Hereditary neuropathy with liability to pressure palsies in infancy

Hereditary neuropathy with liability to pressure palsies is an autosomal-dominant disorder, classically characterized by recurrent mononeuropathies, associated with a deletion at 17p11.2, encompassing the peripheral myelin protein 22 gene. The typical clinical episodes of pressure palsy are usually noted for the first time during the 2nd or 3rd decade of life. We found only few reports in prepubertal children. We report a case of a 7.5-year-old child with muscle weakness and severe hypotonia associated with developmental gross motor delay. We suspect that bilateral peroneal nerve palsies after birth were the first episode of pressure palsy. Nerve conduction studies demonstrated slightly prolonged distal latencies with normal conduction velocity. Typical features of hereditary neuropathy with liability to pressure palsies with recurrent mononeuropathies were found in the father. DNA analysis revealed 1.5-Mb deletion at 17p11.2 in both father and child. To the best of our knowledge, this patient is one of the youngest ever found with this disease.

The hypotonic infant: case study of central core disease

Causes of hypotonia in the newborn can be broadly categorized into two classifications. Hypotonia with a supraspinal origin may be seen with systemic disease, hypoxic ischemic encephalopathy, cerebral malformations, syndromes (for example: Down, Prader-Willi, Lowe, Zellweger, Smith-Lemli-Opitz), and c-spine injury. Disorders of the motor unit that present with hypotonia in the newborn period include SMA, congenital myotonic dystrophy, congenital myasthenia gravis, and congenital myopathies. Central core disease is one of the classic congenital myopathies that can be differentiated based on characteristic histologic findings. Muscle fiber samples from patients with central core disease possess distinct morphology that can be diagnostic. Many infants may not exhibit muscle weakness in the newborn period, although there have been rare cases of profound hypotonia and respiratory failure. Clearly, muscle biopsy is the gold standard and is indicated for any infant with marked hypotonia that is not thought to be supraspinal in origin.

Osteosclerotic metaphyseal dysplasia: a skeletal dysplasia that may mimic lead poisoning in a child with hypotonia and seizures

We report the case of a 23-month-old male with hypotonia, developmental delay, and complex seizures. Radiographs revealed profound sclerosis of the metaphyses and epiphyses of the long and short bones in the extremities, with a unique pattern of distribution. Sclerosis also involved the anterior ribs, iliac crests, talus, and calcaneus. The skull and vertebral bodies appeared unaffected. Blood lead levels were normal. We believe that this constellation of clinical and radiographic abnormalities closely resembles osteosclerotic metaphyseal dysplasia (OMD) due to an autosomal recessive defect. Characteristic skeletal findings were instrumental in determining the diagnosis. OMD is a very rare sclerosing bone disorder, first described in 1993. The syndrome is characterized clinically by developmental delay of a progressive nature, hypotonia, elevated alkaline phosphatase, and late-onset spastic paraplegia. We encountered a young child with these neurologic symptoms who displayed sclerotic metaphyseal changes on hand radiographs obtained to determine the bone age. Lead poisoning, a known cause of metaphyseal sclerosis, was initially suspected. Careful analysis of the metaphyseal bone changes helped to distinguish this bone dysplasia from lead poisoning and other causes of metaphyseal sclerosis.

Muscle ultrasonography and electromyography correlation for evaluation of floppy infants

Floppiness in an infant may have a number of different etiologies from disorders of the brain to spinal cord lesions, neuropathies, neuromuscular junction disorders and myopathies. In this study we aimed to investigate the correlation of muscle ultrasonography (US) and electromyography (EMG) in the diagnosis of floppy infants. The study encompassed 41 floppy infants aged 2-24 months. The muscle US and EMG examinations were performed without awareness of the clinical diagnosis. The final diagnosis was established by molecular genetic tests or muscle/nerve biopsy. The neurogenic group consisted of 16 infants according to their US and EMG findings. Fifteen of them had spinal muscular atrophy proven by genetic analysis and one had polyneuropathy diagnosed by nerve biopsy. Six infants were in the myopathic group according to their muscle US and EMG results. All of them underwent muscle biopsy and microscopic examination revealed five congenital muscular dystrophy and one glycogen storage disease. In two infants the US and EMG data conflicted. Their biopsies were also insufficient for the diagnosis. Seventeen infants had normal US and EMG findings but pathologic cranial magnetic resonance imaging or metabolic/genetic tests. They were considered in the group of central hypotonia. Our results suggest a high concordance of US and EMG findings in the diagnostic work-up of neurogenic and myopathic disorders.

Muscle power development in preterm infants with periventricular flaring or leukomalacia in relation to outcome at 18 months

Periventricular flaring (PVF) or periventricular leukomalacia (PVL) was diagnosed by brain ultrasound during the neonatal period in 44 infants (34 males, 10 females; mean gestational age 31 weeks 2 days, SD 2 weeks 1 day) admitted between 1995 and 1997. The infants were divided into three groups according to the severity of their condition. At 0, 3, and 6 months' corrected age an age-adequate neurological examination with special emphasis on the relation between active and passive muscle power was performed and symmetry between right and left sides was assessed. Results for the whole body, as well as for the shoulders, trunk, and legs were classified as optimal, suspect, or abnormal. Motor outcome at 18 months' corrected age was graded in the same way. An overall optimal muscle power regulation was found in one infant at 0, two at 3, and one at 6 months. Suspect outcome was found at all ages in the three groups. At 0 months muscle power regulation did not differ between the three groups. At 3 and 6 months overall poor muscle power, primarily caused by poor muscle power regulation in the shoulders and trunk, was found in infants with PVL grades III or IV. At 18 months' corrected age 24 infants showed no neurological impairment, eight infants had minor impairment, and 12 infants had severe impairment, including all 10 infants categorized as having PVL grades II or IV. The best predictors of impairment at 18 months were the combined results of muscle power in the shoulders and trunk at 3 months with those of the shoulders at 6 months.

Myogenic failure in posterior urethral valve disease: real or imagined?

PURPOSE

It has been suggested that hypocontractility or myogenic failure develops in older boys with a history of 9 posterior urethral valved as the hyperactive, poorly compliant bladders decompensate with age. Also a much higher prevalence of myogenic failure has been reported than we have observed. We determine the prevalence of myogenic failure in boys with a posterior urethral valve and whether myogenic failure was a consequence of earlier detrusor instability or diminished compliance.

MATERIALS AND METHODS

We retrospectively reviewed the urodynamic findings of 51 boys after transurethral ablation of a posterior urethral valve. Group 1 (longitudinal group) consisted of 11 boys 12 to 19 years old who had undergone at least 1 serial urodynamic study before and 1 after age 10 years. Group 2 (younger group) included 33 boys whose urodynamic testing was performed before age 10 years. Group 3 (older group) comprised 7 previously treated boys whose initial urodynamic study was done after age 12 years.

RESULTS

Overall, myogenic failure was noted in 3 (all group 1) of 51 (5.9%) patients. Each of the 3 boys initially had a hypocompliant bladder, and myogenic failure developed only after institution of anticholinergic therapy and resolved once anticholinergics were discontinued. An additional 34 boys treated with anticholinergics did not have myogenic failure. No tendency towards myogenic failure or marked increase in bladder capacity for age was noted in the older boys.

CONCLUSIONS

In our experience myogenic failure is uncommon and more likely secondary to anticholinergic therapy than a preordained consequence of valve disease. We postulate that our proactive, early aggressive use of urodynamic studies and pharmacotherapy to identify and manage the secondary effects of valve disease reduces the incidence of myogenic failure.

Hypotonic-hyporesponsive episodes following pertussis vaccination: a cause for concern?

Vaccine safety has become a major community concern and of particular importance for parents, vaccine recipients and vaccine providers. A hypotonic-hyporesponsive episode (HHE) is a sudden and unexpected episode of loss of tone, unresponsiveness and colour change which uncommonly affects infants and children after vaccination. Although any vaccine may be associated with this adverse event, HHE usually follows administration of a pertussis containing vaccine. There has been renewed interest in this adverse event in the light of community concerns regarding vaccine safety. The focus of this interest has been to formulate an acceptable case definition, to document possible risk factors and to better define the outcome of HHE. In addition, studies have documented the outcome of revaccination of children who have had an HHE. Although much remains to be learnt about HHE it would appear that there are no long-term sequelae and that children who have had an HHE can be revaccinated. Parents should be provided with the available information such that they can make an assessment of the risks and benefits of pertussis vaccination. The benefits of pertussis vaccination still outweigh the risk and universal childhood pertussis vaccination should continue to be advocated.

Congenital hypotonia with favorable outcome

Congenital hypotonia with favorable outcome is characterized by an early neonatal onset and a benign clinical course. The old term, proposed by Walton, was benign congenital hypotonia, denoting the presence of muscle weakness and hypotonia, with the exception of Werdnig-Hoffmann disease. It has been clear that this term includes congenital myopathies with definite changes in the muscle fiber. However, many cases remain unclarified. The term congenital hypotonia with favorable outcome includes only these last cases. A long-term follow-up study of children with congenital hypotonia with favorable outcome is presented, and a hypothetical mechanism underlying muscle shortening is discussed. The study was carried out at the Department of Child Neuropsychiatric Sciences, University "La Sapienza" of Rome, during the period 1985-2000, and included 41 patients with congenital hypotonia. Our study confirms the good prognosis of congenital hypotonia with favorable outcome and suggests a correlation with joint hyperlaxity, which is observed in many parents of our children, as if the latter developed from the former. On the basis of experimental changes occurring in the muscles, we believe that in our cohort the main cause of shortening is caused by an increase in joint mobility, which keeps muscles shortened in both the passive and active states for a long time. If this view is confirmed by other studies, we suggest continuous muscle exercise as a preventive treatment.

Rett syndrome: clinical manifestations in males with MECP2 mutations

Rett syndrome is a neurodevelopmental disorder characterized by cognitive and adaptive regression with autistic features, loss of acquired skills, and stereotypic hand movements that almost exclusively affects females. It is an X-linked dominant disorder, with presumed lethality in males. Nonetheless, there are a few descriptions of males suspected of having Rett syndrome. With the recent discovery that the MECP2 gene is responsible for most cases of Rett syndrome, it is possible to molecularly assess cases of affected males by direct sequencing analysis. We describe an Israeli family consisting of a female having classic Rett syndrome and a male sibling with severe neonatal encephalopathy. Molecular analysis revealed that both sister and brother have the same MECP2 gene mutation; however, their mother does not. This case, as well as other published studies of males with MECP2 mutations, reveals that the clinical manifestations in viable males vary from neonates with severe encephalopathy to adults with mental retardation and demonstrate genotype-phenotype correlations.

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.

Myelitis and ascending flaccid paralysis due to congenital toxoplasmosis

A 4-week-old female newborn developed ascending flaccid paralysis and radiologic evidence of myelitis; the diagnosis of congenital toxoplasmosis was confirmed by the presence of Toxoplasma gondii-specific immunoglobulins in both mother and infant, and detection of Toxoplasma sequences in the infant's cerebrospinal fluid by polymerase chain reaction analysis. Treatment with pyrimethamine, sulfadiazine, and methylprednisolone resulted in improvement.

Spectrum of floppy children in Indian scenario

OBJECTIVE

To study the clinical profile of paralytic floppy infants undertaking available investigations and detect the frequency of exon7 of survival motor neuron (SMNT) gene deletion among the spinal muscular atrophy (SMA) cases.

DESIGN

Descriptive study.

SETTING

Tertiary care teaching hospital.

SUBJECTS

70 paralytic floppy infants (40 males/30 females) with age less than 13 years were included in the study. Exclusion criteria included central hypotonia of any cause. Detailed clinical evaluation was done followed by serum creatine phosphokinase levels, electrophysiological studies, muscle biopsy including immunohistochemistry and electron microscopy. Exon7 of SMNT gene deletion studies was done by PCR.

RESULTS

Final diagnosis of SMA was assigned to 37 patients followed by congenital myopathy (n = 7), cogenital muscular dystrophy (n = 5), mitochondrial myopathy (n = 4), neuropathies (n = 5) and diaphragmatic SMA (n = 1). Only 15.7% of cases remained unclassified. When EMG was correlated with final diagnosis, it was 80.6% and 75% sensitive and 68.8% and 87.5% specific for neurogenic and muscle disease, respectively. Muscle biopsy revealed neurogenic atrophy in 47.8% cases followed by normal in 37.3% and myopathic pattern in 14.97% cases. Exon7 of SMNT gene was deleted in only 50% of SMA cases.

CONCLUSIONS

Spinal muscular atrophy was the commonest cause of floppy children. The low rate of SMNT gene deletion detected needs confirmation with further studies.

Quantitative assessment of brainstem development in Joubert syndrome and Dandy-Walker syndrome

Key features of Joubert syndrome include developmental delay, hypotonia, hyperpnea and apnea, oculomotor apraxia, and the presence of the molar tooth sign on axial imaging through the brainstem isthmus--the junction of the pons and mesencephalon. Interestingly, 1 in 10 patients with Joubert syndrome has abnormal cerebrospinal fluid collections misdiagnosed as Dandy-Walker variants. Because of important differences in patient management, genetic counseling, and prognosis between these conditions, we undertook a study to determine if the brainstem isthmus is normal in Dandy-Walker syndrome. Using standard landmarks, we evaluated development of the isthmus in normal subjects and in subjects with Joubert syndrome and Dandy-Walker syndrome. Four of five brainstem measures increased with age in normal subjects. In subjects with Joubert syndrome, the depth and length of the interpeduncular fossa were increased, and the width of the isthmus was decreased. In subjects with Dandy-Walker syndrome, the width of the brainstem isthmus was normal, and the molar tooth sign was absent. Although the pons can be hypoplastic in Dandy-Walker syndrome, we conclude that the pontomesencephalic junction is normal. Thus, the molar tooth sign can effectively distinguish between Joubert and Dandy-Walker syndromes. Genetic heterogeneity or epigenetic factors may account for abnormal cerebrospinal fluid collections in some cases of Joubert syndrome.

Atypical presentation of dopa-responsive dystonia: generalized hypotonia and proximal weakness

Dopa-responsive dystonia (DRD) is an autosomal dominant disorder typically presenting as dystonia with diurnal variability. Described is an 8-year-old boy who had had waddling gait, generalized hypotonia, and proximal weakness since early childhood. He responded well to low-dose L-dopa. He had a point mutation of the GTP cyclohydrolase I gene. The patient's father and sister had the same mutation but did not have proximal weakness. GTP cyclohydrolase I deficiency can present with hypotonia and weakness.

Clinical correlates of white-matter abnormalities on head magnetic resonance imaging

We undertook this study to investigate the relationship between white-matter abnormalities (seen on brain magnetic resonance imaging [MRI]) and muscle tone and muscle stretch reflexes on clinical examination. We identified all patients less than 5 years of age who had undergone cranial MRI studies at Riley Hospital for Children between June 30, 1999, and July 1, 2000, whose scans were read as showing white-matter abnormalities. We measured two ratios and the thickness of the corpus callosum as indicators of the quantity of cerebral white matter. The ratios were R1, the ratio of the thickness of the white matter at the level just above the body of the lateral ventricle compared with the width of the hemisphere, and R2, the ratio of the thickness of the white matter to the width of the hemisphere at the level of the trigone of the lateral ventricle. The thickness of the corpus callosum was measured at the junction of the anterior two thirds and the posterior third. We also evaluated the signal intensity of the cerebral white matter by reviewing the fluid-attenuated inversion-recovery images and grading the signal as normal to severely abnormal depending on the degree and extent of high signal intensity seen (0 = normal to 4+). Thirty-eight children less than 5 years of age who underwent MRI scans between June and August 2000 and who were found to have normal tone prospectively and normal MRI scan on review served as a control group. We identified 215 patients who had white-matter abnormalities; of these, only 142 (66%) had documented tone assessments in their medical record. Our study group was divided into three groups: increased (n = 35), decreased (n = 53), and normal tone (n = 54). All three measurements of white matter in each of the three study groups were significantly below values for control children. The children with white-matter abnormalities and decreased tone had significantly less signal intensity abnormality than the other study groups. Children with white-matter abnormalities and increased tone had a greater frequency of increased reflexes and tended to have more signal abnormalities than the other groups. The group of children with white-matter abnormalities and normal tone had the least amount of cerebral white-matter deficiency of the three study groups. In patients with strikingly decreased quantities of cerebral white matter, those with normal signal-intensity white matter are likely to be hypotonic with normal reflexes and those with increased signal intensity in the white matter are likely to be spastic.

Carnitine-deficient myopathy as a presentation of tyrosinemia type I

Carnitine deficiency secondary to renal Fanconi's tubulopathy has been described in only a few inborn errors of metabolism: cystinosis, galactosemia, and Fanconi-Bieckel syndrome. We report a 27-month-old infant who presented with a sudden change in gait owing to proximal muscle weakness. The laboratory evaluation showed carnitine deficiency associated with Fanconi's tubulopathy. Eventually, tyrosinemia type I was diagnosed. Carnitine deficiency can contribute to the clinical picture of hepatorenal tyrosinemia and should therefore be evaluated and treated.

Focusing on dissociated motor development in Brazilian children

Dissociated motor development (DMD) is considered when the baby starts independent walking late, with normality of the other fields of development. There is evidence that babies with DMD present an atypical crawling pattern and hypotonia. To investigate the frequency and characteristics of DMD, neurological examination was performed monthly in 177 healthy full-term babies from 6 months age, in urban and rural zone samples in Brazil. Among 20 children with atypical crawling, none presented hypotonia neither did they start independent walking late. The means of the ages at the beginning of atypical crawling and independent walking acquisitions, 7.40 mo (SD 1.4) and 12.76 mo (SD 2.5) respectively, did not differ from the group with crossed crawling pattern. Thus, in this sample of Brazilian healthy children we did not find cases with DMD.

Analysis of ankle kinetics during walking in individuals with Down syndrome

The biomechanical characteristics of the ankle during gait of 17 participants with Down syndrome, ages 8 to 36 years, were investigated. Ten volunteers without disabilities of comparable anthropometric parameters were the control group. A 3-dimensional gait analysis was performed using an optoelectronic system equipped with a force platform. Participants with Down syndrome showed significant decreases of plantar-flexor moments and of A1 and A2 joint powers. Furthermore, correlation between kinetic and temporal spatial parameters was markedly reduced or weak in comparison to the control group. These results point out a hypofunctioning of ankle, probably due to hypotonia and ligament laxity.

Leigh disease: clinical, neuroradiologic, and biochemical study of three new cases with cytochrome c oxidase deficiency

Three cases of Leigh disease are described. In all three, symptoms began in the first months of life, with muscle hypotonia, lactic acidosis, and psychomotor delay. The diagnosis was made on the basis of the clinical characteristics, biochemical abnormalities, and typical brain magnetic resonance imaging with symmetric lesions suggesting bilateral necrosis at the level of the basal ganglia and of the midbrain. Cytochrome c oxidase (complex IV of the mitochondrial respiratory chain) deficiency was demonstrated in muscle tissue in all patients and confirmed in skin fibroblasts in patient 3. A genetic heterogeneity was present in these patients since only one had a SURF-1 gene mutation. The clinical, biochemical, and neuroradiologic aspects are discussed. Finally, the finding of facial dysmorphisms in the cytochrome c oxidase deficiency observed in one of the described cases is of extreme interest; to our knowledge, this association has never been reported in the literature.

[Neonatal hypotonia of muscular origin: analysis of 50 cases]

BACKGROUND

Neonatal hypotonia is a common request for neurological consultation. The aim of this study is to describe the main clinical features of muscular hypotonia in newborns at the light of the histopathological findings.

METHODS

We reviewed 50 medical records of hypotonic neonates with abnormal muscular biopsy. In all of the cases, the serum concentration of creatine kinase was determined and biopsies were examined by a qualified neuropathologist.

RESULTS

The most frequent muscular cause of neonatal hypotonia was specific congenital myopathies (23 cases), followed by congenital muscular dystrophy (15 cases), congenital myotonic dystrophy (eight cases) and metabolic myopathies (four cases). The most common specific congenital myopathy was fiber type disproportion (10 cases). The association with joint contractures and the involvement of respiratory muscles were frequent; respiratory complications were the first cause of death.

CONCLUSIONS

Muscular biopsy is required for the definitive diagnosis of specific congenital myopathies, congenital muscular dystrophy and metabolic myopathies. In congenital myotonic dystrophy, the mother is almost always affected; neonates with specific congenital myopathies and congenital muscular dystrophy can be very similar to those with congenital myotonic dystrophy; the examination of the mother, specially a careful search for myotonia, is the best diagnostic clue; if there are signs of myotonia, the diagnosis can be made by molecular genetic study.

Toriello-Carey syndrome: an additional case and summary of previously reported cases

We report an additional case of Toriello-Carey syndrome, a rare multiple malformation syndrome, and present a summary of previously reported cases.

Marden-Walker syndrome: case report, nosologic discussion and aspects of counseling

The Marden-Walker syndrome is characterized by a mask-like face with blepharophimosis, micrognathia, cleft or high-arched palate, low-set ears, congenital joint contractures, decreased muscular mass, failure to thrive and psychomotor retardation. We report a boy with a phenotype mostly resembling the condition named Marden-Walker syndrome, with many of the criteria proposed for diagnosing this particular phenotype. In addition he had hypoplastic corpus callosum, cerebellar vermis hypoplasia, enlarged cisterna magna and vertebral abnormalities. During pregnancy there were reduced fetal movements. In the present patient the fetal hypokinesia sequence, due to central nervous system malformation, is most compatible with the diagnosis of Marden-Walker syndrome. The etiology is probably heterogeneous, but the possibility of autosomal recessive inheritance should be considered in genetic counseling.

Relationships among three clinical measures of muscle tone at the elbows of individuals after a stroke

Patterns of associations among three common clinical muscle tone measures were investigated to determine their degree, and patterns of agreement. Data contributing to selection of clinical measures of muscle tone and understanding factors contributing to occupational dysfunctions were also sought. Forty five persons who were admitted after stroke to two occupational therapy rehabilitation programs were randomly selected. Their affected elbow's resting position (EJP), resistance to passive extension (ERM) and the angle where resistance first appeared (EAR) were measured by one, then a second therapist who also measured voluntary muscle function. Correlations among the three measures were calculated for both administrations and among patient subgroups with statistical correction for multiple correlations. Statistically significant associations appeared between ERM and EAR and between EJP and EAR. Highest statistically significant associations appeared among subjects with poor upper extremity function and those with low muscle tone. Patterns of associations were similar for the first and second administrations at both centres, though patterns among subgroups differed between centres. Correlation patterns suggest that biomechanical factors may influence the joint's resting position (EJP) more than ERM and EAR. Measures may be used interchangeably only with selected patient subgroups, which should also be the basis of method selection.