[Clinical features of congenital myasthenic syndrome in Japan].

OBJECTIVE: We examined the clinical and neurophysiological features of Japanese patients with congenital myasthenic syndrome (CMS). METHOD: Subjects were five patients who were diagnosed with CMS on the basis of clinical course, repetitive nerve stimulation (RNS), and genetic analysis. RESULTS: Four patients manifested motor retardation within one year of birth, while one manifested motor intolerance at three years of age. The most characteristic symptom observed in all the patients was fluctuating muscle weakness, which varied on a daily basis or continued for several days after the late infancy period. Only one patient manifested daily fluctuation of muscle weakness. RNS of the accessory nerve evoked a decrementing response in three patients who were examined;however, RNS of the median, ulnar, and tibial nerves (one patient each) did not evoke such responses. After the edrophonium chloride test, no improvement was seen even if the patients manifested ptosis. For judgment of this test, improvement in decrementing rate observed while performing RNS was useful. All five patients who were administered medication based on the results of genetic analysis demonstrated an improvement in their symptoms. CONCLUSION: We suggest that CMS can be diagnosed based on careful examination and electrophysiological results. CMS is a treatable disorder, and therefore, correct diagnosis is important.

A novel mutation in the LMNA gene causes congenital muscular dystrophy with dropped head and brain involvement.

We describe a 22-month-old girl with axial muscle and diaphragmatic weakness as well as motor developmental delay without mental retardation. The striking clinical feature was a dropped head, although she could walk unaided. T2/FLAIR brain MRI revealed a focal abnormality with high signal intensity in the white matter including U-fibers. A muscle biopsy showed active necrotic and regenerative processes. These distinct clinical findings prompted a mutational analysis of the lamin A (LMNA) gene, and we identified a novel heterozygous mutation in LMNA (c.1330_1338dup9). This is the first report of an Asian patient with LMNA-related congenital muscular dystrophy (L-CMD) and a dropped head.

Congenital lower brachial plexus palsy due to cervical ribs.

Congenital brachial plexus palsy (CBPP) usually occurs secondarily to intrapartum trauma, but this is not always the case. Cervical ribs have previously been reported to increase the risk of CBPP in association with birth trauma. We report the cases of two children (one female, one male) with congenital lower brachial plexus palsy in whom the presence of non-ossified cervical ribs was the only identified risk factor. In the female child magnetic resonance imaging (MRI) of the brain, spinal cord, and brachial plexus revealed no abnormality except for the presence of bilateral cervical ribs at the level of the seventh cervical (C7) vertebra. Chest radiography was normal, which suggested that the cervical ribs identified on the MRI were fibrous bands or cartilaginous ribs rather than ossified ribs. In the male child, MRI of the spine and brachial plexus was normal but he was noted to have bilateral cervical ribs at C7. These were not identifiable on chest radiography and, therefore, are likely to reflect fibrous bands or cartilaginous ribs.

Identification of candidate genes for congenital splay leg in piglets by alternative analysis of DNA microarray data.

The congenital splay leg syndrome in piglets is characterized by a temporarily impaired functionality of the hind leg muscles immediately after birth. Etiology and pathogenetic mechanisms for the disease are still not well understood. We compared genome wide gene expression of three hind leg muscles (M. adductores, M. gracilis and M. sartorius) between affected piglets and their healthy littermates with the GeneChip Porcine Genome Array (Affymetrix) in order to identify candidate genes for the disease. Data analysis with standard algorithms revealed no significant differences between both groups. By application of an alternative approach, we identified 63 transcripts with differences in two muscles and 5 genes differing between the groups in three muscles. The expression of six selected genes (SQSTM1, SSRP1, DDIT4, ENAH, MAF, and PDK4) was investigated with SYBRGreen RT-Real time PCR. The differences obtained with the microarray analysis could be confirmed and demonstrate the validity of the alternative approach to microarray data analysis. Four genes with different expression levels in at least two muscles (SQSTM1, SSRP1, DDIT4, and MAF) are assigned to transcriptional cascades related to cell death and may thus indicate pathways for further investigations on congenital splay leg in piglets.

Differential diagnosis of congenital muscular dystrophies.

Congenital muscular dystrophies (CMDs) are defined by signs of muscle weakness in the first 6 months of life with myopathic changes in muscle biopsy. The progress in the last decade has helped to make molecular and genetic diagnoses in the majority of patients fulfilling these criteria. In a number of patients a definite diagnosis cannot be reached and these individuals are often grouped together as "merosin positive" congenital muscular dystrophy. In the last 5 years, 25 patients referred for assessment as possible congenital muscular dystrophy have been found to have alternative diagnoses. This paper aims to highlight these conditions as the common differentials or more difficult to diagnoses to consider in patients presenting as CMD.

Abnormal sensorimotor integrative function of the larynx in congenital laryngomalacia: a new theory of etiology.

OBJECTIVES/HYPOTHESIS: Laryngomalacia is an enigmatic disease in which laryngeal tone is weak, resulting in dynamic prolapse of tissue into the larynx. Sensorimotor integrative function of the brainstem and peripheral reflexes are responsible for laryngeal tone and airway patency. The goal of this study was to elucidate the etiology of decreased laryngeal tone through evaluating the sensorimotor integrative function of the larynx. The secondary goal was to evaluate factors and medical comorbidities that contribute to the wide spectrum of symptoms and outcomes. STUDY DESIGN: Prospective and retrospective collection of evaluative data on infants with congenital laryngomalacia at two tertiary care pediatric referral centers. METHODS: Two hundred one infants with laryngomalacia were divided into three groups on the basis of disease severity (mild, moderate, severe). Patients were followed prospectively every 8 to 12 weeks until symptom resolution or loss to follow-up. Sensorimotor integrative function of the larynx was evaluated in 134 infants by laryngopharyngeal sensory testing (LPST) of the laryngeal adductor reflex (LAR) by delivering a duration- (50 ms) and intensity- (2.5-10 mm Hg) controlled air pulse to the aryepiglottic fold to induce the LAR. Medical records were retrospectively reviewed for medical comorbidities. RESULTS: The initial LPST was higher (P < .001) in infants with moderate (6.8 mm Hg) and severe disease (7.4 mm Hg) compared with those with mild disease (4.1 mm Hg). At 1, 3, and 6 months, infants with moderate and severe disease continued to have a higher LPST compared with those with mild disease. At 9 months, the LPST decreased in all subjects (3.1-3.5 mm Hg, P = .14), which also correlated with symptom resolution. Neurologic, genetic, and cardiac diseases were more common in infants with severe disease (P < .001). Gastroesophageal reflux disease (GERD) and feeding problems more common in those with moderate and severe disease (P < .001). Apgar scores were lower in those with severe disease (P < .001). Most symptoms resolved within 12 months of presentation. Those with GERD benefited from treatment. Supraglottoplasty resulted in few complications. Multiple comorbidities (>3) influenced the need for tracheotomy. CONCLUSIONS: Laryngeal tone and sensorimotor integrative function of the larynx is altered. The degree of alteration correlated with disease severity, indicating that factors that alter the peripheral and central reflexes of the LAR have a role in the etiology of signs and symptoms of laryngomalacia. GERD, neurologic disease, and low Apgar scores influenced disease severity and clinical course, explaining the spectrum of disease symptoms and outcomes. Sensorimotor integrative function improved as symptoms resolved.

A congenital myopathy with diaphragmatic weakness not linked to the SMARD1 locus.

Severe diaphragmatic weakness in infancy is rare. Common causes include structural myopathies, neuromuscular transmission defects, or anterior horn cell dysfunction (spinal muscular atrophy with respiratory distress, SMARD1). We describe a form of infantile diaphragmatic weakness without mutations in the SMARD1 gene, in which pathological and clinical features differ from known conditions, and investigations suggest a myopathy. We identified seven cases in four families. All presented soon after birth with feeding and breathing difficulties, marked head lag, facial weakness, and preserved antigravity movements in the limbs, with arms weaker than legs. All had paradoxical breathing and paralysis of at least one hemi-diaphragm. All required gastrostomy feeding, and all became ventilator-dependent. Investigations included myopathic EMG, muscle biopsy showing myopathic changes, normal electrophysiology and no mutations in SMN1 or IGHMBP2. These seven infants are affected by a myopathic condition clinically resembling SMARD1. However, its pathogenesis appears to be a myopathy affecting predominantly the diaphragm.

Facioscapulohumeral dystrophy presenting as infantile facial diplegia and late-onset limb-girdle myopathy in members of the same family.

We report a family with markedly variable myopathic weakness due to facioscapulohumeral muscular dystrophy (FSHD). The proband developed mild late-onset proximal limb weakness. Her two daughters had severe infantile facial diplegia, initially diagnosed as Möbius syndrome, and mild childhood-onset limb weakness and scapular winging. Results of facial muscle electromyography and muscle histopathology supported a myopathic disorder. This case study further highlights the broad clinical spectrum and intrafamily variability in FSHD, and the occasional absence of a positive correlation between fragment size and disease onset. Moreover, this study underscores the importance of considering FSHD in cases of infantile facial diplegia, especially in patients not demonstrating the full clinical features of Möbius syndrome. In difficult cases, facial muscle electromyography may help to differentiate myopathic from neuropathic weakness, and help guide further diagnostic studies.

A case of severe congenital chronic inflammatory demyelinating polyneuropathy with complete spontaneous remission.

Chronic inflammatory demyelinating polyneuropathy (CIPD) is characterised by progressive weakness, hyporeflexia and electrophysiological evidence of demyelination with maximal neurological deficit reached after at least 8 weeks progression. CIPD rarely affects children. We present a neonate with clinical features compatible with congenital CIPD. A term male infant of non-consanguineous parents was referred to us at birth with weakness and contractures affecting his legs, suggesting a prenatal onset of immobility. He also had evidence of bulbar dysfunction with poor suck, recurrent aspiration and requiring nasogastric feeding. He had no antigravity movements in the legs, bilateral wrist drop, distal joint contractures and absent deep tendon reflexes. Electromyography showed neurogenic changes, with nerve conduction velocities markedly reduced, increased distal motor latency and dispersed compound muscle action potentials. Cerebrospinal fluid protein was raised. Sural nerve biopsy demonstrated decreased numbers of myelinated fibres and inflammatory cell infiltrates. Muscle biopsy showed denervation. He only received supportive treatment and by 6 months he had fully recovered, and all electrophysiological parameters had normalised.

A review of 35 cases of asymmetric crying facies.

A review of 35 cases of asymmetric crying facies: Congenital asymmetric crying facies (ACF) is caused by congenital hypoplasia or agenesis of the depressor anguli oris muscle (DAOM) on one side of the mouth. It is well known that this anomaly is frequently associated with cardiovascular, head and neck, musculoskeletal, respiratory, gastrointestinal, central nervous system, and genitourinary anomalies. In this article we report 35 ACF patients (28 children and 7 adults) and found additional abnormalities in 16 of them (i.e. 45%). The abnormalities were cerebral and cerebellar atrophy, mega-cisterna magna, mental motor retardation, convulsions, corpus callosum dysgenesis, cranial bone defect, dermoid cyst, spina bifida occulta, hypertelorism, micrognatia, retrognatia, hemangioma on the lower lip, short frenulum, cleft palate, low-set ears, preauricular tag, mild facial hypoplasia, sternal cleft, congenital heart defect, renal hypoplasia, vesicoureteral reflux, hypertrophic osteoarthropathy, congenital joint contractures, congenital hip dislocation, polydactyly, and umbilical and inguinal hernia. Besides these, one infant was born to a diabetic mother, and had atrial septal defect and the four other children had 4p deletion, Klinefelter syndrome, isolated CD4 deficiency and Treacher-Collins like facial appearance, respectively Although many of these abnormalities were reported in association with ACF, cerebellar atrophy, sternal cleft, cranial bone defect, infant of diabetic mother, 4p deletion, Klinefelter syndrome, isolated CD4 deficiency and Treacher-Collins like facial appearance were not previously published.

Human aldolase A natural mutants: relationship between flexibility of the C-terminal region and enzyme function.

We have identified a new mutation in the FBP (fructose 1,6-bisphosphate) aldolase A gene in a child with suspected haemolytic anaemia associated with myopathic symptoms at birth and with a subsequent diagnosis of arthrogryposis multiplex congenita and pituitary ectopia. Sequence analysis of the whole gene, also performed on the patient's full-length cDNA, revealed only a Gly346-->Ser substitution in the heterozygous state. We expressed in a bacterial system the new aldolase A Gly346-->Ser mutant, and the Glu206-->Lys mutant identified by others, in a patient with an aldolase A deficit. Analysis of their functional profiles showed that the Gly346Ser mutant had the same Km as the wild-type enzyme, but a 4-fold lower kcat. The Glu206-->Lys mutant had a Km approx. 2-fold higher than that of both the Gly346-->Ser mutant and the wild-type enzyme, and a kcat value 40% less than the wild-type. The Gly346-->Ser and wild-type enzymes had the same Tm (melting temperature), which was approx. 6-7 degrees C higher than that of the Glu206-->Lys enzyme. An extensive molecular graphic analysis of the mutated enzymes, using human and rabbit aldolase A crystallographic structures, suggests that the Glu206-->Lys mutation destabilizes the aldolase A tetramer at the subunit interface, and highlights the fact that the glycine-to-serine substitution at position 346 limits the flexibility of the C-terminal region. These results also provide the first evidence that Gly346 is crucial for the correct conformation and function of aldolase A, because it governs the entry/release of the substrates into/from the enzyme cleft, and/or allows important C-terminal residues to approach the active site.

Congenital fiber type disproportion--30 years on.

Thirty years ago, M. H. Brooke coined the term "congenital fiber type disproportion" (CFTD) to describe 12 children who had clinical features of a congenital myopathy and relative type 1 fiber hypotrophy on muscle biopsy. It is now clear that this histological pattern can accompany a wide range of neurological disorders, leading to disillusionment with CFTD as a distinct nosological entity. To determine whether the CFTD has clinical utility as a diagnostic entity, we have reviewed the literature for cases of type 1 fiber hypotrophy and have used strict exclusion criteria to identify 67 cases of CFTD. Most patients presented at birth with weakness and hypotonia, had normal intelligence, and followed a static or improving clinical course. In 43% of families, more than 1 individual was affected. Failure to thrive was common and 25% of patients had contractures or spinal deformities. Bulbar weakness and ophthalmoplegia were less common and cardiac involvement was rare. Twenty-five percent followed a severe course and 10% had died at the time of reporting, all from respiratory failure. Ophthalmoplegia and facial and bulbar weakness were significantly associated with a poorer prognosis. The relatively homogeneous phenotype supports the retention of CFTD as a distinct diagnostic entity and familial occurrence suggests a genetic basis. Regarding the diagnosis of CFTD, we found no strong evidence that the minimum difference between type 1 and type 2 fiber sizes should be increased from 12% to 25%. We also list the other reported causes of relative type 1 fiber hypotrophy to aid their exclusion from CFTD.

Ullrich disease: collagen VI deficiency: EM suggests a new basis for muscular weakness.

Ullrich disease is a form of congenital muscular dystrophy characterized clinically by generalized muscle weakness, contractures of the proximal joints, and hyperflexibility of the distal joints from birth or early infancy. Recently, mutations of the collagen VI gene have been associated with Ullrich disease. The authors report on a boy with Ullrich disease who has complete deficiency of collagen VI and harbors compound heterozygous mutations in the collagen VI alpha 2 gene. Absence of microfibrils on EM, together with normal collagen fibrils and basal lamina, suggests that loss of a link between interstitium and basal lamina may be a new molecular pathomechanism of muscular dystrophy.

Congenital cervical spinal atrophy: an intrauterine hypoxic insult.

We present two patients with congenital cervical spinal atrophy who were born at 37 and 33 weeks of gestation. Both patients were unrelated and had no family history of neuromuscular diseases. They presented at birth with arthrogryposis multiplex and symmetrical severe muscle weakness and wasting confined to the upper extremities. There was no sensory or bulbar symptom. Electromyography showed polyphasic and fast-firing units in the proximal muscles of the upper extremities. With the evidence of chronic denervation and re-innervation, we speculate that this static condition is most likely due to circulatory insufficiency causing anterior horn cell ischemia during the latter part of the first trimester.

[Respiratory failure during the course of congenital myopathy effectively treated with nocturnal noninvasive nasal positive pressure ventilation]. / Niewydolnosc oddychania w przebiegu wrodzonej miopatii skutecznie leczona nieinwazyjnym wspomaganiem wentylacji.

Respiratory muscle weakness in myopathy may result in respiratory failure. 41 year old male with congenital myopathy was successfully treated with nocturnal noninvasive nasal positive pressure ventilation. NPPV resulted in improvement of arterial blood gases and allowed to close tracheostomy. Patient was able to return to full time employment.

A novel 7.4 kb mitochondrial deletion in a patient with congenital progressive external ophthalmoplegia, muscle weakness and mental retardation.

We present a patient with external ophthalmoplegia, bilateral ptosis, progressive muscle weakness with "ragged-red fibres" and mental retardation. Mitochondrial DNA analysis by Southern blot revealed heteroplasmy in muscle for a 7.4 kb deletion. In white blood cells, the deletion was only detectable by PCR. There was no evidence for duplications, nor for multiple deletions in the proband or siblings. PCR analysis did not reveal the presence of a mitochondrial DNA defect in the parents and siblings. Thus, there is no experimental support for a maternally inherited mitochondrial DNA deletion. We consider this a sporadic case with a de novo deletion. Diabetes and complaints of fatigue, also seen in this family, are probably coincidental. Mental retardation has been reported occasionally in patients with mitochondrial deletions, but is not common.

Bethlem myopathy: a slowly progressive congenital muscular dystrophy with contractures.

Bethlem myopathy is an early-onset benign autosomal dominant myopathy with contractures caused by mutations in collagen type VI genes. It has been reported that onset occurs in early childhood. We investigated the natural course of Bethlem myopathy in five previously published kindreds and two novel pedigrees, with particular attention to the mode of onset in 23 children and the progression of weakness in 36 adult patients. Our analysis shows that nearly all children exhibit weakness or contractures during the first 2 years of life. Early features include diminished foetal movements, neonatal hypotonia and congenital contractures which are of a dynamic nature during childhood. The course of Bethlem myopathy in adult patients is less benign than previously thought. Due to slow but ongoing progression, more than two-thirds of patients over 50 years of age use a wheelchair.

Paternal transmission of congenital myotonic dystrophy.

We report a rare case of paternally transmitted congenital myotonic dystrophy (DM). The proband is a 23 year old, mentally retarded male who suffers severe muscular weakness. He presented with respiratory and feeding difficulties at birth. His two sibs suffer from childhood onset DM. Their late father had the adult type of DM, with onset around 30 years. Only six other cases of paternal transmission of congenital DM have been reported recently. We review the sex related effects on transmission of congenital DM. Decreased fertility of males with adult onset DM and contraction of the repeat upon male transmission contribute to the almost absent occurrence of paternal transmission of congenital DM. Also the fathers of the reported congenitally affected children showed, on average, shorter CTG repeat lengths and hence less severe clinical symptoms than the mothers of children with congenital DM. We conclude that paternal transmission of congenital DM is rare and preferentially occurs with onset of DM past 30 years in the father.