Chronic segmental spinal muscular atrophy of upper extremities in identical twins

Flexion MRI in a case of Hirayama disease

We report the case of an 18-year old male with a history of asymmetric weakness and amyotrophy of distal upper extremities, suggestive of Hirayama disease. Magnetic resonance imaging (MRI) of the cervical spine was obtained both in flexion and neutral position. Flexion MRI showed forward displacement of the dura and subsequent cord compression, with associated marked enlargement and postcontrast enhancement of posterior epidural plexus. These findings are pathognomonic of the disorder. On neutral MRI abnormalities may be subtle: in our case, they included loss of physiological lordosis, asymmetric atrophy and increased T2 signal intensity of the lower anterior cervical cord. The ability to identify abnormalities on neutral MRI however is even more important in that it allows the radiologist to include a flexion sequence in the MRI examination, if not specifically requested by the referring physician, and in cases in which the suspicion of the disorder has not been raised.

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.

Benign focal amyotrophy

Within lower motor neuron diseases, benign focal amyotrophy is a rare syndrome characterized by insidious neurogenic asymmetric atrophy restricted to upper or lower limbs with a good prognosis over time. Described under several terms, the nosology is probably heterogeneous. In juvenile distal upper-limbs forms, specific MRI signs with in particular a compression of the spinal cord by forward displacement of dura, lead to evoke a mechanical process. In other forms, occurring later in the life, affecting proximal part of upper limbs or lower limbs, the physiopathology is still unknown and a focal spinal muscular atrophy is suspected. In this review, we will discuss the clinical, electrophysiological and radiological features of each presentation.

Bilateral familial Hirayama disease in a father and daughter

We are reporting a case of bilateral familial Hirayama disease where a father and daughter are the affected members of the family with the similar distribution of their weakness and wasting. To the best of our knowledge, bilateral familial Hirayama disease has not been described in father and daughter.

Juvenile Muscular Atrophy of a Unilateral Upper Extremity (Hirayama Disease) in a Patient with CHARGE Syndrome

CHARGE syndrome is an autosomal dominant congenital anomaly syndrome, and the causative gene is CHD7. We report a patient with a CHD7 mutation who presented with juvenile muscular atrophy of a unilateral upper extremity, a presumably heterogeneous condition that is also known as Hirayama disease. This association has not been previously described. Weakness and atrophy of the hands should be carefully examined in patients with CHARGE syndrome, since Hirayama disease might be a possible complication in adolescent patients with this syndrome.

Investigation of the role of SMN1 and SMN2 haploinsufficiency as a risk factor for Hirayama's disease: Clinical, neurophysiological and genetic characteristics in a Spanish series of 13 patients

OBJECTIVE

The effect of the number of copies in the SMN1 and SMN2 genes - the most extensively studied susceptibility and modifying genetic factors in adult onset motor neuron diseases - as a genetic risk factor for Hirayama's disease (HirD) has never been studied. The purpose of this study was to investigate the influence of the number of copies of the SMN1/SMN2 genes on the resulting phenotype in 13 HirD Spanish patients.

PATIENTS AND METHODS

We performed a qualitative and quantitative SMN1/SMN2 gene analysis in 13 unrelated HirD patients. The phenotype-genotype correlation was investigated, paying particular attention to the effect of the SMN1/SMN2 copy number on the disease's phenotype.

RESULTS

No patient had a homozygous deletion of the SMN1 or SMN2. No differences were found when comparing the SMN1 and SMN2 copy number distributions of the healthy population and HirD patients, and they do not therefore appear to be a susceptibility factor. There was also no correlation found between the number of copies of the SMN1 and SMN2 and the severity of the resulting phenotype.

CONCLUSION

Our results suggest that SMN1 and SMN2 are not predisposing factors for HirD and therefore support a lack of association between these genes and the resulting phenotype.

Monomelic neurogenic syndromes: a prospective study

Monomelic neurogenic syndromes are rare. Their classification and prognostic features have not been addressed in the European population. A prospective study of 17 patients with monomelic neurogenic amyotrophy, of upper or lower limb onset, with progression limited to one limb for three or more years. Clinical and neurophysiological studies were performed in the subsequent 3 or more years. Fifteen patients were of European origin and two were Asian. Those presenting with proximal monomelic weakness or with involvement of the posterior compartment of the lower leg showed no further progression after the initial period of development of the syndrome. Brisk reflexes in wasted muscles did not predict progression. Electromyographic signs of denervation in the opposite limb at presentation did not predict later progression. Transcranial magnetic stimulation (TMS) features of corticospinal dysfunction were a useful predictor of subsequent progression (p=0.01). One patient with lower limb onset developed conduction block with weakness in an upper limb nine years after presentation, and this upper limb weakness responded to IVIg therapy. This adult-onset European group of patients is different as compared with juvenile-onset Asian cases. The clinical syndromes appear heterogeneous, but neurophysiological investigations, in particular TMS, can be helpful in determining prognosis. Multifocal motor neuropathy should be considered when there is progression, even years after onset.

Nonprogressive juvenile-onset spinal muscular atrophy: A clinico-radiological and CAG repeat study of androgen receptor gene

BACKGROUND

Occurrence of nonprogressive juvenile-onset spinal muscular atrophy (SMA) predominantly in males suggests a possibility of X-linked disorder but there is no such report addressing this problem.

AIMS

To evaluate CAG repeat expansion of androgen receptor (AR) gene in patients with nonprogressive juvenile-onset SMA.

SETTING

Tertiary medical teaching institute.

SUBJECTS AND METHODS

Patients fulfilling the diagnostic criteria of nonprogressive juvenile-onset SMA were included. Detailed clinical evaluation and pedigree charting were done in all. Nerve conduction study, electromyography and cervical spinal MRI were carried out. From peripheral venous blood, DNA was separated and AR gene CAG repeat exon polymorphism was assayed using polymerase chain reaction (PCR) in conjugation with genotyping and Gene scan soft ware. Number of CAG repeats was compared with normal controls.

RESULTS

25 patients with nonprogressive juvenile-onset SMA from 24 families were included and their mean age was 22.2 years. Age at the time of disease onset ranged between 15 and 30 years with a mean duration of illness 2.6 years. None of the patients had testicular atrophy or gynecomastia. C7-T1 myotomal wasting and weakness although was unilateral to begin with but became bilateral in 16 and 4 more patients had evidences of subclinical involvement of the other side as revealed by EMG. Spinal MRI revealed cord atrophy at C6-8 vertebral level in 16 patients. CAG repeat study of AR gene was carried out in 16 patients. The number of CAG repeats in patients ranged between 15 and 39 (median 21) which were within the normal range.

CONCLUSION

Abnormal CAG repeat expansion of AR gene is not found in patients with nonprogressive juvenile-onset SMA.

Effect of neck flexion on F wave, somatosensory evoked potentials, and magnetic resonance imaging in Hirayama disease

BACKGROUND

Flexion myelopathy is one of the suggested mechanism for Hirayama disease (HD) but simultaneous radiological and neurophysiological evaluation is lacking. This study therefore evaluates the effect of neck flexion in HD using somatosensory evoked potentials (SEPs), F waves, and magnetic resonance imaging (MRI).

METHOD

Eight HD patients and seven matched controls were subjected to median and ulnar F wave (minimal latency, FM ratio, persistence, and chronodispersion), and SEPs evaluating N9, N13, and N20 potentials in neutral and neck flexion. Spinal MRI was carried out in neutral and neck flexion and evaluated for cord atrophy, signal changes, cord compression, posterior epidural tissue, and loss of dural attachment.

RESULTS

The patients were aged 19 to 30 years. Minimal F latency, FM ratio, persistence, and chronodispersion in neutral and neck flexion did not show any change nor was there any change in N13 latency and amplitude on median and ulnar SEPs. The difference in these parameters in neutral and neck flexion were also not significant in HD compared with controls. The change in N13 was also not related to loss of dural attachment and posterior epidural tissue.

CONCLUSION

Neck flexion does not produce significant changes in N13 and F wave parameters and is not related to dynamic MRI changes. The other mechanisms for HD should therefore be explored.

Familial monomelic amyotrophy: a case report from India

Monomelic amyotrophy (MMA) is a benign lower motor neuron disorder in the young with male preponderance. It is characterized by insidious onset and progressive weakness and wasting of a distal extremity over a few years followed by spontaneous arrest. The exact pathogenesis is unknown. It is predominantly a sporadic disorder but rarely familial forms have been documented. In this report, we describe the phenotype of a 21-year-old man and his mother who were diagnosed to have MMA. The index case presented with left upper limb weakness and wasting of 3 years duration while his mother had right upper limb amyotrophy and weakness of 34 years. A total of 190 patients were diagnosed to have MMA in our institute over the last 27 years and this is the first case of familial MMA.

Peripheral and segmental spinal abnormalities of median and ulnar somatosensory evoked potentials in Hirayama's disease

OBJECTIVES

To investigate the origin of juvenile muscle atrophy of the upper limbs (Hirayama's disease, a type of cervical myelopathy of unknown origin).

SUBJECTS

Eight male patients were studied; data from 10 normal men were used as control.

METHODS

Median and ulnar nerve somatosensory evoked potentials (SEP) were recorded. Brachial plexus potentials at Erb's point (EP), dorsal horn responses (N13), and subcortical (P14) and cortical potentials (N20) were evaluated. Tibial nerve SEP and motor evoked potentials (MEP) were also recorded from scalp and spinal sites to assess posterior column and pyramidal tract conduction, respectively.

RESULTS

The most important SEP findings were: a very substantial attenuation of both the EP potentials and the N13 spinal responses; normal amplitude of the scalp N20; and normal latency of the individual peaks (EP-N9-N13-P14-N20). Although both nerves were involved, abnormalities in response to median nerve stimulation were more significant than those in response to ulnar nerve stimulation. There was little correlation between the degree of alterations observed and the clinical state. Latencies of both spinal and cortical potentials were normal following tibial nerve stimulation. The mean latency of cervical MEP and the central conduction time from the thenar eminence were slightly but significantly longer in patients than in controls.

CONCLUSIONS

The findings support the hypothesis that this disease, which is clinically defined as a focal spinal muscle atrophy of the upper limb, may also involve the sensory system; if traumatic injury caused by stretching plays a role in the pathogenesis, the damage cannot be confined to the anterior horn of the spinal cord.

Atypical form of amyotrophic lateral sclerosis

OBJECTIVE

To investigate patients with an unusual type of muscular atrophy confined to the upper limbs (proximally dominant) and the shoulder girdle, while sparing the face and the legs until the terminal stage.

METHODS

Eight patients (six men and two women) were clinically examined. The age at onset ranged from 42 to 73 years, and the clinical course varied from 28 to 81 months. There was no family history of motor neuron disease in any of these patients. Necropsy was performed in two of them.

RESULTS

All eight patients basically showed a similar distribution of muscular weakness and atrophy. Subluxation of the shoulder joints was found in all patients. Reflexes were absent in the upper limbs in all patients, but were almost normal in the face and legs in most patients. Pathological reflexes could be elicited in only one patient. Electromyography showed typical neurogenic changes in the limbs of all patients. Cervical MRI disclosed moderate spondylotic changes in seven patients. Antiganglioside antibodies were negative in six patients tested. Abnormal trinucleotide (CAG) repeat expansion of androgen receptor gene was not recognised in five patients examined. Bulbar involvement developed in three patients during the course of the disease. At necropsy, one patient showed degeneration of the pyramidal tracts and motor cortex including Betz cells as well as loss of spinal anterior horn cells and brainstem motor neurons, which is consistent with ALS; in another patient there was neuronal loss of anterior horn cells at the spinal cord accompanied by astrogliosis, whereas the motor cortex and brainstem motor nuclei were relatively well preserved. Intracytoplasmic inclusions such as Bunina bodies, skein-like inclusions, and Lewy body-like inclusions were found in both patients.

CONCLUSION

These patients with their peculiar pattern of muscular atrophy seem to have ALS or a subtype of ALS.

Cytogenetic analysis of 23 Japanese patients with amyotrophic lateral sclerosis

The cytogenetic analysis of 23 Japanese patients with amyotrophic lateral sclerosis is reported. G-banded chromosomes of cultured peripheral blood lymphocytes of one subject had a constitutional chromosomal translocation, t(7;13)(p22;q21). No constitutional chromosome abnormality was found in any of the other 22 Japanese patients with amyotrophic lateral sclerosis tested.

The wasted leg syndrome, a single fibre electromyographic study of arms and legs

Single fibre electromyography (SFEMG) was performed on 11 patients with the wasted leg syndrome. Five were of South Asian origin and the others Chinese. In most cases the disorder progressed for about 5 yr before becoming static or very slowly progressive. The SFEMG fibre density was increased similarly in both the affected and less affected leg, but was normal in the arms except for a few longstanding cases. The limited extent of clinical and electrophysiological abnormalities suggests that the wasted leg syndrome is a distinct entity.

Congenital cervical spinal muscular atrophy: a non-familial, non progressive condition of the upper limbs

Two patients with congenital cervical spinal muscular atrophy had symmetrical severe muscle weakness and wasting confined to the upper limbs, areflexia and congenital contractures. The shoulders were internally rotated, elbows extended and wrists flexed. There were no sensory or bulbar symptoms, scoliosis, long tract signs or lower limb involvement. This condition should be regarded as a neurogenic type of arthrogryposis, limited to the upper limbs.

Progressive juvenile segmental spinal muscular atrophy

Juvenile segmental spinal muscular atrophy (JSSMA) typically involves the distal upper extremities and follows a benign course over 2-4 years then stabilizes. We report 2 males who presented in their teens with insidious distal upper extremity atrophy and weakness as in typical JSSMA but who then progressed to involvement of the lower extremities and hyperreflexia. There was no sensory loss. Electromyography and muscle biopsy demonstrated features consistent with localized anterior horn cell dysfunction. These patients are noteworthy because they demonstrate that some patients with JSSMA also may have involvement of the lower limbs several years after initial presentation. Progressive JSSMA may be categorized in the clinical spectrum between the spinal muscular atrophies and amyotrophic lateral sclerosis.

Werdnig-Hoffmann disease and chronic distal spinal muscular atrophy with apparent autosomal dominant inheritance

We report on a family in which both Werdnig-Hoffmann disease (severe infantile-onset spinal muscular atrophy) and chronic distal spinal muscular atrophy occurred, with apparent autosomal dominant inheritance. The female proband clinically had Werdnig-Hoffmann disease and died at 10 months. In their second decade of life, the proband's father and his 2 brothers developed bilateral progressive atrophy and weakness of the hands and mild weakness in the distal parts of the legs. Their mother had no symptoms or signs of motor neuron disease but electromyography revealed distal denervation of the limbs. While the family studies suggest autosomal dominant inheritance, it is possible that the proband's condition was influenced by a maternally derived allelic or modifying trait.

Segmental spinal muscular atrophy and dermatological findings in a patient with chromosome 18q deletion

We have evaluated a young woman with segmental spinal muscular atrophy, who has a deletion of a portion of the long arm of chromosome 18. She also has vitiligo and lichen sclerosis et atrophicus. She has neither the facial dysmorphism nor the mental deficit usually associated with the 18q- syndrome. Magnetic resonance imaging scan of her brain demonstrates high signal intensity consistent with abnormal myelination. Southern blot analysis of her DNA demonstrates that the deletion includes the gene for human myelin basic protein. Neither spinal muscular atrophy nor this patient's skin manifestations have been previously reported in association with 18q-.

Monomelic amyotrophy in siblings

Monomelic amyotrophy is a rare, benign motor neuron disorder. Electrophysiologic studies are suggestive of localized chronic anterior horn cell disease. Two young siblings are reported with monomelic amyotrophy who had proximal muscle weakness confined to one arm. We propose that monomelic amyotrophy, at least in this family, is inherited as an autosomal recessive trait.