mobility in the ESCC cell line TE-1. Overall, this is the first study suggesting that KIAA1377 may play a role in the lymph node micrometastasis of ESCC.

Hirayama Disease with Proximal Involvement

Hirayama disease is a slowly progressing benign motor neuron disease that affects the distal upper limb. A 29-year-old man visited the hospital with a 1-year history of weakened left proximal upper limb. He was diagnosed with Hirayama disease 9 years ago, while there was no further progression of the muscle weakness afterward. Atrophy and weakness was detected in proximal upper limb muscles. Magnetic resonance imaging and somatosensory evoked potentials were normal. Needle electromyography showed abnormal findings in proximal upper limb muscles. Our patient had Hirayama disease involving the proximal portion through secondary progression. Clinical manifestation and accurate electromyography may be useful for diagnosis. Rare cases with progression patterns as described here are helpful and have clinical meaning for clinicians.

Juvenile muscular atrophy of the distal upper extremities associated with x-linked periventricular heterotopia with features of Ehlers-Danlos syndrome

INTRODUCTION

Juvenile muscular atrophy of the distal upper extremities (JMADUE) is a rare, sporadic disorder that affects adolescent males and is characterized by progressive but self-limited weakness of the distal upper extremities. The etiology is unknown, but cervical hyperflexion has been hypothesized.

METHODS

We report a case of an adolescent male who presented with typical JMADUE but also had joint hypermobility and multiple congenital anomalies, including periventricular heterotopias, suggesting a multisystem syndrome.

RESULTS

Subsequent diagnostic testing confirmed a diagnosis of JMADUE, and sequencing of the filamin-A gene showed a novel, pathogenic mutation that confirmed an additional diagnosis of X-linked periventricular heterotopias with features of Ehlers-Danlos syndrome (XLPH-EDS).

CONCLUSIONS

The concurrent diagnosis of these 2 rare conditions suggests a pathogenic connection. It is likely that the joint hypermobility from XLPH-EDS predisposed this patient to developing JMADUE. This supports the cervical hyperflexion theory of pathogenesis. This case also expands the phenotype associated with FLNA mutations. Muscle Nerve 54: 794-797, 2016.

Clinical profile of Monomelic Amyotrophy (MMA) and role of persistent viral infection

OBJECTIVES

The objective of our study was to describe the clinical characteristics, electrophysiology, MRI features and conduct viral assays in patients with Monomelic Amyotrophy (MMA) and follow them up over one year.

METHODS

Consecutive patients with MMA who attended the Neurology services from April 2013 to March 2014 were included. Age and sex matched controls were taken for the purpose of viral assay analysis. The clinical evaluation was repeated at six months and one year.

RESULTS

109 cases and 109 controls were included in the study. The patients were predominantly males (98.2%; n=107/109) and had involvement of upper limbs (83.5%; n=91/109). 26 (23.8%) patients with clinically unilateral involvement had bilateral neurogenic changes in the electromyography. Serological assays of Japanese E, West Nile Virus, and Poliovirus 1, 2 and 3, HIV 1 and 2 were negative in all the cases and controls.

CONCLUSIONS

Patients with MMA are predominantly young males with upper limb wasting and weakness. MRI of the cervical cord is normal in most of the patients (67.9%). The present study did not find any evidence of the association of viral infection in MMA.

Hirayama Disease: Escaping From the Quotidian Imaging

Hirayama disease is a rare type of neurological disease commonly manifesting as brachial monomelic amyotrophy in young males of Asian origin, easily understood as juvenile non-progressive cervical amyotrophy. The first case was reported by Hirayama in 1959. The pathogenesis is attributed towards chronic compression of cervical spinal cord during flexion movements of neck in cases where there is detachment of posterior dura mater. This chronic event, invariably leads to features of cord atrophy along with other MRI features. We report a case of 21-year-old male who presented with atrophy of distal muscles of his right hand and was sent for MRI of cervical spine which revealed prominent posterior epidural venous plexus without significant cord atrophy. Clinico-radiologic profile of the patient leads toward the diagnosis of Hirayama disease which was considered as borderline because of asymmetrical cord atrophy which is a not a routine imaging feature of the entity.

Cep126 is required for pericentriolar satellite localisation to the centrosome and for primary cilium formation

Background Information

The centrosome is the primary microtubule-organising centre of animal cells and it has crucial roles in several fundamental cellular functions, including cell division, cell polarity, and intracellular transport. The mechanisms responsible for this are not completely understood.

Results

The poorly characterised protein CEP126 localises to the centrosome, pericentriolar satellites and the base of the primary cilium. Suppression of CEP126 expression results in dispersion of the pericentriolar satellites and disruption of the radial organisation of the microtubules, and induces disorganisation of the mitotic spindle. Moreover, CEP126 depletion or the transfection of a CEP126 truncation mutant in hTERT-RPE-1 and IMCD3 cells impairs the formation of the primary cilium.

Conclusions

We propose that CEP126 is a regulator of microtubule organisation at the centrosome that acts through modulation of the transport of pericentriolar satellites, and consequently, of the organisation of cell structure.

Next generation sequencing for neurological diseases: new hope or new hype?

Over the past year huge advances have been made in our ability to determine the genetic aetiology of many neurological diseases through the utilisation of next generation sequencing platforms. This technology is, on a daily basis, providing new breakthroughs in neurological disease. The aim of this article is to clearly describe the technological platforms, methods of data analysis, established breakthroughs, and potential future clinical and research applications of this innovative and exciting technique which has relevance to all those working within clinical neuroscience.