Seena Vengalil

Reverse split hand syndrome: Dissociated intrinsic hand muscle atrophy pattern in Hirayama disease/brachial monomelic amyotrophy

Abstract Preferential involvement of C7, C8, T1 level anterior horn cells is a typical feature in Hirayama disease/brachial monomelic amyotrophy (BMMA). There are no clinico-electrophysiological studies to substantiate the peculiar pattern of muscle involvement. Thirty subjects, 10 in each group of BMMA, amyotrophic lateral sclerosis (ALS) and age-matched normal healthy subjects underwent detailed clinical and electrophysiological testing. Results showed that the mean age at evaluation for BMMA and ALS patients was 25.8 ± 3.8 and 51.8 ± 9.5 years, respectively; illness duration was 8.1 ± 5.7 years and 11.14 ± 2.85 months, respectively. Clinically, all BMMA patients had reverse of split hand (RSH) syndrome [abductor digiti minimi (ADM) affected more than abductor pollicis brevis (APB)], while 7/10 ALS patients had classical split hand syndrome (APB affected more than ADM). In BMMA, the compound muscle action potential (CMAP) of APB was preserved but reduced/absent in ADM compared to the ALS group which demonstrated reverse findings. APB/ADM ratio was >0.8 in the BMMA group (>1.4 in 80%), around 1.0 in normal controls (none had >1.4) and <0.8 in ALS (70% having values <0.6). In conclusion, RSH syndrome may provide valuable diagnostic clues to differentiate this relatively self-restricted disease from progressive degenerative disease like ALS.

Muscle MRI in Duchenne muscular dystrophy: Evidence of a distinctive pattern.

The purpose of this study was to describe the pattern of muscle involvement using MRI findings and correlate with functional as well as muscle strength measurements. Fifty genetically confirmed DMD children with a mean age of 7.6 ± 2.8 (4-15 years) underwent muscle MRI and qualitative assessment was done for muscle changes using Mercuri staging for fibro-fatty replacement on T1 sequence and Borsato score for myoedema on STIR sequence. Detailed phenotypic characterisation was done with Manual muscle testing (modified MRC grading) and Muscular Dystrophy Functional Rating Scale (MDFRS). Mercuri scoring showed severe fibro-fatty changes in Gluteus medius, minimus and Adductor magnus followed by moderate to severe changes in Gluteus maximus and Quadriceps muscles. Total sparing of Gracilis, Sartorius and Semimembranosus muscles was observed. Superficial posterior and lateral leg muscles were preferentially involved with sparing of deep posterior and anterior leg muscles. Myoedema showed significant inverse correlation with fatty infiltration in thigh muscles. Similarly, significant inverse correlation was observed between Mercuri scores and MRC grading as well as MDFRS scores. A direct linear correlation was observed between duration of illness and fibro-fatty changes in piriformis, quadriceps and superficial posterior leg muscles. There was no correlation between MRI findings and genotypic characteristics. However, this specific pattern of muscle involvement in MRI could aid in proceeding for genetic testing when clinical suspicion is high, thus reducing the need for muscle biopsy. Fibro fatty infiltration as measured by Mercuri scoring can be a useful marker for assessing the disease severity and progression.

Duchenne Muscular Dystrophy and Becker Muscular Dystrophy Confirmed by Multiplex Ligation-Dependent Probe Amplification: Genotype-Phenotype Correlation in a Large Cohort

Background and Purpose Studies of cases of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) confirmed by multiplex ligation-dependent probe amplification (MLPA) have determined the clinical characteristics, genotype, and relations between the reading frame and phenotype for different countries. This is the first such study from India. Methods A retrospective genotype-phenotype analysis of 317 MLPA-confirmed patients with DMD or BMD who visited the neuromuscular clinic of a quaternary referral center in southern India. Results The 317 patients comprised 279 cases of DMD (88%), 32 of BMD (10.1%), and 6 of intermediate phenotype (1.9%). Deletions accounted for 91.8% of cases, with duplications causing the remaining 8.2%. There were 254 cases of DMD (91%) with deletions and 25 (9%) due to duplications, and 31 cases (96.8%) of BMD with deletions and 1 (3.2%) due to duplication. All six cases of intermediate type were due to deletions. The most-common mutation was a single-exon deletion. Deletions of six or fewer exons constituted 68.8% of cases. The deletion of exon 50 was the most common. The reading-frame rule held in 90% of DMD and 94% of BMD cases. A tendency toward a lower IQ and earlier wheelchair dependence was observed with distal exon deletions, though a significant correlation was not found. Conclusions The reading-frame rule held in 90% to 94% of children, which is consistent with reports from other parts of the world. However, testing by MLPA is a limitation, and advanced sequencing methods including analysis of the structure of mutant dystrophin is needed for more-accurate assessments of the genotype-phenotype correlation.

Proximal and proximo-distal bimelic amyotrophy: Evidence of cervical flexion induced myelopathy

Abstract This report aims at describing two new clinical phenotypes associated with classical features of cervical flexion induced myelopathy (CFIM). The description is of a prospective case series of six young males presenting with progressive bilateral proximal/proximo-distal amyotrophy of upper limbs and demonstrating the typical MRI characteristics of Hirayama disease. All underwent detailed clinical, electrophysiologcal and imaging studies. The affected muscles were shoulder girdles and arms in proximal form (n = 2) and the entire upper limbs in proximo-distal form (n = 4). The mean age at onset was 21.0 ± 3.3 years, duration of illness was 6.7 ± 3.4 years, period of progression was 39.0 ± 27.3 months followed by a stable phase of 45.0 ± 50.0 months. All had severe wasting and weakness of affected muscles leading to significant disability. Nerve conduction studies revealed grossly reduced compound muscle action potential amplitudes with neurogenic pattern on electromyography of affected muscles. On MRI all revealed evidence of cervical cord atrophy with signal changes, dural detachment and extensive posterior epidural enhancement (variably from C1 to T2 level). Altered cervical curvature was prominent. In conclusion, hitherto unreported, we describe two additional clinical phenotypes (proximal and proximo-distal forms) of Hirayama disease demonstrating the cardinal imaging features of CFIM.

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.

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.

Natural history of a cohort of Duchenne muscular dystrophy children seen between 1998 and 2014: An observational study from South India

Background: Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy. There are no large studies describing its natural course from India. Materials and Methods: Immunohistochemically/genetically confirmed DMD patients diagnosed between 1998 and 2014 were ambispectively included. The main aim was to study the natural course of motor milestones, i.e., age at onset of wheelchair status, bedbound state, and age at death, which were considered as primary outcome measures. We also correlated the DMD genotype with the motor milestones and other phenotypic features. Results: A total of 500 DMD patients were included and 275 participated in the study. The mean age at symptom onset was 3.7 ± 1.9 years, mean age at presentation was 8.1 ± 2.5 years, and mean duration of illness was 4.4 ± 2.6 years. On following them over 15 years, 155 (56.4%) had attained at least one of the primary outcome measures. Wheelchair status was attained in 124 (45.1%) [mean age: 10.4 ± 1.6 years] and bedbound state in 24 (8.7%; mean age: 11.8 ± 2.2 years) patients. Seven patients (2.6%) died during the follow-up period (mean age: 15.2 ± 2.4 years). There was no significant impact of the genotypic or phenotypic features on the primary outcome. Conclusion: The pattern of major motor milestones (primary outcome measures) in this large cohort is comparable with that of the Western population despite variability in medical care. The genotypic pattern was also similar to other large studies, which suggests that DMD is a more homogeneous disorder with limited ethnic variability in its geno-phenotypic expression.

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

Abstract 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.

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

Abstract 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.

CARASIL families from India with 3 novel null mutations in theHTRA1gene

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) (MIM 600142) is linked to homozygous mutations in the high-temperature requirement A serine peptidase 1 gene (HTRA1).1 The triad includes alopecia, spondylosis deformans, and young-adult onset dementia following leukoaraiosis caused by cerebral small-vessel disease (CSVD).2 Although CARASIL originally was considered to be a recessive disorder and monoethnic, restricted to Japan, there are several reports of genetically confirmed cases and a few manifest heterozygotes in other ethnicities, thus expanding the CARASIL paradigm.3–6 In this study, we describe 3 CARASIL families carrying novel null HTRA1 mutations and also the notable phenotypes among the heterozygotes.