Clinical correlations and long-term follow-up in 100 patients with sarcoglycanopathies

BACKGROUND AND PURPOSE

To describe a large series of patients with α, β, and γ sarcoglycanopathies (LGMD-R3, R4, and R5) and study phenotypic correlations and disease progression.

METHODS

A multicentric retrospective study in four centers in the Paris area collecting neuromuscular, respiratory, cardiac, histologic, and genetic data. The primary outcome of progression was age of loss of ambulation (LoA); disease severity was established according to LoA before or after 18 years of age. Time-to-event analysis was performed.

RESULTS

One hundred patients (54 γ-SG; 41 α-SG; 5 β-SG) from 80 families were included. The γ-SG patients had earlier disease onset than α-SG patients (5.5 vs. 8 years; p = 0.022) and β-SG patients (24.4 years). Axial muscle weakness and joint contractures were frequent and exercise intolerance was observed. At mean follow-up of 22.9 years, 65.3% of patients were wheelchair-bound (66.7% α-SG, 67.3% γ-SG, 40% β-SG). Dilated cardiomyopathy occurred in all sarcoglycanopathy subtypes, especially in γ-SG patients (p = 0.01). Thirty patients were ventilated and six died. Absent sarcoglycan protein expression on muscle biopsy and younger age at onset were associated with earlier time to LoA (p = 0.021 and p = 0.002). Age at onset was an independent predictor of both severity and time to LoA (p = 0.0004 and p = 0.009). The α-SG patients showed genetic heterogeneity, whereas >90% of γ-SG patients carried the homozygous c.525delT frameshift variant. Five new mutations were identified.

CONCLUSIONS

This large multicentric series delineates the clinical spectrum of patients with sarcoglycanopathies. Age at disease onset is an independent predictor of severity of disease and LoA, and should be taken into account in future clinical trials.

Consensus statement on standard of care for congenital myopathies

Recent progress in scientific research has facilitated accurate genetic and neuropathological diagnosis of congenital myopathies. However, given their relatively low incidence, congenital myopathies remain unfamiliar to the majority of care providers, and the levels of patient care are extremely variable. This consensus statement aims to provide care guidelines for congenital myopathies. The International Standard of Care Committee for Congenital Myopathies worked through frequent e-mail correspondences, periodic conference calls, 2 rounds of online surveys, and a 3-day workshop to achieve a consensus for diagnostic and clinical care recommendations. The committee includes 59 members from 10 medical disciplines. They are organized into 5 working groups: genetics/diagnosis, neurology, pulmonology, gastroenterology/nutrition/speech/oral care, and orthopedics/rehabilitation. In each care area the authors summarize the committee's recommendations for symptom assessments and therapeutic interventions. It is the committee's goal that through these recommendations, patients with congenital myopathies will receive optimal care and improve their disease outcome.

Consensus statement on standard of care for congenital muscular dystrophies

Congenital muscular dystrophies are a group of rare neuromuscular disorders with a wide spectrum of clinical phenotypes. Recent advances in understanding the molecular pathogenesis of congenital muscular dystrophy have enabled better diagnosis. However, medical care for patients with congenital muscular dystrophy remains very diverse. Advances in many areas of medical technology have not been adopted in clinical practice. The International Standard of Care Committee for Congenital Muscular Dystrophy was established to identify current care issues, review literature for evidence-based practice, and achieve consensus on care recommendations in 7 areas: diagnosis, neurology, pulmonology, orthopedics/rehabilitation, gastroenterology/ nutrition/speech/oral care, cardiology, and palliative care. To achieve consensus on the care recommendations, 2 separate online surveys were conducted to poll opinions from experts in the field and from congenital muscular dystrophy families. The final consensus was achieved in a 3-day workshop conducted in Brussels, Belgium, in November 2009. This consensus statement describes the care recommendations from this committee.

[Jeune'disease (asphyxiating thoracic dystrophy) and respiratory failure: importance of early respiratory management with periodic hyperinsufflation]

Asphyxiating thoracic dystrophy (ATD) is a rare autosomal recessive form of chondrodysplasia characterized by short ribs. Respiratory failure is due to the reduced volume and complete immobility of the thoracic cage. There is no consensus on the treatment of this restrictive pulmonary disease. Surgical attempts to enlarge the thoracic cage are disappointing. We report the cases of nine children with ATD treated by periodic respiratory hyperinsufflation. Their clinical outcome was related to the severity of their respiratory distress and their age at the beginning of this treatment. It is possible to use periodic hyperinsufflation very early after birth to prevent secondary respiratory failure. Periodic insufflation can also be used to treat older children with severe restrictive respiratory insufficiency requiring tracheostomy and endotracheal management. This treatment promotes alveolar multiplication and thoracic growth. Four children had laboratory and/or clinical evidence of hepatic dysfunction that improved on ursodeoxycholic acid therapy. Three children who had muscle weakness at birth improved during childhood.

[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.

Respiratory capacity course in patients with infantile spinal muscular atrophy

STUDY OBJECTIVES

To describe the clinical and respiratory course in infantile spinal muscular atrophy (SMA) type I, type II, and type III, and to evaluate the respiratory needs for these patients, using noninvasive or tracheostomy ventilation.

DESIGN

Retrospective cohort study.

METHODS

We report 33 patients with SMA true type I (onset before age 3 months), 35 patients with SMA intermediate type I (onset between 3 months and 6 months), 100 patients with SMA type II (onset between 6 months and 18 months), 12 patients with SMA type III (onset after age 18 months). We report the clinical symptoms, respiratory course, and respiratory management: respiratory physiotherapy, periodic hyperinsufflation, nasal nocturnal ventilation (NNV), and tracheostomy. Also, we measured the FVC over several years during childhood and adolescence.

RESULTS

In patients with SMA true type I, 82% of patients died, one third of whom underwent tracheostomy. In patients with SMA intermediate type I, 43% needed NNV, 57% underwent tracheostomy, and 26% died. In patients with SMA type II, 38% needed NNV, 15% underwent tracheostomy, and 4% died. In patients with SMA type III, respiratory impairment was moderate and began during the second decade of life.

CONCLUSION

This data shows the progressively worsening course of restrictive respiratory insufficiency in patients with SMA, and the importance of early respiratory management to limit pulmonary complications and improve the quality of life for these patients.

Congenital myasthenic syndrome due to rapsyn deficiency: three cases with arthrogryposis and bulbar symptoms

We report the cases of 3 children with postsynaptic congenital myasthenic syndrome with acetylcholine receptor deficiency due to rapsyn deficiency. Symptoms began at the neonatal period with hypotonia, arthrogryposis, bulbar symptoms, and respiratory distress. Two of the 3 children needed tracheostomy and gastrostomy. Electromyograms showed a decremental response to repetitive stimulation. Muscle biopsies were normal or showed type I fiber preponderance. Genetic studies identified mutations in the rapsyn gene (RAPSN). The 3 patients were heterozygous for N88 K and a second mutation (either Y86X, 1083_1084 dupCT or IVS4-2 A > G). The patients responded favorably to anticholinesterase treatment, with a clear improvement of clinical symptoms, especially the bulbar symptoms of apneas and swallowing disturbances. This paper underlines the importance of anticholinesterase medication in patients with congenital myasthenic syndrome due to rapsyn deficiency.

Evoked potentials in spinal muscular atrophy

Visual evoked potentials, brainstem evoked responses, and somatosensory evoked potentials were evaluated in 22 children with spinal muscular atrophy, types I and II. Eleven of the children had the severe form of spinal muscular atrophy (type I) and 11 children had the intermediate form (type II). The results of visual evoked potentials, brainstem evoked responses, and somatosensory evoked potentials were compared with those obtained in a control group. Statistical analysis showed abnormalities in the different sensory modalities. A significant increase in the visual evoked potential latencies was observed and was found more often in patients with spinal muscular atrophy type I. Alterations of the somatosensory thalamocortical responses were also observed, as well as a delay in the central conduction time. Although spinal muscular atrophy is usually considered to be a purely motor disorder involving neurons of the spinal anterior horn and nuclei of the lower cranial nerves, lesions of the posterior roots, spinal ganglia, ascending tracts, lateral geniculated corpus, and thalamus have been reported. Our results suggest that sensory neuron degeneration occurs more commonly in spinal muscular atrophy than previously thought and that this process probably develops more slowly than motoneuron degeneration. Such degeneration may be associated with brain atrophy.

Congenital muscular dystrophy with primary partial laminin alpha2 chain deficiency: molecular study

The authors report a case of congenital muscular dystrophy with mild nonprogressive muscle weakness, white matter hypodensity, and absence of the laminin alpha2 chain in muscle fibers with two antibodies, but not with four others. They identified mutations in LAMA2, which explain the partial laminin alpha2 deficiency. Analysis of this case and two others allows us to refine the epitopes of two of the commercial antibodies, and illustrate the importance of using antibodies directed against different domains of the protein.

Sleep disorders caused by brainstem tumor: case report

Few studies concerning sleep disorders in brainstem lesions or tumors have been published. We report the case of a girl who was operated on for a brainstem tumor at the age of 4 years. In postsurgery, she had hemiparesis of the left side, swallowing difficulties, and severe apneas requiring a tracheotomy with nocturnal ventilation. The child's health improved progressively. Two sleep recordings were performed at 7 and 9 years without nocturnal ventilation. These recordings showed sleep disorders with a decrease in total sleep time and rapid eye movement (REM) sleep. Several central apneas were observed. The apneas were more frequent during REM sleep in the first recording and were associated with desaturation and microarousals.

Jeune syndrome and liver disease: report of three cases treated with ursodeoxycholic acid

Three children with Jeune syndrome (asphyxiating thoracic dystrophy) had clinical and laboratory evidence of liver disease. In two patients the disease evolved to biliary cirrhosis, whereas in the third it was recognized when extensive fibrosis was developing. In the three patients, treatment with ursodeoxycholic acid appeared to control the progression of the hepatic dysfunction.

[Chylothorax complicating a subclavian puncture controlled by positive-pressure expiratory ventilation]

We report a case of traumatic chylothorax which occurred after a right subclavian vein catheterisation. Chyle output exceeded 4 L.day-1 despite a continuous drainage of the pleural space, cessation of oral intake and mechanical ventilation. It was cured by addition of PEP to ventilation. The various causes and therapeutic approaches are reviewed.