Laparoscopic Nissen fundoplication during gastrostomy tube placement and noninvasive ventilation may improve survival in type I and severe type II spinal muscular atrophy

Progressive respiratory muscle weakness with bulbar involvement is the main cause of morbidity and mortality in type I and severe type II spinal muscular atrophy. Noninvasive positive pressure ventilation techniques coupled with laparoscopic gastrointestinal procedures may allow for improved morbidity and mortality. The authors present a series of 7 spinal muscular atrophy patients (6 type I and 1 severe type II) who successfully underwent laparoscopic gastrostomy tube insertion coupled with Nissen fundoplication and early postoperative extubation using noninvasive positive pressure ventilation techniques. The authors measured the length of survival and the frequencies of pneumonia and hospitalization before and after surgery as outcomes of these new surgical and medical interventions. All 7 patients had respiratory symptoms (unmanageable oropharyngeal secretions, cough, pneumonia), difficulty feeding, and weight loss. Six patients had documented reflux via diagnostic testing preoperatively. Five patients were on noninvasive positive pressure ventilation and other supportive respiratory therapies prior to surgery. All 7 patients survived the procedures. By August 2006, 5 patients with type I and 1 with severe type II spinal muscular atrophy were alive and medically stable at home 1.5 months to 41 months post-op. One patient with type I expired approximately 5 months post-op due to obstructive apnea. This case series demonstrates that laparoscopic gastrostomy tube placement coupled with Nissen fundoplication and noninvasive positive pressure ventilation can be successfully used as a treatment option to allow for early postoperative extubation and to optimize quality of life in type I and severe type II spinal muscular atrophy patients.

Medical considerations of long-term survival of Werdnig-Hoffmann disease

OBJECTIVES

To report intercurrent nonrespiratory complications of unprecedented survival for Werdnig-Hoffman disease (spinal muscular atrophy type 1 [SMA 1]).

DESIGN

A retrospective chart review and caregiver questionnaire for 103 consecutively referred SMA 1 patients for whom death was prevented during infancy.

RESULTS

Overall, 15 of 63 (23.8%) respondents had severe, symptomatic bradycardias. Thirteen of 25 males had bilateral cryptorchidism, and two were unilateral. Ten of 42 (24%) respondents had recurrent oral candidiasis, and eight (19.0%) had recurrent nonoral candidiasis. All patients had hip dislocation/subluxation. They had collapsing spines and scoliosis by 1 yr of age. Ninety-six had indwelling gastrostomy/nasogastric tubes before 24 mos of age. Twenty-six underwent fundoplication to decrease reflux. Fifty-seven were on modified elemental diets with reported benefits. About one half had early pubarche. Three patients had episodes of acute pancreatitis. One untreated patient died of candidal endocarditis at 4 mos of age, and a second child had mitral valve candidiasis on autopsy.

CONCLUSION

Prolonged survival of SMA 1 results in a high incidence of concomitant medical conditions that need to be addressed.

Long-term survival in Werdnig-Hoffmann disease

OBJECTIVES

To report long-term survival of spinal muscular atrophy type 1 (SMA 1) and consequences on speech and ventilator dependence as a function of mode of ventilator use.

DESIGN

A retrospective chart review of 106 consecutively referred SMA 1 patients, the 92 most severe of which were considered in three groups: untreated (group 1), tracheostomy managed (group 2), and noninvasively managed (group 3).

RESULTS

The untreated patients died at 9.6 +/- 4.0 mos of age. The mean age of the 22 patients referred with tracheostomy tubes (group 2) was 70.5 +/- 43.3 mos (range 2-159 mos); five died at 66.2 +/- 114.2 mos (range 8-270 mos) of age. Six had comprehendible speech at the time of tracheotomy and retained some ability to vocalize afterward. None of the 21 patients who had not developed the ability to speak did so after tracheotomy. Twenty-five of the 27 total lost all autonomous breathing ability immediately, and definitively, after tracheotomy. The 47 patients who used noninvasive mechanical ventilation (NIV) (group 3) were extubated to it during episodes of acute respiratory failure. Thirty-nine of these were 65.2 +/- 45.8 mos (range 11-153 mos) of age, and eight died at 60.9 +/- 26.1 mos (range 36-111 mos) of age. There was no significant difference in longevity with or without tracheostomy, but the NIV patients had significantly fewer (P = 0.04) hospitalizations per year after age 5; 39 of the 47 could communicate verbally, and only nine were continuously dependent on NIV.

CONCLUSIONS

NIV and tracheostomy can both prolong survival for SMA 1 patients, but the latter results in continuous ventilator dependence and speech does not develop.

[Effect of thoracic bracing on lung function in children with neuromuscular disease]

Respiratory muscle weakness associated with scoliosis in neuromuscular disease leads to respiratory impairment. Children with scoliosis are usually treated with spinal bracing to delay the progress of disease. We studied the impact of spinal bracing on lung function in these children.

METHODS

Retrospective study of patient data from January 1997 to January 2003. Spirometry and measurement of lung volume involved 32 observations, corresponding to 17 children with neuromuscular disease, including 14 with spinal muscular atrophy. Data for children with and without a brace were studied.

RESULTS

A total of 72% of the children had severe scoliosis (Cobb score>30 degrees ); 40% wore a Garchois brace. Children without a brace showed a mean vital capacity of 65% of predicted value, with a restrictive syndrome in 44% of observations. Children with a brace showed significantly reduced vital capacity (-4.6%; P<0.001) and forced expiratory volume in 1 s (-4.6%; P=0.002). The reduced vital capacity was lower in children with the Garchois brace: -1% (P=0.02). Severity of scoliosis and measured volumes were not related.

CONCLUSION

Spinal bracing in children with neuromusclar disease leads to significant respiratory impairment. Assessment of pulmonary function is necessary when a brace is indicated. The Garchois brace might lead to less impairment of respiratory function.

The Hammersmith functional score correlates with the SMN2 copy number: a multicentric study

Previous studies showed that SMN2 copy number correlates inversely with the disease severity. Our aim was to evaluate SMN2 copy numbers and the Hammersmith functional motor scale in 87 patients with SMA II in order to establish whether, within SMAII, the number of copies correlates with the severity of functional impairment. Our results showed a relative variability of functional scores, but a significant correlation between the number of SMN2 genes and the level of function.

Noninvasive Ventilation in Children with Spinal Muscular Atrophy Types 1 and 2

OBJECTIVE

Our aim was to assess the efficacy of noninvasive ventilation (NIV) for the treatment of thoracoabdominal asynchrony during sleep in children with spinal muscular atrophy (SMA) types 1 and 2.

DESIGN

Nine subjects underwent assessment for sleep apnea/hypopnea index (AHI), mean oxyhemoglobin saturation (SpO2), oxygen desaturation index, transcutaneous carbon dioxide tension (tcpCO2), and mean phase angle during sleep as a measure of thoracoabdominal coordination. A second sleep study was performed with use of NIV.

RESULTS

The nine patients (7 mos of age, range 2-33) had a baseline AHI of 2.1 events per hour (range 0.5-55.8), oxygen desaturation index of 3.7 events per hour (range 1.6-46.1), mean tcpCO2 of 46 mm Hg (range 37-60), and phase angle of 127 degrees (range 72.7-151.7). Comparing baseline and NIV sleep studies, we found significant improvement in oxygen desaturation index (P < 0.010), mean tcpCO2 (P < 0.001), and phase angle (P < 0.001). For five patients, phase-angle improvement became significant when using high-span bilevel positive airway pressure (PAP).

CONCLUSIONS

NIV improved sleep breathing parameters and thoracoabdominal coordination during sleep in SMA types 1 and 2. Phase-angle improvement correlated with bilevel PAP pressures. Phase angle may be useful for the evaluation and monitoring of therapeutic interventions such as NIV.

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.

Severe childhood SMA and axonal CMT due to anticodon binding domain mutations in the GARS gene

We screened 100 patients with inherited and sporadic lower motor neuron degeneration and identified three novel missense mutations in the glycyl-tRNA synthetase (GARS) gene. One mutation was in the anticodon binding domain and associated with onset in early childhood and predominant involvement of the lower limbs, thus extending the phenotype associated with GARS mutations.

Atypical presentations of spinal muscular atrophy type III (Kugelberg-Welander disease)

Spinal muscular atrophy type III (SMA III, Kugelberg-Welander disease) typically presents with symmetric proximal weakness, areflexia, and hypotonia. We present four children with spinal muscular atrophy type III who had atypical phenotypes. Three patients clearly had asymmetric weakness at presentation and two had upper motor neuron signs in the lower extremities (one patient had both features). Two of the patients had prolonged evaluations before the diagnosis was made. All patients had Gowers signs and two had pes planus. In patients with proximal muscle weakness the presence of asymmetrical weakness, upper motor neuron signs, or both, may be compatible with spinal muscular atrophy type III. The diagnosis of spinal muscular atrophy should be considered when other possibilities have been excluded.

A modified Hammersmith functional motor scale for use in multi-center research on spinal muscular atrophy

The Hammersmith functional motor scale for children with spinal muscular atrophy was modified to establish a standard measure of functional ability in children with non-ambulant spinal muscular atrophy types 2 and 3 in a longitudinal multi-center clinical trial. This study assessed the intra- and interrater reliability and the test-retest stability of a modified version of the scale. Both intra- and interrater reliability were established. Results indicate that the scale is reliable and stable over a 6 month period. Reliability was maintained when patient sample criteria were expanded to include children younger than 30 months and children with popliteal angles greater than 20 degrees . These data establish the modified Hammersmith functional motor scale for children with spinal muscular atrophy as a reliable instrument for use in multi-center treatment trials in non-ambulant spinal muscular atrophy children. Our data provides additional support for the use of original scale items in terms of ease of administration, usefulness and reliability, while incorporating modifications to optimize its use in a multi-center clinical research setting.

The gross motor function measure™ is a valid and sensitive outcome measure for spinal muscular atrophy

Spinal muscular atrophy is a genetic disease of the anterior horn cell with high morbidity rate in childhood. Certain drugs may be of benefit and are in or under consideration for Phase II trials. Outcome measures that are age appropriate and representative of disease activity remain under study. Several have not yet been validated for spinal muscular atrophy. The Gross Motor Function Measure is a measure of motor function. We showed previously that the Gross Motor Function Measure is a reliable outcome measure to assess motor function in children with spinal muscular atrophy. By collating our data from 40 spinal muscular atrophy patients, ages 5 through 17 years, we now show the validity of the Gross Motor Function Measure when compared to Quantitative Muscle Testing and ambulatory status in children with spinal muscular atrophy. The median for Gross Motor Function Measure total scores for walkers was 237 (range: 197-261) and for non-walkers, 64 (range: 4-177; P<0.0001) with no distributional overlap. We conclude that the Gross Motor Function Measure is valid and sensitive as an outcome measure for clinical trials in pediatric spinal muscular atrophy.

Morphological and morphometrical study of human muscle spindles in Werdnig-Hoffmann disease (infantile spinal muscular atrophy type I)

A study was made of the morphological and morphometrical features of muscle spindles in biopsies of patients with Werdnig-Hoffmann disease (infantile spinal muscular atrophy type I) to investigate the possible involvement of the muscle spindles in the pathological processes of the disease. A total of 57 muscle spindles from 26 cases were studied. The parameters determined were: the diameter and area of spindles, the number, diameter and area of intrafusal fibers, the number and area of nuclei. In addition, the ratio of the area of the intrafusal fibers to the area of nuclei and the ratio of the area of the spindle to the area of the intrafusal fibers were calculated. Statistical evaluation of the data showed significant differences regarding the area of the muscle spindle, the diameter of the intrafusal fibers and the mean area of nuclei of the intrafusal fibers, which were all smaller in patients than in controls (p=0.03, 0.01 and 0.02, respectively), while the thickness of the capsule was greater in patients than in controls (p=0.01). Our results indicate that the muscle spindle participates in the pathological processes of Werdnig-Hoffmann disease.

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.

Respiratory muscle testing: a valuable tool for children with neuromuscular disorders

RATIONALE

Data on respiratory muscle performance in children with neuromuscular disorders are limited.

OBJECTIVES

The aim of this study was to assess respiratory muscle strength by volitional and nonvolitional tests and to compare these tests with forced vital capacity.

METHODS

Inspiratory muscle strength was assessed by measuring transdiaphragmatic and esophageal pressures generated during volitional and nonvolitional maneuvers, whereas expiratory muscle strength was assessed by measuring the gastric pressure generated during a cough maneuver. Lung volumes were assessed by measuring forced vital capacity.

MEASUREMENTS AND MAIN RESULTS

Forty-one patients with Duchenne muscular dystrophy (n = 20), spinal amyotrophy (n = 8), and congenital myopathy (n = 13) were included, aged 2 to 18 yr. All the patients were able to perform the sniff and the cough maneuver. Sniff transdiaphragmatic pressure decreased with age in Duchenne patients, whereas it increased with age in patients with spinal amyotrophy and congenital myopathy. Magnetic stimulation of the phrenic nerves was obtained in all patients. Twenty-five (61%) patients were able to perform forced vital capacity. In the three groups of patients, a positive correlation was observed between volitional, assessed by the sniff maneuver, and nonvolitional respiratory muscle tests, assessed by the magnetic stimulation of the phrenic nerves. Also, forced vital capacity correlated with sniff transdiaphragmatic pressure and cough gastric pressure.

CONCLUSIONS

Volitional respiratory muscle tests correlated with nonvolitional tests and with forced vital capacity. Simple volitional respiratory muscle tests constitute a valuable tool for the assessment of respiratory muscle strength in young patients with neuromuscular disorders.

Unraveling the genetics of distal hereditary motor neuronopathies

The hereditary motor neuronopathies (HMN [MIM 158590]) are a heterogeneous group of disorders characterized by an exclusive involvement of the motor part of the peripheral nervous system. They are usually subdivided in proximal HMN, i.e., the classical spinal muscular atrophy syndromes and distal hereditary motor neuronopathies (distal HMN) that clinically resemble Charcot-Marie-Tooth syndromes. In this review, we concentrate on distal HMN. The distal HMN are clinically and genetically heterogeneous and were initially subdivided in seven subtypes according to mode of inheritance, age at onset, and clinical evolution. Recent studies have shown that these subtypes are still heterogeneous at the molecular genetic level and novel clinical and genetic entities have been delineated. Since the introduction of positional cloning, 13 chromosomal loci and seven disease-associated genes have been identified for autosomal-dominant, autosomal-recessive, and X-linked recessive distal HMN. Most of the genes involved encode protein with housekeeping functions, such as RNA processing, translation synthesis, stress response, apoptosis, and others code for proteins involved in retrograde survival. Motor neurons of the anterior horn of the spinal cord seems to be vulnerable to defects in these housekeeping proteins, likely because their large axons have higher metabolic requirements for maintenance, transport over long distances and precise connectivity. Understanding the molecular pathomechanisms for mutations in these genes that are ubiquitous expressed will help unravel the neuronal mechanisms that underlie motor neuropathies leading to denervation of distal limb muscles, and might generate new insights for future therapeutic strategies.

Reliability of the Hammersmith functional motor scale for spinal muscular atrophy in a multicentric study

The aim of this study was to validate the Hammersmith functional motor scale for children with spinal muscular atrophy in a large cohort of 90 non-ambulant children with spinal muscular atrophy type 2 or 3. All had a baseline assessment (T0) and were reassessed either at 3 months (T1) (n = 66) or at 6 months (T2) (n = 24). Inter-observer reliability, tested on 13 children among 3 examiners, was > 95%. Of the 66 children examined after 3 months 4 had adverse effects in between assessments and were excluded from the analysis. Forty-two (68%) of the remaining 62 reassessed had no variation in scores between T0 and T1 and 13 (21%) were within +/- 1 point. 9 (37.5%) of the 24 children reassessed after 6 months had no variation in scores between T0 and T2 and another 9 (37.5%) had variations within +/- 1 point. Our study confirms previous observations of the reliability of the scale and helps to establish a baseline for assessing changes of functional ability over 3 and 6 month intervals. This information can be valuable in view of therapeutic trials.

Transplanted ALDHhiSSClo neural stem cells generate motor neurons and delay disease progression of nmd mice, an animal model of SMARD1

Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an infantile autosomal-recessive motor neuron disease caused by mutations in the immunoglobulin micro-binding protein 2. We investigated the potential of a spinal cord neural stem cell population isolated on the basis of aldehyde dehydrogenase (ALDH) activity to modify disease progression of nmd mice, an animal model of SMARD1. ALDH(hi)SSC(lo) stem cells are self-renewing and multipotent and when intrathecally transplanted in nmd mice generate motor neurons properly localized in the spinal cord ventral horns. Transplanted nmd animals presented delayed disease progression, sparing of motor neurons and ventral root axons and increased lifespan. To further investigate the molecular events responsible for these differences, microarray and real-time reverse transcription-polymerase chain reaction analyses of wild-type, mutated and transplanted nmd spinal cord were undertaken. We demonstrated a down-regulation of genes involved in excitatory amino acid toxicity and oxidative stress handling, as well as an up-regulation of genes related to the chromatin organization in nmd compared with wild-type mice, suggesting that they may play a role in SMARD1 pathogenesis. Spinal cord of nmd-transplanted mice expressed high transcript levels for genes related to neurogenesis such as doublecortin (DCX), LIS1 and drebrin. The presence of DCX-expressing cells in adult nmd spinal cord suggests that both exogenous and endogenous neurogeneses may contribute to the observed nmd phenotype amelioration.

Autonomic dysfunction in cases of spinal muscular atrophy type 1 with long survival

In Japan, quite a few patients with spinal muscular atrophy type 1 (SMA type 1) survive with mechanical ventilation. Since a patient with SMA type 1 and continuous artificial ventilation exhibited excessive perspiration and tachycardia, we examined the autonomic functions in three cases of SMA type 1, undergoing mechanical ventilation. Two cases exhibited the common sympathetic-vagal imbalance on R-R interval analysis involving 24-h Holter ECG recordings in addition to an abnormality in finger cold-induced vasodilatation. Furthermore, one case showed blood pressure and heart rate fluctuation with the paroxysmal elevation, and a high plasma concentration of norepinephrine during tachycardia. These findings suggest that autonomic dysfunction should be examined in SMA type 1 patients with long survival, although the pathogenesis remains to be clarified.

Sleep-Disordered Breathing in Spinal Muscular Atrophy Types 1 and 2

OBJECTIVE

Our aim was to assess the respiratory pattern during sleep in patients affected by spinal muscular atrophy types 1 and 2 and to compare their apnea-hypopnea indices with those of controls.

DESIGN

All consecutively referred patients underwent polysomnography. Sleep stages were defined as either wake, quiet sleep (QS), or active sleep (AS). As measures of thoracoabdominal coordination, we measured: phase angle during QS and AS (Ph Angle QS and AS), phase relation during inspiration and expiration during QS and AS: (Ph RIB QS, Ph RIB AS, Ph REB QS; Ph REB AS) and the apnea-hypopnea index.

RESULTS

The 14 consecutively referred infants and small children (age, 11.7 +/- 11.4 mos) showed a higher apnea-hypopnea index (P < 0.001), Ph Angle QS (P < 0.001), Ph Angle AS (P < 0.001), Ph RIB QS (P < 0.001), Ph RIB AS (P < 0.001), Ph REB QS (P < 0.001), and Ph REB AS (P < 0.001) compared with 28 healthy controls (age, 10.1 +/- 8.9 mos).

CONCLUSIONS

Patients affected by types 1 and 2 spinal muscular atrophy had significantly higher apnea-hypopnea indices than controls. Thoracoabdominal asynchrony was present during the inspiratory and expiratory phases in both quiet and active sleep. Measures of thoracoabdominal coordination may be useful for the evaluation and monitoring of therapeutic interventions for these patients.

Physical complaints in ageing persons with spinal muscular atrophy

OBJECTIVE

While life expectancy is improving for persons with spinal muscular atrophy, new physical complaints may arise. To investigate this, we studied persons with a long duration and severe course (high functional limitations) of the disease.

DESIGN

Cross-sectional descriptive study.

SUBJECTS/PATIENTS

Persons with spinal muscular atrophy.

METHODS

Questionnaires and structured interviews on prevalence of physical complaints and their duration. Of 190 questionnaires 99 were returned; of 23 persons (with the longest disease duration and high functional limitation level) selected for structured medical interviews 9 participated.

RESULTS

Patterns common within and different between the different types of spinal muscular atrophy were identified. Of the 10 most common complaints, types 1-2 had a significantly higher prevalence of kyphoscoliosis, difficulty in coughing, joint contractures and voice/speech problems, while type 3 had a significantly higher prevalence of fatigue. No statistically significant correlation was found between the appearance of physical complaints and disease duration. However, sleeping and swallowing problems were in the 5 most common complaints with the shortest mean time of appearance. The structured interview revealed hypermobility in the hand, suffusion of the eyes, and itching as new complaints with high prevalence.

CONCLUSION

There are indications that the frequency of less well-known physical complaints increases with ageing.

[Spinal muscular atrophy. A 4-year prospective, multicenter, longitudinal study (168 cases)]

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterised by motoneuron degeneration in the anterior horn of the spinal cord and in the bulbar nuclei. The various types of SMA are linked to the 5q13 locus in 95 % of cases. In the absence of an effective specific treatment, orthopaedic and respiratory management can significantly improve the prognosis. To study the contemporary natural history of SMA and to identify clinical and non invasive prognostic criteria, 168 patients with SMA were recruited in 6 hospital units (Lille, Lyon, Marseille, Paris) during a 4-year prospective multicenter follow-up study (1998-2002). Follow-up has now lasted at least 4 years in 151 cases (90%), and 24 of these patients have died Disease outcome was appraised by using three criteria: muscle strength, the sum of the motor function and examination index (IFM), the respiratory muscle paralysis index (IMR), and the dorsal decubitus forced vital capacity/theoretical index (ICV/CT). Statistical analysis showed a significant worsening (about 20%) of the three criteria during follow-up. The motor function and examination index (IFM) is particularly interesting: the difference between initial and final status was significant in all age groups and in all three types of the disease. The IFM may thus be useful as the main outcome measure during therapeutic trials.

Type I spinal muscular atrophy can mimic sensory-motor axonal neuropathy

Spinal muscular atrophy is a group of allelic autosomal recessive disorders characterized by progressive motoneuron loss, symmetric weakness, and skeletal muscle atrophy. It is traditionally considered a pure lower motoneuron disorder, for which a current definitive diagnosis is now possible by molecular genetic testing. We report two newborns with a clinical phenotype consistent with that of spinal muscular atrophy type I and nerve conduction studies and electromyography suggesting more extensive sensory involvement than classically described with spinal muscular atrophy. Molecular testing confirmed spinal muscular atrophy in patient 1 but not in patient 2. Thus, in the setting of a suspected congenital axonal neuropathy, molecular testing might be necessary to distinguish spinal muscular atrophy type I from infantile polyneuropathy.

[Spinal muscular atrophy associated with olivopontocerebellar hypoplasia. A case report]

INTRODUCTION

Spinal muscular atrophy is a frequent neurodegenerative disease in infancy. Nevertheless, its association with olivopontocerebellar hypoplasia is rare.

CASE REPORT

We describe a case displaying clinical symptoms that included respiratory failure, dysmorphias, hypotonia, deep tendon areflexia and respiratory complications, like the cases described in the literature. In the genetic study it was not possible to find the motor neuron gene surviving from the infantile muscular atrophy. The neuropathological disorders found in the necropsy study were olivopontocerebellar hypoplasia with intense neuronal loss (fundamentally from Purkinje cells and from the granular layer of the cerebellum, olivary nuclei and pons), replacement gliosis and degeneration of the motor cells in the anterior horn of the spinal cord. Death occurred due to a respiratory complication in the 11th postnatal month.

CONCLUSIONS

The paper describes the clinical-pathological study and the genetic study of a female patient who died at the age of 11 months after being diagnosed as presumably suffering from Werdnig-Hoffman disease. The autopsy revealed an olivopontocerebellar hypoplasia, which is a morphological trait that is not associated with the above-mentioned entity. The microscopic study revealed extensive areas of gliosis and neuronal loss. We conclude with the diagnosis of spinal muscular atrophy associated with olivopontocerebellar hypoplasia, which is a rare clinical entity with very few case reports and whose genetic defect is still unknown. We also review the extant literature related to this case.