In Vivo Evaluation of White Matter Abnormalities in Children with Duchenne Muscular Dystrophy Using DTI

BACKGROUND AND PURPOSE

Duchenne muscular dystrophy is an X-linked disorder characterized by progressive muscle weakness and prominent nonmotor manifestations, such as a low intelligence quotient and neuropsychiatric disturbance. We investigated WM integrity in patients with Duchenne muscular dystrophy using DTI.

MATERIALS AND METHODS

Fractional anisotropy and mean, axial, and radial diffusivity (DTI measures) were used to assess WM microstructural integrity along with neuropsychological evaluation in patients with Duchenne muscular dystrophy (n = 60) and controls (n = 40). Exon deletions in the DMD gene were confirmed using multiplex ligation-dependent probe amplification. Patients were classified into proximal (DMD Dp140+) and distal (DMD Dp140-) subgroups based on the location of the exon deletion and expression of short dystrophin Dp140 isoform. WM integrity was examined using whole-brain Tract-Based Spatial Statistics and atlas-based analysis of DTI data. The Pearson correlation was performed to investigate the possible relationship between neuropsychological scores and DTI metrics.

RESULTS

The mean ages of Duchenne muscular dystrophy and control participants were 8.0 ± 1.2 years and 8.2 ± 1.4 years, respectively. The mean age at disease onset was 4.1 ± 1.8 years, and mean illness duration was 40.8 ± 25.2 months. Significant differences in neuropsychological scores were observed between the proximal and distal gene-deletion subgroups, with more severe impairment in the distal-deletion subgroup (P < .05). Localized fractional anisotropy changes were seen in the corpus callosum, parietal WM, and fornices in the patient subgroup with Dp140+, while widespread changes were noted in the Dp140- subgroup. The Dp140+ subgroup showed increased axial diffusivity in multiple WM regions relative to the Dp140- subgroup. No significant correlation was observed between clinical and neuropsychological scores and diffusion metrics.

CONCLUSIONS

Widespread WM differences are evident in patients with Duchenne muscular dystrophy relative to healthy controls. Distal mutations in particular are associated with extensive WM abnormalities and poor neuropsychological profiles.

Evidence for Mycobacterium leprae Drug Resistance in a Large Cohort of Leprous Neuropathy Patients from India

Resistance to anti-leprosy drugs is on the rise. Several studies have documented resistance to rifampicin, dapsone, and ofloxacin in patients with leprosy. We looked for point mutations within the folP1, rpoB, and gyrA gene regions of the Mycobacterium leprae genome predominantly in the neural form of leprosy. DNA samples from 77 nerve tissue samples were polymerase chain reaction (PCR)-amplified for M leprae DNA and sequenced for drug resistance-determining regions of genes rpoB, folP1, and gyrA. The mean age at presentation and onset was 38.2 ± 13.4 (range 14-71) years and 34.9 ± 12.6 years (range 10-63) years, respectively. The majority had borderline tuberculoid leprosy (53 [68.8%]). Mutations associated with resistance were identified in 6/77 (7.8%) specimens. Mutations seen were those associated with resistance to rifampicin, ofloxacin, and dapsone. All the six patients were drug-naive. The clinical and pathological manifestations in this group did not differ from the drug-sensitive group. This study highlights the occurrence of resistance to the standard multidrug therapy and ofloxacin in leprosy. Among the entire cohort, 1/77 (1.3%) showed resistance to rifampicin, 2/77 (2.6%) to dapsone, and 5/77 (6.4%) to ofloxacin. Six new patients showing infection by mutant strains indicated the emergence of primary resistance. Resistance to ofloxacin could be due to frequent use of quinolones for many bacterial infections. The results of the study indicate the need for development of a robust and strict surveillance system for detecting drug resistance in leprosy in India.

Appropriately Selected Nerve in Suspected Leprous Neuropathy Yields High Positive Results for Mycobacterium leprae DNA by Polymerase Chain Reaction Method

Identification of Mycobacterium leprae DNA by polymerase chain reaction (PCR) is a reliable and an affordable method to confirm leprosy. DNA from 87 nerve samples (61 from paraffin blocks and 26 fresh samples) was extracted. Mycobacterium leprae DNA was amplified by PCR from 80/87 (92%) specimens. Patients were seen over a period of 11 years (2007-2019), and leprosy was diagnosed based on clinical and characteristic histopathology findings. The clinical diagnostic possibilities were as follows: leprous neuropathy in 73/80 (91.3%), mononeuritis multiplex of unknown etiology in four (5.0%), vasculitic neuropathy in two (2.5%), and distal symmetric sensory motor neuropathy in one (1.3%). The biopsied nerves were as follows: superficial radial = 34 (42.6%), dorsal cutaneous branch of ulnar = 19 (23.8%), sural = 18 (22.5%), and superficial peroneal = 9 (11.3%), and corresponding neurological deficits were recorded in 77 (96.3%) cases. The histopathological diagnoses in total group were as follows: (borderline tuberculoid (BT) = 52, tuberculoid (TT) = 8, borderline lepromatous (BL) = 8, borderline borderline (BB) = 3, nonspecific inflammation = 3, healed/fibrosed = 4, and axonopathy = 2). Acid fast bacilli (AFB) was demonstrated in 11 (13.7%) samples. For comparison, 31 clinically and histopathologically defined non-leprous disease control nerves (inherited neuropathy = 20, vasculitis = 8, and nutritional neuropathy = 3) subjected to PCR were negative for M. leprae DNA. In most instances, there are multiple thickened peripheral nerves in suspected cases of leprosy, but neurological deficits pertaining to the thickened nerve are not as widespread. The current findings emphasize the importance of selecting the most appropriate nerve for biopsy to obtain a positive PCR result. We infer that clinical, histopathological, and PCR tests complement each other to help achieve a definitive diagnosis of leprosy particularly in pure neuritic leprosy and in leprous neuropathy with negative skin smears/biopsy.

C9orf72 hexanucleotide repeat expansion in Indian patients with ALS: a common founder and its geographical predilection

Hexanucleotide repeat expansion in C9orf72 is defined as a major causative factor for familial amyotrophic lateral sclerosis (ALS). The mutation frequency varies dramatically among populations of different ethnicity; however, in most cases, C9orf72 mutant has been described on a common founder haplotype. We assessed its frequency in a study cohort involving 593 clinically and electrophysiologically defined ALS cases. We also investigated the presence of reported Finnish haplotype among the mutation carriers. The identified common haplotype region was further screened in 192 (carrying 2-6 G4C2 repeats) and 96 (≥7 repeats) control chromosomes. The G4C2 expansion was observed in 3.2% (19/593) of total cases where 9/19 (47.4%) positive cases belonged to the eastern region of India. Haplotype analysis revealed 11 G4C2-Ex carriers shared the common haplotype (haplo-A) background spanning a region of ∼90 kbp (rs895021-rs11789520) including rs3849942 (a well-known global at-risk loci with T allele for G4C2 expansion). The other 3 G4C2-Ex cases had a different haplotype (haplo-B) with core difference from haplo-A at G4C2-Ex flanking 31 kbp region between rs3849942 and rs11789520 SNPs (allele 'C' of rs3849942 which is a nonrisk allele). Out of other five G4C2-cases, four carried the risk allele T of rs3849942 while one harbored the non-risk allele. This study establishes the prevalence of C9orf72 expansion in Indian ALS cases providing further evidence for geographical predilection. The global core risk haplotype predominated C9orf72 expansion-positive ALS cases, yet the existence of a different haplotype suggests a second lineage (haplo B), which may have been derived from the Finnish core haplotype or may imply a unique haplotype among Asians. The association of risk haplotype with normal intermediate C9orf72 alleles reinforced its role in conferring instability to the C9orf72-G4C2 region. We thus present an effective support to interpret future burden of ALS cases in India.

Brain and Spinal Cord Lesions in Leprosy: A Magnetic Resonance Imaging-Based Study

Neurotropism and infiltration by Mycobacterium leprae of peripheral nerves causing neuropathy are well established, but reports of central nervous system (CNS) damage are exceptional. We report CNS magnetic resonance imaging (MRI) abnormalities of the brain and spinal cord as well as lesions in nerve roots and plexus in leprosy patients. Eight patients aged between 17 and 41 years underwent detailed clinical, histopathological, and MRI evaluation. All had prominent sensory-motor deficits with hypopigmented and hypo/anesthetic skin patches and thickened peripheral nerves. All demonstrated M. Leprae DNA in affected peripheral nerve tissue. All received multidrug therapy (MDT). Two patients had brainstem lesions with enhancing facial nuclei and nerves, and one patient had a lesion in the nucleus ambiguus. Two patients had enhancing spinal cord lesions. Follow-up MRI performed in four cases showed resolution of brainstem and cord lesions after starting on MDT. Thickened brachial and lumbosacral plexus nerves were observed in six and two patients, respectively, which partially resolved on follow-up MRI in the two cases who had reimaging. The site and side of the MRI lesions corresponded with the location and side of neurological deficits. This precise clinico-radiological correlation of proximal lesions could be explained by an immune reaction in the gray matter corresponding to the involved peripheral nerves, retrograde axonal and gray matter changes, or infection of the CNS and plexus by lepra bacilli. Further study of the CNS in patients with leprous neuropathy is needed to establish the exact nature of these CNS MRI findings.

Hirayama disease/cervical flexion-induced myelopathy progressing to spastic paraparesis: A report on three cases with literature review

Hirayama disease (HD)/cervical flexion-induced myelopathy (CFIM) is a lower motor neuron disease conventionally affecting a single upper extremity. We describe three men progressing after a long stable period to develop severe spastic paraparesis and bladder disturbances as a protracted implication of HD. The age at onset was 20, 24, and 15 years, while the age at presentation was 27, 41, and 57 years, respectively. The second phase of disease progression occurred after 4, 13, and 28 years of stationary period. All had CFIM with characteristic magnetic resonance imaging features as observed during progressive stages. The anterior dural shift extended variably from C4 to D4 levels with a median value of 5 mm and was maximum at C6 to C7 levels, pushing the cord anteriorly causing compression. This study emphasizes the need to recognize this unusual subgroup of HD and mandates long-term follow-up with timely intervention in arresting the progression/improving the deficits.

Family Caregivers' Experiences with Dying and Bereavement of Individuals with Motor Neuron Disease in India

Motor neuron disease (MND) is a progressive neurodegenerative disease. Ideal management plan in MND includes palliative care initiated from the time of diagnosis. At present, most of the neurodegenerative conditions are cared for at home. Neuropalliative care is an emerging concept in India and social workers are integral team members in this process. The primary aims of the study were to explore (a) the caregivers' experiences of the end-of-life stage, and (b) the sources of support for individuals and their caregivers with MND at the end-of-life stage. In-depth interviews were conducted with seven bereaved caregivers of individuals with MND from a national tertiary referral care center for neuropsychiatry in South India. Interviews were conducted either in person or by telephone. Thematic analysis was done using the constant comparative method. Major themes derived from the interviews were: (1) Transition from person to patient, (2) support, (3) death, and (4) impact on the caregivers. Mapping of themes identified "Support received during advanced stages" as the central theme influencing all other themes. The need for a care manager seems evident and is a role that can be effectively fulfilled by the care teams' social workers.

MACF1 links Rapsyn to microtubule- and actin-binding proteins to maintain neuromuscular synapses

Oury et al. show that the scaffolding protein MACF1 links Rapsyn, which binds acetylcholine receptors, to the microtubule- and actin-network at neuromuscular synapses. MACF1 thereby plays a role in synaptic maturation in mice, and mutations of MACF1 are associated with congenital myasthenia in humans.

Complex mechanisms are required to form neuromuscular synapses, direct their subsequent maturation, and maintain the synapse throughout life. Transcriptional and post-translational pathways play important roles in synaptic differentiation and direct the accumulation of the neurotransmitter receptors, acetylcholine receptors (AChRs), to the postsynaptic membrane, ensuring for reliable synaptic transmission. Rapsyn, an intracellular peripheral membrane protein that binds AChRs, is essential for synaptic differentiation, but how Rapsyn acts is poorly understood. We screened for proteins that coisolate with AChRs in a Rapsyn-dependent manner and show that microtubule actin cross linking factor 1 (MACF1), a scaffolding protein with binding sites for microtubules (MT) and actin, is concentrated at neuromuscular synapses, where it binds Rapsyn and serves as a synaptic organizer for MT-associated proteins, EB1 and MAP1b, and the actin-associated protein, Vinculin. MACF1 plays an important role in maintaining synaptic differentiation and efficient synaptic transmission in mice, and variants in MACF1 are associated with congenital myasthenia in humans.

Ventral longitudinal intraspinal fluid collection: Rare presentation as brachial amyotrophy and intracranial hypotension

CONTEXT

Ventral longitudinal intraspinal fluid collection (VLISFC) presenting as hand amyotrophy has been described only in a few cases and there are no reports on associated intracranial CSF hypovolemia (ICH). We describe the clinical and imaging findings of a case with combined brachial amyotrophy and ICH secondary to VLISFC.

FINDINGS

A 31 year old man presented with severe positional neck discomfort, radiating pain, progressive asymmetrical wasting and weakness of distal upper limbs. Contrast Magnetic Resonance Imaging (MRI) of the spine demonstrated a ventral extradural intraspinal fluid collection extending from upper border of C6 to lower border of T3 vertebra with pockets of dorsal collection. Three-dimensional constructive interference in steady state (CISS 3D) used in spinal imaging for identification of CSF leak corroborated with the extent seen on T2 sagittal sections; however, the site of the leak was not identified. After a year he developed disturbing postural headache which was relieved in recumbent position. Follow up MRI of brain was normal while spine demonstrated significant cervical cord atrophy and bilateral cord white matter hyperintensities. Conclusion / Clinical Relevance: We report this unusual case where local compression by VLISFC located at the cervical and upper thoracic level not only caused distal bi-brachial amyotrophy mimicking Hirayama disease but also led to secondary intracranial hypotension. An early identification and intervention could possibly have prevented the onset of ICH.

Caregiver burden and quality of life of patients with amyotrophic lateral sclerosis in India

AIM

Amyotrophic lateral sclerosis (ALS) or motor neuron disease (MND) is a progressive degenerative disorder that can have significant debilitating impact. Few studies have explored living with ALS in the developing countries. The study aims to understand the relationship between functionality, quality of life, and caregiver burden in ALS in the sociocultural scenario in India.

METHODS

A cross-sectional descriptive study was performed among 30 persons with ALS and their caregivers (men = 19; women = 11) receiving treatment from a national quaternary referral care center for Neurological disorders in Southern India. All patients were diagnosed as Definite ALS according to El Escorial Criteria. The mean age at onset of illness was 51.6 years and mean duration of illness at presenting to hospital was 11 months. The caregivers were spouses, offspring, or siblings. Variables were assessed with ALS Functional Rating Scale Revised (ALSFRS- R), ALS Specific Quality of Life Scale (ALSSQOL-R) with the patients and Zarit Burden Interview (ZBI) with the caregiver.

RESULTS

Functionality and quality of life negatively correlated with caregiver burden. Caregiver burden was negatively associated with "negative emotional state" and "interaction of the patient with family and environment", sub domains in ALSQOL scale. No significant association was noted between caregiver burden and intimacy, religiosity as well as physical symptoms domains of quality of life.

CONCLUSION

ALS patients and caregivers would benefit from structured care plan that is sensitive to the impact of the illness on the specific domains of quality of life as well as the deterioration in the neurological functioning.

Recessive variants of MuSK are associated with late onset CMS and predominant limb girdle weakness

Congenital myasthenic syndrome (CMS) is a heterogeneous disorder that causes fatigable muscle weakness. CMS has been associated with variants in the MuSK gene and, to date, 16 patients have been reported. MuSK-CMS patients present a different phenotypic pattern of limb girdle weakness. Here, we describe four additional patients and discuss the phenotypic and clinical relationship with those previously reported. Two novel damaging missense variants are described: c.1742T > A; p.I581N found in homozygosis, and c.1634T > C; p.L545P found in compound heterozygosis with p.R166*. The reported patients had predominant limb girdle weakness with symptom onset at 12, 17, 18, and 30 years of age, and the majority exhibited a good clinical response to Salbutamol therapy, but not to esterase inhibitors. Meta-analysis including previously reported variants revealed an increased likelihood of a severe, respiratory phenotype with null alleles. Missense variants exclusively affecting the kinase domain, but not the catalytic site, are associated with late onset. These data refine the phenotype associated with MuSK-related CMS.

Case Report: Neurobrucellosis with Plastered Spinal Arachnoiditis: A Magnetic Resonance Imaging-Based Report

Diffuse spinal arachnoiditis in neurobrucellosis is a rare manifestation. We report a boy aged 17, presenting with hearing impairment and recurrent vomiting for 18 months, weight loss for 12 months, dysphagia, dysarthria, hypophonia for 6 months, and gait unsteadiness for 5 months. He had bilateral 5th (motor) to 12th cranial nerve palsy, wasting and weakness of limbs, fasciculations, absent tendon reflexes, and positive Babinski's sign. Cerebrospinal fluid (CSF) showed raised protein and pleocytosis. Magnetic resonance imaging (MRI) showed extensive enhancing exudates in cisterns and post-contrast enhancement of bilateral 5th, 6th, 7th, and 8th nerves. Spine showed clumping with contrast enhancement of the cauda equina roots and encasement of the cord with exudates. Serum and CSF were positive for anti-Brucella antibodies. He showed significant improvement with antibiotics. At 4 months follow-up, MRI demonstrated near complete resolution of cranial and spinal arachnoiditis. It is important to recognize such rare atypical presentations of neurobrucellosis.

Mutations causing congenital myasthenia reveal principal coupling pathway in the acetylcholine receptor ε-subunit

We identify 2 homozygous mutations in the ε-subunit of the muscle acetylcholine receptor (AChR) in 3 patients with severe congenital myasthenia: εR218W in the pre-M1 region in 2 patients and εE184K in the β8-β9 linker in 1 patient. Arg218 is conserved in all eukaryotic members of the Cys-loop receptor superfamily, while Glu184 is conserved in the α-, δ-, and ε-subunits of AChRs from all species. εR218W reduces channel gating efficiency 338-fold and AChR expression on the cell surface 5-fold, whereas εE184K reduces channel gating efficiency 11-fold but does not alter AChR cell surface expression. Determinations of the effective channel gating rate constants, combined with mutant cycle analyses, demonstrate strong energetic coupling between εR218 and εE184, and between εR218 and εE45 from the β1-β2 linker, as also observed for equivalent residues in the principal coupling pathway of the α-subunit. Thus, efficient and rapid gating of the AChR channel is achieved not only by coupling between conserved residues within the principal coupling pathway of the α-subunit, but also between corresponding residues in the ε-subunit.

Demonstration of autonomic dysfunction in traumatic brachial plexus injury using quantitative sudomotor axon reflex test: Preliminary results

OBJECTIVE

To objectively document autonomic dysfunction in the affected arm with traumatic brachial plexus injury (TBPI) using quantitative sudomotor axon reflex test (QSART).

MATERIALS AND METHODS

Patients with TBPI presenting to the neurosurgical outpatient department from August 2013 to November 2014 were included in the study. The QSART was administered to each patient with prior informed consent detailing the procedure. A total of 20 patients with TBPI were included in the study. The age, sex, mode of injury, date of injury, side of injury, and type of injury (pan brachial plexus vs preserved distal function) were recorded. The presence of any pain was also recorded. The injuries were also grouped as preganglionic and postganglionic injuries based on clinical, electroneuromyography (ENMG) and magnetic resonance imaging (MRI) findings. The results of the test for the affected and normal limb were recorded and analyzed with appropriate statistical tests to determine any significant differences.

RESULTS

The study included 20 patients, with their age ranging from 15 to 50 years. Out of the 20 patients, one was female and the rest 19 were males. Seven (35%) of the injuries were complete (pan brachial plexus) and 13 (65%) were incomplete (preserved distal function). All patients had preganglionic TBPI. There was no evidence of any statistically significant difference between the affected and normal arm for total sweat volume (P = 0.20) and latency period (P = 0.42). However, the average mean values for the same were lower in the affected arm as compared to the normal. The baseline sweat output (P = 0.010), however, was significantly lower in the affected arm as compared to the normal arm.

CONCLUSION

QSART has demonstrated reduced baseline sweat output in the affected arm in patients with TBPI. This indicates the presence of autonomic dysfunction in the injured arm.

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.