LPIN1 deficiency with severe recurrent rhabdomyolysis and persistent elevation of creatine kinase levels due to chromosome 2 maternal isodisomy.

Fatty acid oxidation disorders and lipin-1 deficiency are the commonest genetic causes of rhabdomyolysis in children. We describe a lipin-1-deficient boy with recurrent, severe rhabdomyolytic episodes from the age of 4 years. Analysis of the LPIN1 gene that encodes lipin-1 revealed a novel homozygous frameshift mutation in exon 9, c.1381delC (p.Leu461SerfsX47), and complete uniparental isodisomy of maternal chromosome 2. This mutation is predicted to cause complete lipin-1 deficiency. The patient had six rhabdomyolytic crises, with creatine kinase (CK) levels up to 300,000 U/L (normal, 30 to 200). Plasma CK remained elevated between crises. A treatment protocol was instituted, with early aggressive monitoring, hydration, electrolyte replacement and high caloric, high carbohydrate intake. The patient received dexamethasone during two crises, which was well-tolerated and in these episodes, peak CK values were lower than in preceding episodes. Studies of anti-inflammatory therapy may be indicated in lipin-1 deficiency.

A new form of congenital muscular dystrophy with joint hyperlaxity maps to 3p23-21.

Congenital muscular dystrophies (CMDS) are a heterogeneous group of disorders. A growing number of CMDS have been found to be associated with joint hyperlaxity. We recruited 14 French-Canadian cases belonging to 11 families affected by a novel autosomal recessive congenital muscular dystrophy with hyperlaxity (CMDH). All cases come from the southwestern part of Quebec, suggesting a new French-Canadian founder effect. All patients present muscle weakness, proximal contractures coexisting with distal joint hyperlaxity. Pathological and genetic studies have excluded that mutations in the three genes coding for collagen VI subunits are responsible for this disease. A genome-wide scan established linkage of two CMDH families to a region on chromosome 3p23-21. Further linkage analysis confirmed that all families are linked to the same region (log of the odds score of 5.3). Haplotype analysis defines a 1.6-cM candidate interval and suggests that two common mutations may account for 78% of carrier chromosomes. This study describes and maps a new form of recessive CMD with joint hyperlaxity distinct from Ullrich and Bethlem myopathies with a founder effect in the French-Canadian population.

A new autosomal recessive spastic ataxia associated with frequent white matter changes maps to 2q33-34.

Recessive ataxias are a heterogeneous group of diseases. We identified a group of 23 French-Canadian cases belonging to 17 families affected by an autosomal recessive spastic ataxia associated with frequent white matter changes. The fact that 59% of these families have a genealogical relationship to the Portneuf County of Quebec suggests that this is a new form of ataxia with a regional founder effect. All cases present with cerebellar ataxia and spasticity. There is great intrafamilial and interfamilial variability, as illustrated by the spectrum of age of diagnosis (range: 2-59 years, mean: 15.0) and the presence of white matter changes on MRI in 52.4% of cases. The more severe cases have spasticity from birth, scoliosis, dystonia and cognitive impairment and were considered cases of cerebral palsy. Brain MRI constantly shows cerebellar atrophy, which in some cases may be associated with cortical atrophy, leucoencephalopathy and corpus callosum thinning. A genome wide scan uncovered linkage of three families to marker D2S2321 localized on chromosome 2q33-34. Linkage analysis confirmed that all families are linked to the same region [multipoint log of the odds (LOD) score of 5.95]. Haplotype analysis and allele sharing suggest that one common mutation may account for 97% of carrier chromosomes in Quebec. The uncovering of the mutated gene may point to a common pathway for pyramidal and cerebellar degeneration as both are often observed in recessive ataxias and complicated paraplegias.

Two mutations in the HSN2 gene explain the high prevalence of HSAN2 in French Canadians.

BACKGROUND: Hereditary sensory and autonomic neuropathy type 2 (HSAN2; MIM 201300) is a rare recessive neuropathy typically diagnosed in the first decade. The 1973 study of a French Canadian family led to the definition of HSAN2. OBJECTIVES: To demonstrate that the apparent higher prevalence of HSAN2 in Quebec is due to the presence of two HSN2 mutations and that carriers of different mutations appear to have a similar phenotype. METHODS: Through attending physicians, the authors recruited French Canadian patients with HSAN2. Exclusion of linkage to the known HSAN loci and linkage to the HSAN2 was performed using standard methods. Sequencing of the HSN2 gene was used to uncover the causal mutations. RESULTS: A large cluster of HSAN2 patients comprising 16 affected individuals belonging to 13 families was identified. The mode of inheritance is clearly autosomal recessive. All patients originated from southern Quebec, and 75% are from the Lanaudière region. Whereas linkage to the HSAN1, 3, and 4 loci was excluded, linkage to the 12p13.33 HSAN2 locus was confirmed. Sequencing of the HSN2 gene uncovered two French Canadian mutations and a novel nonsense mutation in a patient of Lebanese origin, all predicted to lead to truncations of the HSN2 protein. The comparison of clinical variables between patients with different genotypes does not suggest any difference in phenotype. CONCLUSIONS: Two founder mutations are responsible for the apparently higher prevalence of HSAN2 in French Canadians. Genotype-phenotype correlation does not suggest any significant clinical variability.

Hyperbaric oxygen for children with cerebral palsy: a randomised multicentre trial. HBO-CP Research Group.

BACKGROUND: The use of hyperbaric oxygen for children with cerebral palsy has spread worldwide, despite little scientific evidence of efficacy. We did a randomised trial to assess the efficacy and side-effects of this form of therapy in children with cerebral palsy. METHODS: 111 children with cerebral palsy aged 3-12 years were randomly assigned hyperbaric oxygen (n=57) or slightly pressurised room air (n=54). All children received 40 treatments over 2 months. Hyperbaric oxygen treatment was 1 h in 100% oxygen at 1.75 atmospheres absolute (ATA); children on slightly pressurised air received air at 1.3 ATA (the lowest pressure at which pressure can be felt, thereby ensuring the maintenance of masking). The main outcome measure was gross motor function. Secondary outcomes included performance in activities of daily living, attention, working memory, and speech. FINDINGS: For all outcomes, both groups improved over the course of the study, but without any difference between the two treatments. The score on the global gross motor function measure increased by 3.0% in the children on slightly pressurised air and 2.9% in those on hyperbaric oxygen. The mean difference between treatments was -0.40 (95% CI -1.69 to 0.90, p=0.544). Other changes were seen in speech, attention, memory, and functional skills. Ear problems occurred in 27 children treated by hyperbaric oxygen and in 15 treated with hyperbaric air (p=0.004). INTERPRETATION: In this study, hyperbaric oxygen did not improve the condition of children with cerebral palsy compared with slightly pressurised air. The improvement seen in both groups for all dimensions tested deserves further consideration.

Clinical and electrophysiological study in French-Canadian population with Charcot-Marie-tooth disease type 1A associated with 17p11.2 duplication.

BACKGROUND: The aim of the present study was to examine the frequency and the phenotypic manifestations in a French-Canadian population with a chromosome 17p11.2 duplication (Charcot-Marie-Tooth type 1A, CMT-1A). METHODS: Molecular analysis were performed by Southern blot using pVAW409R3a probe. Clinical evaluation was carried out according to the scale defined by the European HMSN Consortium. RESULTS: The frequency of duplication was found to be similar in the adult (70.8%) and pediatric (72.7%) populations. Onset of symptoms occurred before 20 years of age in 85.7% of adult cases and before the age of 5 in 80% of the pediatric cases. The classical CMT syndrome was observed in 77% of the cases and the syndrome was associated with additional features in 15% of cases in the adult population. All the children presented with classical CMT syndrome with no additional features. There was a significant correlation between the disability score and the duration of the disease but no correlation was found between median nerve conduction velocity and the functional handicap, the age at onset or the duration of the disease. In one family, there was a very conspicuous anticipation over five observed generations. CONCLUSION: This study reveals that the age at onset, the clinical and electrophysiological variability as well as the functional disability variations in a French-Canadian population did not differ from those reported in other populations.

Pain and the Guillain-Barré syndrome in children under 6 years old.

During a 15-year period, 29 children, under the age of 6 years, with acute Guillain-Barré syndrome were seen at our institution. A review of their charts revealed that pain was a symptom in all patients and was present on admission in 79% of cases. Pain was often the most important symptom and led to misdiagnosis in 20 patients (69%). In 11 of these children, symptoms were present for more than a week before the correct diagnosis was made. The most common pain syndrome was back and lower limb pain, present in 83% of patients. Pediatricians should consider Guillain-Barré syndrome in their differential diagnosis when faced with a child who has lower limb pain and areflexia.

Effects of hyperbaric oxygen therapy on children with spastic diplegic cerebral palsy: a pilot project.

Hyperbaric oxygen (HBO2) therapy for children with cerebral palsy (CP) is not new. Research documenting the effects in this population has been anecdotal. We evaluated the effects of HBO2 therapy for 25 children (X = 5.6 +/- 1.6 yr) with a functional diagnosis of spastic diplegic CP. Pre- and post-HBO2 evaluations consisted of the following measures: gross motor function measure (GMFM), fine motor function (Jebsen test for hand function), spasticity (modified Ashworth scale), video analysis, and parental questionnaire. The protocol for HBO2 therapy was 20 treatments of 95% oxygen at 1.75 atm abs for 60 min. The Wilcoxon matched-pairs signed-rank test for non-parametric measures was used to compare pre- and post-treatment data. Results showed improved gross motor function in three of the five items in the GMFM test, improved fine motor function in three of the six hand tests, reduced spasticity in three of four muscle groups when assessed by a physician specializing in CP, and improvements for four of nine questions posed to parents.

SMN(T) and NAIP mutations in Canadian families with spinal muscular atrophy (SMA): genotype/phenotype correlations with disease severity.

Childhood-onset spinal muscular atrophy (SMA) is an autosomal recessive neuropathy characterized by selective degeneration of alpha-motor neuron cells of the spinal cord. Age of onset and motor development varies greatly among patients, but the molecular basis of this variability remains unclear. The SMA locus contains two copies of a 500-kb element and deletions within the telomeric element have been shown to be the most common cause of SMA. To study the relationship between genotype and phenotype, 60 SMA families, all but two of which are of French Canadian origin, were screened for deletions in the telomeric survival motor neuron (SMN(T)) and the intact neuronal apoptosis inhibitory protein (NAIP) genes. Combining these results with those obtained for the multicopy microsatellite marker Ag1-CA (D5S1556) indicated that there are at least two types of SMA alleles. Most type I SMA patients are homozygous for large scale deletions involving the entire SMN(T) gene as well as exons 5 and 6 of the NAIP gene. The strong association between the 100-bp allele of Ag1-CA and large scale deletions in populations of diverse ethnic origin suggests that this allele marks an unstable or founder SMA chromosome. In contrast, most chronic SMA patients have at least one SMA allele with either an intragenic SMN(T) deletion or a SMN(C):SMN(T) chimeric gene which replaces the normal SMN(T) gene. The broad continuum of disease presentation in chronic SMA is most likely a consequence of the interaction between different SMA alleles.

Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion.

We studied genotype-phenotype correlations in a group of 100 patients with typical Friedreich ataxia (FRDA), and in three groups of patients with atypical clinical presentations, including 44 Acadian FRDA, 8 late-onset FRDA (LOFA), and 6 FRDA with retained reflexes (FARR). All patients, except 3 with typical FRDA, carried two copies of the FRDA-associated GAA triplet repeat expansion. Overall, the phenotypic spectrum of FRDA appeared to be wider than defined by the currently used diagnostic criteria. Our study indicated the existence of several sources of variability in FRDA. Patients with larger GAA expansions tended to have earlier onset and were more likely to show additional manifestations of the disease. Mitotic instability of the expanded GAA repeats may partially account for the limited degree of correlation between expansion sizes as determined in lymphocytes and clinical parameters. Some clinical variants associated with specific FRDA haplotypes, such as Acadian FRDA and FARR, turned out to be unrelated to expansion sizes. No polymorphism in the frataxin coding sequence could be associated with these clinical variants.

Molecular diagnosis of non-deletion SMA patients using quantitative PCR of SMN exon 7.

The telomeric survival motor neuron (SMN(T)) gene is a valuable molecular diagnostic tool for childhood-onset spinal muscular atrophy (SMA) as homozygous deletions of SMN(T) exon 7 (delta7SMN(T)) are present in approximately 94% of patients. In this report, we provide the first comprehensive study of 32 unrelated non-deletion SMA patients. Quantitative polymerase chain reaction (PCR) studies established that 90% had two intact copies of SMN(T) exon 7 suggesting that these patients do not have 5q SMA. Once 5q SMA is confirmed, the SMN(T) gene can be screened for subtle mutations. Using single strand conformation analysis, we identified two missense mutations (P245L and Y272C) in exon 6 of the SMN(T) gene of two SMA patients shown to have a single copy of SMN(T) exon 7. Y272 is most likely critical for SMN(T) function as it is a target for recurring mutations and is associated with type I SMA. These results emphasize the need for dosage analysis in the differential diagnosis of 5q SMA in nondeletion patients, consistent with extensive clinical heterogeneity and some genetic heterogeneity in this disease. Homozygosity or heterozygosity for a delta7SMN(T) allele confirms the diagnosis of 5q SMA with greater precision than clinical examination alone.

Clinical and genetic study of chronic (types II and III) childhood onset spinal muscular atrophy.

We have conducted a retrospective study of 63 patients affected by chronic forms of spinal muscular atrophy (SMA) to better document the natural history of this disease. Thirty-nine patients had type II and 24 type III SMA. These patients had manual muscle testing (MMT) and forced vital capacity (FVC) studies done every six to 12 months over follow up period ranging from six to 140 months. A decline in FVC was seen in both types of SMA but there was no significant change in MMT in either group. Genetic studies were also done in a subset of 17 families (23 patients) included in this study. Homozygous deletions in the telomeric survival motor neuron (SMN) and the neuronal apoptosis inhibitory protein (NAIP) genes were observed in 100% and 11.8% of the patients tested respectively.

Alu-PCR combined with non-Alu primers reveals multiple polymorphic loci.

A marker suitable for genetic mapping and genomic fingerprinting is characterized by high polymorphic information content (PIC) and high "multiplex ratio" (defined as the number of loci that can be simultaneously typed). Towards this goal, we combined an Alu-specific with a non-Alu primer in a single PCR amplification targeting genomic regions where length polymorphisms are abundant. Three loci were revealed with the variable number of (AAT), (TAAA), (AG), and/or (AAAGG) motifs, and PIC values between 0.7 and > 0.94. Their location on Chromosomes (Chrs) 19q12, 17q12-q24, and 5q31.2-33.3 was determined by multipoint analysis with markers from CEPH database. The most common genotype for this three-locus marker, estimated from the occurrence of the most frequent alleles, is of the order of 2 x 10(-4), while the combined PIC value of a single typing experiment is 2.37. The use of a similar primer pair, as well as examples from the literature, indicates the general nature of this approach when a non-Alu oligonucleotide, presumably with "random" priming sites downstream of Alu repeats, is combined with an Alu-specific one. Clustering of DNA length variants in the regions adjacent to interspersed repeats provides opportunity to develop other highly informative multiple-locus markers similar to that described here.

Serum guanidino compound levels in uremic pediatric patients treated with hemodialysis or continuous cycle peritoneal dialysis. Correlations between nerve conduction velocities and altered guanidino compound concentrations.

Serum levels of twelve guanidino compounds (GCs) and nerve conduction velocities were determined in a dialyzed renal insufficient pediatric population. Two dialytic groups were considered: one subjected to hemodialysis (HD, 11 patients) and one subjected to continuous cycle peritoneal dialysis (CCPD, 13 patients). Before HD, marked increases were found for guanidino-succinic acid (207 times), methylguanidine (> or = 67 times), argininic acid (24 times), creatinine and alpha-N-acetylarginine (18 times) and guanidine (> or = 14 times) when compared to controls. Important significant increases were still present after an HD session for guanidinosuccinic acid (49 times), methylguanidine (34 times), creatinine (7 times) and alpha-N-acetylarginine and guanidine (6 times). After HD, creatine, arginine and homoarginine were lower than in controls. All GCs, with the exception of creatine, decreased significantly after a single HD session with percentage decrease ranging between 40% (for arginine) and 77% (for guanidinosuccinic acid). Creatine decreased in a statistically nonsignificant manner by 48%. Marked increases were found in the CCPD group for guanidinosuccinic acid (114 times), alpha-N-acetylarginine (12 times), argininic acid (15 times), creatinine (22 times), guanidine (> or = 11 times) and methylguanidine (> or = 48 times). Concentrations of guanidinosuccinic acid before and after HD and in CCPD were comparable to those reported to be toxic in vitro and in vivo. No clinical or electrophysiological indications of polyneuropathy were observed in our population. Sensory and motor nerve conduction studies showed few abnormalities apart from a significant correlation between argininic acid concentration or guanidine levels and the peroneal nerve conduction velocity in the CCPD-treated group.

Linkage disequilibrium analysis of childhood-onset spinal muscular atrophy (SMA) in the French-Canadian population.

Spinal muscular atrophy (SMA) is, after Duchenne muscular dystrophy, the most common neuromuscular disorder in childhood. The gene responsible for childhood SMA has been mapped to the q11.2-q13.3 region of chromosome 5. We have extended our linkage studies of SMA in the French-Canadian population to include microsatellite markers at the D5S125, D5S351, D5S435, JK53CA1/2 and MAP1B loci. These markers span about 4 cM of the SMA candidate region. We observed significant evidence for linkage between SMA and all the markers tested. The analysis of recombinant chromosomes provide evidence for the following genetic order: D5S125-D5S435-MAP1B-3'-JK53CA1/2 and places D5S351 proximal to JK53CA1/2. Furthermore, we confirm the current localization of the SMA gene distal to D5S435. Finally, we provide demonstration of significant linkage disequilibrium between childhood-onset SMA and four of the five marker loci, D5S125, D5S435, D5S351 and JK53CA1/2. Analysis of SMA-region haplotypes suggests that there may be a predominant SMA allele that is present on about 17% of SMA chromosomes in this sample of the French-Canadian population. We conclude that the observed linkage disequilibrium is likely due to genetic drift among regions of Quebec, consistent with this population's early history.

Myoblast transfer in Duchenne muscular dystrophy.

One biceps muscle of 8 patients with Duchenne muscular dystrophy was injected at 55 sites with a total of 55 million viable, purified, and contamination-free normal myoblasts (myoblast transfer). The other biceps of each patient was injected with a placebo to serve as a control. The procedure was blinded to the patients, parents, and investigators. Myoblasts derived from a biopsy specimen of the fathers were cultured and purified under strict conditions and carefully screened for microbial contamination. All patients received cyclophosphamide for immunosuppression for 6 or 12 months. No serious complications were observed after myoblast transfer, indicating that the procedure is safe. The overall therapeutic efficiency of myoblast transfer was poor as judged by the results in maximal voluntary force generation, dystrophin content of the muscle, magnetic resonance imaging of the muscle, and the lack of donor-derived DNA and dystrophin messenger RNA in the injected muscle. An improved efficiency of the take of myoblasts might be achieved by using younger cells and injecting the myoblasts with a myonecrotic agent (to increase the prevalence of regeneration) and a basal laminal fenestrating agent.