Preliminary insights into RNA in CSF of pediatric SMA patients after 6 months of nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a rare autosomal-recessive neurodegenerative disorder caused by mutations in survival motor neuron 1 (SMN1) gene, and consequent loss of function of SMN protein, which results in progressive loss of lower motor neurons, and muscular wasting. Antisense oligonucleotide (ASO) nusinersen (Spinraza®) modulates the pre-mRNA splicing of the SMN2 gene, allowing rebalance of biologically active SMN. It is administered intrathecally via lumbar puncture after removing an equal amount of cerebrospinal fluid (CSF). Its effect was proven beneficial and approved since 2017 for SMA treatment. Given the direct effect of nusinersen on RNA metabolism, the aim of this project was to evaluate cell-free RNA (cfRNA) in CSF of SMA patients under ASOs treatment for biomarker discovery.

METHODS

By RNA-sequencing approach, RNA obtained from CSF of pediatric SMA type 2 and 3 patients was processed after 6 months of nusinersen treatment, at fifth intrathecal injection (T6), and compared to baseline (T0).

RESULTS

We observed the deregulation of cfRNAs in patients at T6 and we were able to classify these RNAs into disease specific, treatment specific and treatment dependent. Moreover, we subdivided patients into "homogeneous" and "heterogeneous" according to their gene expression pattern. The "heterogeneous" group showed peculiar activation of genes coding for ribosomal components, meaning that in these patients a different molecular effect of nusinersen is observable, even if this specific molecular response was not referable to a clinical pattern.

CONCLUSIONS

This study provides preliminary insights into modulation of gene expression dependent on nusinersen treatment and lays the foundation for biomarkers discovery.

Effects of genotype and age on eggshell cuticle coverage and color profile in modern laying hen strains

The aim of this research was to investigate the effects of laying hen genotype and age on eggshell cuticle deposition. A total of 4,320 brown eggs were obtained from 3 modern hen strains (A, B, and C), currently used worldwide for commercial egg production, at different intervals of age (20–30, 40–50, and 60–70 wk). Four samplings of 120 randomly collected eggs were carried out for each genotype/interval of age. Eggs were individually weighed and cuticle blue staining was used to assess quality and degree of cuticle coverage. On each egg, the eggshell color profile was assessed before and after staining using the CIE L*a*b* system and these values were used to calculate ΔE*_ab. A 4-point scale visual score (VS) system was also applied to estimate the degree of cuticle coverage after staining (0 = no coverage, 1 = partial coverage, 2 = total coverage - low degree, 3 = total coverage - high degree). The effects of genotype and age and their interaction on eggshell color attributes were assessed by means of factorial ANOVA, while omnibus Chi-Square and Chi-squared Automatic Interaction Detector algorithm were applied for the analysis of VS data. Overall, both genotype and age affected the eggshell color profile as well as the degree of cuticle coverage. Hen strain A showed better cuticle deposition in comparison with B and particularly C one, being ΔE*_ab values significantly higher. The VS evaluation revealed that eggs with impaired cuticle coverage degree increased with the hen age (23, 34, and 37%, respectively for 20–30, 40–50, and 60–70 wk; P < 0.05). However, a significant interaction between genotype and age was observed: transition from early to late hen age resulted in a significantly different pattern of ΔE*_ab changes in each genotype. The classification tree analysis confirmed that the hen genotype has a greater effect than the age on cuticle deposition. In conclusion, considering the importance of the cuticle in table egg production, these results highlight the crucial role exerted by the genotype on eggshell cuticle coverage.

Respiratory and cardiac function in congenital muscular dystrophies with alpha dystroglycan deficiency

The aim of this retrospective study was to assess respiratory and cardiac function in a large cohort of patients with congenital muscular dystrophies (CMD) with reduced glycosylation of alphadystroglycan (α-DG). Thirteen of the 115 patients included in the study died between the age of 1 month and 20 years. The age at last follow up of the surviving 102 ranged between 1 year and 68 years (median: 9.3 years). Cardiac involvement was found in 7 of the 115 (6%), 5 with dilated cardiomyopathy, 1 cardiac conductions defects and 1 mitral regurgitation. Respiratory function was impaired in 14 (12%). Ten of the 14 required non invasive nocturnal respiratory support, while the other four required invasive ventilation. Cardiac or respiratory involvement was found in patients with mutations in FKRP, POMT1, POMT2. All of the patients in whom mutation in POMGnT1 were identified had normal cardiac and respiratory function.

Congenital muscular dystrophies with cognitive impairment. A population study

BACKGROUND

Cognitive impairment has been reported in a significant proportion of patients with congenital muscular dystrophies (CMD), generally associated with brain changes.

OBJECTIVES

The aim of this study was to establish 1) the overall prevalence of CMD and cognitive impairment in the Italian population; 2) the frequency of individual genetically defined forms; and 3) the presence of distinct phenotypes not associated with mutations in the known genes.

METHODS

We included all patients with CMD and cognitive impairment followed in all the Italian tertiary neuromuscular centers. Clinical, brain MRI, and morphologic data were collected. Genetic screening of the known genes was performed according to clinical and muscle biopsy findings.

RESULTS

Ninety-two of the 160 (58%) patients with CMD followed in our centers had cognitive impairment. alpha-Dystroglycan (alpha-DG) reduction on muscle biopsy was found in 73/92 (79%), with 42/73 carrying mutations in the known genes. Another 6/92 (7%) showed a laminin alpha2 deficiency on muscle biopsy and 5 of the 6 carried mutations in LAMA2. The remaining 13/92 (14%) patients had normal alpha-DG and laminin alpha2 expression on muscle.

CONCLUSIONS

This is the first population study establishing the prevalence of CMD and cognitive impairment and providing a classification on the basis of clinical, MRI, and genetic findings. We also showed that cognitive impairment was not always associated with alpha-DG or laminin alpha2 reduction or with structural brain changes.

Reliability of the North Star Ambulatory Assessment in a multicentric setting

The aim of this study was to investigate the suitability of the North Star Ambulatory Assessment as a possible outcome measure in multicentric clinical trials. More specifically we wished to investigate the level of training needed for achieving a good interobserver reliability in a multicentric setting. The scale was specifically designed for ambulant children with Duchenne Muscular Dystrophy and includes 17 items that are relevant for this cohort. Thirteen Italian centers participated in the study. In the first phase of the study we provided two training videos and an example of the scale performed on a child. After the first session of training, all the 13 examiners were asked to send a video with an assessment performed in their centre and to score all the videos collected. There were no difficulties in performing the items and in obtaining adequate videos with a hand held camera but the results showed a poor interobserver reliability (<.5). After a second training session with review and discussion of the videos previously scored, the same examiners were asked to score three new videos. The results of this session had an excellent interobserver reliability (.995). The level of agreement was maintained even when the same videos were rescored after a month, showing a significant intra-observer reliability (.95). Our results suggest that the NSAA is a test that can be easily performed, completed in 10 min and can be used in a multicentric setting, providing that adequate training is administered.

Congenital muscular dystrophies with defective glycosylation of dystroglycan: a population study

BACKGROUND

Congenital muscular dystrophies (CMD) with reduced glycosylation of alpha-dystroglycan (alpha-DG) are a heterogeneous group of conditions associated with mutations in six genes encoding proven or putative glycosyltransferases.

OBJECTIVES

The aim of the study was to establish the prevalence of mutations in the six genes in the Italian population and the spectrum of clinical and brain MRI findings.

METHODS

As part of a multicentric study involving all the tertiary neuromuscular centers in Italy, FKRP, POMT1, POMT2, POMGnT1, fukutin, and LARGE were screened in 81 patients with CMD and alpha-DG reduction on muscle biopsy (n = 76) or with a phenotype suggestive of alpha-dystroglycanopathy but in whom a muscle biopsy was not available for alpha-DG immunostaining (n = 5).

RESULTS

Homozygous and compound heterozygous mutations were detected in a total of 43/81 patients (53%), and included seven novel variants. Mutations in POMT1 were the most prevalent in our cohort (21%), followed by POMT2 (11%), POMGnT1 (10%), and FKRP (9%). One patient carried two heterozygous mutations in fukutin and one case harbored a new homozygous variant in LARGE. No clear-cut genotype-phenotype correlation could be observed with each gene, resulting in a wide spectrum of clinical phenotypes. The more severe phenotypes, however, appeared to be consistently associated with mutations predicted to result in a severe disruption of the respective genes.

CONCLUSIONS

Our data broaden the clinical spectrum associated with mutations in glycosyltransferases and provide data on their prevalence in the Italian population.

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.

Phenotypic clustering of lamin A/C mutations in neuromuscular patients

BACKGROUND

Mutations in the LMNA gene, encoding human lamin A/C, have been associated with an increasing number of disorders often involving skeletal and cardiac muscle, but no clear genotype/phenotype correlation could be established to date.

METHODS

We analyzed the LMNA gene in a large cohort of patients mainly affected by neuromuscular or cardiac disease and clustered mutated patients in two groups to unravel possible correlations.

RESULTS

We identified 28 variants, 9 of which reported for the first time. The two groups of patients were characterized by clinical and genetic differences: 1) patients with childhood onset displayed skeletal muscle involvement with predominant scapuloperoneal and facial weakness associated with missense mutations; 2) patients with adult onset mainly showed cardiac disorders or myopathy with limb girdle distribution, often associated with frameshift mutations presumably leading to a truncated protein.

CONCLUSIONS

Our findings, supported by meta-analysis of previous literature, suggest the presence of two different pathogenetic mechanisms: late onset phenotypes may arise through loss of function secondary to haploinsufficiency, while dominant negative or toxic gain of function mechanisms may explain the severity of early phenotypes. This model of patient stratification may help patient management and facilitate future studies aimed at deciphering lamin A/C pathogenesis.

Randomized, double-blind, placebo-controlled trial of phenylbutyrate in spinal muscular atrophy

OBJECTIVE

To assess the efficacy of phenylbutyrate (PB) in patients with spinal muscular atrophy in a randomized, double-blind, placebo-controlled trial involving 10 Italian centers.

METHODS

One hundred seven children were assigned to receive PB (500 mg/kg/day) or matching placebo on an intermittent regimen (7 days on/7 days off) for 13 weeks. The Hammersmith functional motor scale (primary outcome measure), myometry, and forced vital capacity were assessed at baseline and at weeks 5 and 13.

RESULTS

Between January and September 2004, 107 patients aged 30 to 154 months were enrolled. PB was well tolerated, with only one child withdrawing because of adverse events. Mean improvement in functional score was 0.60 in the PB arm and 0.73 in placebo arm (p = 0.70). Changes in the secondary endpoints were also similar in the two study arms.

CONCLUSIONS

Phenylbutyrate was not effective at the regimen, schedule, and duration used in this study.

POMT2 mutation in a patient with 'MEB-like' phenotype

Mutations in POMT2 have so far only been reported in patients with Walker-Warburg phenotype. We report heterozygous POMT2 mutations in an a girl with a milder phenotype characterized by mental retardation, microcephaly, hypertrophy of the quadriceps and calf muscles, and structural brain changes mostly affecting the posterior fossa. Our findings suggest that, as previously reported for POMT1 and FKRP, mutations in the POMT2 can also be associated with clinical heterogeneity.

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.

LAMA2loss-of-function mutation in a girl with a mild congenital muscular dystrophy

The authors report a girl with autosomal recessive congenital muscular dystrophy linked to chromosome 6 (MDC1A) who carries a homozygous out-of-frame deletion in exon 56 of the LAMA2 gene but has a mild phenotype. She is still ambulant at age 13 years, shows white matter abnormalities on MRI, and traces of laminin alpha2 in her muscle biopsy with one of three antibodies used. This patient suggests that modulating factors can be associated with a less severe clinical phenotype in MDC1A.

Measurement of skeletal muscle mass in Duchenne muscular dystrophy: use of 24-h creatinine excretion

Creatinine concentration in 24-h urine has been proposed as an indirect measure of body skeletal muscle mass (SMM). We attempted to correlate urinary creatinine levels with SMM in eight patients with Duchenne muscular dystrophy, a progressive disease in which the degree of muscle wasting parallels the rate of progression. Magnetic resonance imaging and a newly developed protocol for image analysis were used for the measurement of SMM. The patients ate a creatine-free diet for the week before urine collection. Creatinine was measured with an enzymatic-colorimetric method. Mean (+/-SD) SMM value was 5.4+/-2.5 kg and urine creatinine levels 205.8+/-96.4 mg/day. Daily urinary creatinine excretion did not correlate with SMM. The simple creatinine determination in urine cannot predict SMM in Duchenne muscular dystrophy.

Body composition and energy expenditure in Duchenne muscular dystrophy

OBJECTIVE

To investigate the relationship between resting energy expenditure (REE) and body composition in Duchenne Muscular Dystrophy (DMD).

DESIGN

An observational study.

SETTING

University Research Centre.

SUBJECTS

Nine Duchenne children (age range 6-12 y), mean relative weight 128%, agreed to undergo the investigation and all of them completed the study;

INTERVENTIONS

Assessment of body composition (total body fat and skeletal muscle mass) by magnetic resonance imaging and resting energy expenditure by indirect calorimetry.

MAIN OUTCOME MEASURES

Fat mass (FM; kg and percentage weight), fat-free mass (FFM; kg and percentage weight), muscle mass (kg and percentage weight), resting energy expenditure (kJ/kg body weight and kJ/kg fat-free mass).

RESULTS

: In Duchenne children fat mass averages 32% and total skeletal muscle mass 20% of body weight. Resting energy expenditure per kg of body weight falls within the normal range for children of the same age range, while when expressed per kg of FFM is significantly higher than reference values. No relationship was found between REE and total skeletal muscle mass.

CONCLUSIONS

Our results do not demonstrate a low REE in DMD boys; on the contrary REE per kg of FFM is higher than normal, probably due to the altered FFM composition. We suggest that the development of obesity in DMD children is not primarily due to a low REE but to other causes such as a reduction in physical activity and or overfeeding.

Pelizaeus-Merzbacher disease: electrophysiological study of two sibs with the classic form and of their relatives

We examined two sibs with the classic form of Pelizaeus-Merzbacher disease (PMD) and their relatives. Electromyographic-electroneurographic studies and magnetic stimulation of motor pathways were performed. In both patients we found an absence of compound motor action potential (cMAP) after stimulation of the motor cortex and a normal conduction time by stimulating the cervical roots. Despite reported sparing of the peripheral nervous system in PMD, our conduction study of the tibial nerve revealed a slightly decreased motor nerve conduction velocity in one patient. In both patients the EMG study showed neurogenic findings. The elder sister showed a prolonged central motor conduction time. This study demonstrates abnormalities of motor corticospinal pathways also in PMD relatives suggesting that magnetic stimulation could be useful in detecting "subclinical" abnormalities in this dysmyelinating condition. Furthermore, in accordance with previous studies, we suggest that a slight involvement of the peripheral nervous system could be observed in PMD.

A multicenter, double-blind, randomized trial of deflazacort versus prednisone in Duchenne muscular dystrophy

We randomized 18 Duchenne muscular dystrophy (DMD) boys whose age ranged from 5.2 to 14.6 years (mean, 7.3 years) for treatment with either deflazacort (0.9 mg/kg/day) or prednisone (0.75 mg/kg/day) on the basis of age and functional score at the onset of treatment. We followed the patients every 3 months for 1 year, evaluating four limb muscles with the Medical Research Council scale and performance of four functions (walking, climbing stairs, Gowers' maneuver, and rising from a chair). Side effects were monitored by a questionnaire and by routine blood examination, and weight and height were recorded at each visit. At 12 months, the effect of both steroids was examined by comparing the status of the treated patients with another group of untreated DMD patients that served as natural history control. The two steroids were equally effective in improving motor function and functional performances. At 9 months, the average weight increase with respect to baseline value was 5% (2 kg) in the deflazacort group but 18% in the prednisone group (P < 0. 005), and the change remained significant after 12 months (P < 0.05). Other minor but nonsignificant side effects were observed. Steroid treatment with deflazacort appears to cause fewer side effects than with prednisone, particularly weight gain, which could be important to maximize motor performances.

Heart involvement in muscular dystrophies due to sarcoglycan gene mutations

Mutations in the sarcoglycan genes cause autosomal-recessive muscular dystrophies. Because sarcoglycan genes and their protein products are highly expressed both in skeletal and cardiac muscle, patients with these mutations might be expected to be at risk to develop dilated cardiomyopathy. We therefore studied 13 patients with alpha-, beta-, gamma-sarcoglycan gene mutations by thorough cardiological assessment. Electrocardiographic or echocardiographic abnormalities were observed in about 30% of cases showing a severe course of muscular dystrophy. No correlation was found between the presence of cardiac abnormalities and the type of mutation or sarcoglycan gene involved. The cardiac involvement was never severe, but it may be detected in early stages of the muscle disease. The absence of overt cardiac dysfunction may be due to lower sarcoglycan protein expression in cardiac than skeletal muscle or to less sarcolemmal instability at the myocardial level, possibly related to the different distribution of forces generated by contraction of the myocardium with respect to proximal limb-girdle muscles.

Dolicho-vertebrobasilar abnormality and migraine-like attacks

This is a study of two children with neuroradiologically diagnosed dolichobasilar anomaly: in both cases, the diagnosis was based on magnetic resonance imaging and magnetic resonance angiography findings. We examined the first child (R., aged 6 years and 8 months) following four episodes of intense pain in the left orbit, lasting between 10 and 30 min and accompanied by photophobia and vomiting. The second child (S., aged 9 years and 2 months), suffering from Marfan's syndrome, was examined following recurrent episodes of intense pain that started above the left orbit, moving to the homolateral orbit after a few minutes. These episodes, which lasted between 20 and 30 min, took place mainly at night and were accompanied by phono-photophobia and vomiting. In both cases, the pain attacks can be interpreted as a result of compression of the root of the trigeminal nerve caused by an arterial malformation.

The efficacy of noninvasive mechanical ventilation on nocturnal hypoxaemia in Duchenne's muscular dystrophy

The aim of this 2 yr follow-up study was to evaluate the efficacy of nocturnal noninvasive mechanical ventilation in a group of 10 Duchenne's muscular dystrophy (DMD) patients who desaturated during the night but had normal daytime blood gases: mean (range) age 18.3 (15-22) yrs; mean (SD) vital capacity (VC) 752.5 (460-1,308) mL; mean time in bed (TIB) with arterial oxygen saturation (Sa,O2) < 90% 22.8% of total TIB (range: 16.6-32.0); mean arterial oxygen tension (Pa,O2) 10.3 (9.3-11.7) kPa (78 (70.0-87.8) mmHg); mean arterial carbon dioxide tension (Pa,CO2) 5.9 (4.8-6.5) kPa (44.3 (36.3-48.5) mmHg). All the patients were noninvasively ventilated during the night with a bilevel positive pressure ventilation (BiPAP) devise in spontaneous mode in order to correct the episodes of nocturnal desaturation. Nocturnal Sa,O2 values normalized during nocturnal noninvasive mechanical ventilation, and daytime sleep-disordered breathing disappeared, for the entire study period. No statistically significant differences were observed between baseline and follow-up daytime blood gas values, although a slight increase in Pa,O2 was found. During the follow-up, VC declined at a rate of 79.1 +/- 25 mL.yr-1, less than that generally reported in the past in untreated patients in the same age range. In conclusion, our data suggest that patients with advanced Duchenne's muscular dystrophy with pronounced nocturnal desaturation, not fulfilling criteria for imperative ventilation, could be successfully treated with "elective" nocturnal ventilation with immediate benefits consequent to the correction of the nocturnal blood gas anomalies and with long-term benefits related to the preservation of residual respiratory function, delay of development of chronic hypercapnia and thus the requirement for imperative mechanical ventilation.

Monosomy of distal 4q does not cause facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is a hereditary neuromuscular disorder transmitted in an autosomal dominant fashion. FSHD has been located by linkage analysis in the most distal part of chromosome 4q. The disease is associated with deletions within a 3.2 kb tandem repeat sequence, D4Z4. We have studied a family in which an abnormal chromosome 4 segregates through three generations in phenotypically normal subjects. This chromosome is the derivative of a (4;D or G) (q35;p12) translocation. Molecular analysis of the region 4q35 showed the absence of the segment ranging from the telomere to locus D4F104S1. Probe p13E-11 (D4F104S1), which detects polymorphic EcoRI fragments containing D4Z4, in Southern blot analysis showed only one allele in the carriers of the abnormal chromosome 4. Probe p13E-11 EcoRI fragments are contained in the subtelomeric region of 4q and their rearrangements associated with FSHD suggested that the gene responsible for the muscular dystrophy could be subject to a position effect variegation (PEV) because of its proximity to subtelomeric heterochromatin. The absence of the 4q telomeric region in our phenotypically normal cases indicates that haploinsufficiency of the region containing D4Z4 does not cause FSHD.

Minor neurological and perceptuo-motor deficits in children with congenital muscular dystrophy: correlation with brain MRI changes

Diffuse white matter changes on magnetic resonance imaging (MRI) have been a consistent feature in some children with the "pure" form of congenital muscular dystrophy (CMD) in which there are no structural changes in the brain or severe mental retardation. The aim of this study was to assess fine motor and perceptuo-motor abilities in children with CMD with and without MRI changes. Twenty-two children with "pure" CMD were investigated with a standard neurological examination and a battery of tests (Manual dexterity from the Movement ABC, test of visual-motor integration, Zurich Neuromotor test) which have already been used to detect minor neurological signs related to white matter changes. The cohort was then divided in two groups for analysis depending on the presence or the absence of diffuse white matter changes. A significant difference was found for all the tests between the group of the CMD children with normal MRI and the group with diffuse white matter changes. The manual dexterity and the Zurich Neuromotor tests showed a greater sensitivity than the test of visual-motor integration, which had some false negatives. It is of interest that in the group with diffuse white matter changes the presence of contractures or weakness did not seem to affect the quality of the performance; all these children scored abnormally on the test, irrespective of the severity or the extent of contractures and weakness. In contrast, in children with normal MRI severe contractures and weakness did affect the performances. Our results demonstrate that perceptuo-motor difficulties and minor neurological soft signs are a consistent feature in CMD children with diffuse MRI changes but not with normal MRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of gross motor development in children with SMA type II

The natural history of SMA and the identification of predictive criteria of functional development are still a matter of discussion. This prospective study involved 20 children with SMA, aged between 3.10 and 15.7 years. The patients were followed from 1979 to 1992 in order to try to develop a greater understanding of the natural history of SMA at a very early age. A standardized protocol was used at regular intervals to assess parameters such as joint contractures, scoliosis and the milestones of gross motor functions. Our findings agree with the data in the literature concerning the early and generalized onset of joint contractures and scoliosis. A significant correlation was found between the level of acquired gross motor functions and walking with support. The acquisition of rolling by 5 years of age was the milestone that best correlated with the acquisition of walking with crutches and braces; furthermore the inability to roll seemed to correlate with the severity of the disease. These findings should be useful in planning a more rational rehabilitation program.

Somatosensory and visual evoked potentials in congenital muscular dystrophy: correlation with MRI changes and muscle merosin status

Congenital muscular dystrophy comprises a heterogeneous group of disorders, that have in common an early onset and a dystrophic picture on the muscle biopsy. The "pure" form of congenital muscular dystrophy is not associated with severe mental retardation or structural changes in the brain, though white matter changes on brain imaging have been detected in a significant proportion of cases. In this study we evaluated the incidence of sensory abnormalities (somatosensory and visual evoked responses) in a group of 17 patients with "pure" congenital muscular dystrophy and correlated the results of the evoked responses with the presence or absence of white matter changes on brain magnetic resonance imaging. Our results show close correlation between the presence of MRI white matter changes and abnormalities in the sensory evoked potentials. Conversely, all patients with normal brain MRI had normal somatosensory evoked potentials (SEP). Visual evoked potentials were less sensitive than somatosensory evoked potentials in detecting abnormalities in children with white matter changes on MRI. With the recent discovery of deficiency in merosin expression in the skeletal muscle of a subgroup of patients with CMD, we also correlated the presence or absence of white matter changes and the SEP responses with the merosin status. The results indicate that all merosin-negative patients had abnormal SEP as well as abnormal MRI, whilst no patient with normal merosin expression had an abnormal scan or abnormal SEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and neurophysiological study in diabetic children and adolescents

We investigated 82 unselected insulin dependent diabetes mellitus children and adolescents by clinical and electrophysiological evaluation to assess the frequency of diabetic neuropathy and to relate the results to age and height of patients, duration of illness and degree of metabolic control. Clinical abnormalities were found in about 1/3 of patients: these signs of diabetic neuropathy were related to the age and the duration of diabetes but not to the degree of metabolic control. Neurophysiological study showed alterations, especially of sensory nerve conduction. These results were seen to be related to height and age of patients and duration of illness but not to the degree of metabolic control, probably due to the young age of the patients. Our study confirms that diabetic neuropathy is a heterogeneous disorder that may be caused by the interaction of host susceptibility and vascular, metabolic and perhaps environmental components also in diabetic children.