Septic bursitis in the prepatellar and olecranon bursae: an analysis of 25 cases

Five cases of septic prepatellar and 20 cases of septic olecranon bursitis are reported. All were men, with a mean age of 47 years. Seventeen had a history of recent trauma to the affected limb or sustained pressure on knees or elbows, or both, required by certain occupations. Septic bursitis was not associated with septic arthritis and could be easily distinguished from it by the characteristic bursal swelling and joint examination. Septic bursitis was misdiagnosed as nonseptic bursitis in eight cases despite characterstic bursal fluid leukocytosis (greater than 1000 cells/mm3) and recovery of bacteria on culture. Staphylococcus aureus was identified in 22 cases; 76% were resistant to penicillin. Intravenous antibiotics and bursal fluid drainage were uniformly succesful. Oral antibiotic ttherapy was also successful unless the infection was extensive or there was underlying bursal disease. Early recognition, prompt therapy, and preventive measures are necessary to reduce the morbidity of septic bursitis.

Functional characterization of mutations in melanocortin-4 receptor associated with human obesity

Melanocortin-4 receptor (MC4R) is a G protein-coupled receptor implicated in the regulation of body weight. Genetic studies in humans have identified two frameshift mutations of MC4R associated with a dominantly inherited form of obesity. We have generated and expressed the corresponding MC4R mutants in 293T cells and found that cells transfected with the truncation mutants failed to exhibit agonist binding or responsiveness despite retention of structural motifs potentially sufficient for binding and signaling. Immunofluorescence studies showed that the mutant proteins were expressed and localized in the intracellular compartment but absent from the plasma membrane, suggesting that these mutations disrupted the proper cellular transport of MC4R. Further studies identified a sequence in the cytoplasmic tail of MC4R necessary for the cell surface targeting. We further investigated a possible dominant-negative activity of the mutants on wild-type receptor function. Co-transfection studies showed that the mutants affected neither signaling nor cell surface expression of wild-type MC4R. We also characterized three human sequence variants of MC4R, but these exhibited identical affinities for peptide ligands and identical agonist responsiveness. Thus, unlike the obesity-associated MC4R truncation mutants, the polymorphisms of MC4R are unlikely to be contributors to human obesity.

Potent tetracyclic guanine inhibitors of PDE1 and PDE5 cyclic guanosine monophosphate phosphodiesterases with oral antihypertensive activity

Tetracyclic guanines have been shown to be potent and selective inhibitors of the cGMP-hydrolyzing enzymes PDE1 and PDE5. In general, these compounds are inactive or only weakly active as inhibitors of PDE3, which is a major isozyme involved in cAMP hydrolysis. Structure-activity relationships are developed at N-1, C-2, N-3, and N-5 on the core nucleus. Compound 31, with an IC50 of 70 pM, is the most potent inhibitor of PDE1, while 50, with an IC50 of 4 nM, is the most potent inhibitor of PDE5. Compounds 20, 22, 30, and 50 are potent dual inhibitors with IC50 values below 30 nM for both PDE1 and PDE5. Compounds 12, 20, and 28 reduced blood pressure by more than 45 mmHg when administered orally at 10 mg/kg to the spontaneously hypertensive rat (SHR).

Mitigating ammonia inhibition of thermophilic anaerobic treatment of digested piggery wastewater: use of pH reduction, zeolite, biomass and humic acid

High free ammonia released during anaerobic digestion of livestock wastes is widely known to inhibit methanogenic microorganisms and result in low methane production. This was encountered during our earlier thermophilic semi-continuously fed continuously-stirred tank reactor (CSTR) treatment of piggery wastewater. This study explored chemical and biological means to mitigate ammonia inhibition on thermophilic anaerobic treatment of piggery wastewater with the aim to increase organic volatile carbon reduction and methane production. A series of thermophilic anaerobic batch experiments were conducted on the digested piggery effluent to investigate the effects of pH reduction (pH 8.3 to 7.5, 7.0 and 6.5) and additions of biomass (10% v/v and 19% v/v anaerobic digested piggery biomass and aerobic-anaerobic digested municipal biomass), natural zeolite (10, 15 and 20 g/L) and humic acid (1, 5 and 10 g/L) on methane production at 55 °C for 9-11 days. Reduction of the wastewater pH from its initial pH of 8.3 to 6.5 produced the greatest stimulation of methane production (3.4 fold) coupled with reductions in free ammonia (38 fold) and total volatile fatty acids (58% TVFA), particularly acetate and propionate. Addition of 10-20 g/L zeolite to piggery wastewater with and without pH reduction to 6.5 further enhanced total VFA reduction and methane production over their respective controls, with 20 g/L zeolite producing the highest enhancement effect despite the ammonia-nitrogen concentrations of the treated wastewaters remaining high. Without pH reduction, zeolite concentration up to 20 g/L was required to achieve comparable methane enhancement as the pH-reduced wastewater at pH 6.5. Although biomass (10% v/v piggery and municipal wastes) and low humic acid (1 and 5 g/L) additions enhanced total VFA reduction and methane production, they elevated the residual effluent total COD concentrations over the control wastewaters (pH-unadjusted and pH-reduced) unlike zeolite treatment. The outcomes from these batch experiments support the use of pH reduction to 6.5 and zeolite treatment (10-20 g/L) as effective strategies to mitigate ammonia inhibition of the thermophilic anaerobic treatment of piggery wastewater.

The common BDNF polymorphism may be a modifier of disease severity in Rett syndrome

BACKGROUND

Rett syndrome (RTT) is caused by mutations in the transcriptional repressor methyl CpG-binding protein 2 (MECP2). Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor playing a major role in neuronal survival, neurogenesis, and plasticity, and it has been shown that BDNF expression is regulated by MeCP2 through a complex interaction. A common polymorphism of BDNF (Val66Met [p.V66M]) has been found to correlate with severity and course of several neuropsychiatric disorders.

METHODS

We examined the association between disease severity score, assessed by the modified Percy score, and BDNF polymorphism, using regression methods, in 125 mutation-positive patients with RTT from the Australian Rett Syndrome Database and an Israeli cohort.

RESULTS

Those who were heterozygous (Val/Met) had slightly more severe disease than those who were homozygous for the wild-type (Val/Val) BDNF polymorphism (increased severity score 2.1, p = 0.09). In those with p.R168X, a commonly occurring MECP2 mutation in RTT, there was a 6-point increase in severity score for those who were heterozygous for the BDNF polymorphism, both unadjusted (p = 0.02) and adjusted for age (p = 0.03). Individuals with the p.R168X mutation and heterozygous for the BDNF polymorphism were also at an increased risk of seizure onset (hazard ratio 5.3, 95% confidence interval 1.6-17.7) compared with those homozygous for the wild-type BDNF allele.

CONCLUSIONS

In addition to mutation type and degree of X-chromosome skewing, the common brain-derived neurotrophic factor (BDNF) polymorphism appears to be another genetic modifier of Rett syndrome (RTT) severity. This suggests that BDNF function may play a significant role in the pathogenesis of RTT.

Septic bursitis

Nine cases of septic bursitis are presented, and the literature on the subject comprehensively reviewed, with an emphasis on the clinical manifestations of septic bursitis in various anatomic locations. Physical activities associated with increased susceptibility to septic bursitis and systemic conditions that increase the severity of septic bursitis are catalogued. Analysis of the microbiology of cases reported in the literature demonstrates that greater than 80% of cases of septic bursitis are caused by Staphylococcus aureus and other gram-positive organisms. However, a wide variety of gram-negative microorganisms, fungi, and other infectious agents have been reported to cause septic bursitis and may lead to complications in diagnosis and treatment. The nine cases reported here demonstrate the potential severity of septic bursitis and emphasize that significant systemic complications may result from this common musculoskeletal infection. Indications for hospitalization and/or intravenous antibiotic therapy for septic bursitis include the presence of fulminant local infection, evidence for systemic toxicity, or infection in an immunocompromised patient. Patients who fail to respond to intravenous antibiotics and percutaneous aspiration of the bursa may require surgical drainage or bursectomy by one of several methods that have been proposed. There is some recent evidence that intrabursal corticosteroid injection for therapy of nonseptic subcutaneous bursitis may be more effective than systemic antiinflammatory medication or simple bursa aspiration.

Congenital and childhood myotonic dystrophy: Current aspects of disease and future directions

Myotonic dystrophy type 1 (DM1) is multisystem disease arising from mutant CTG expansion in the non-translating region of the dystrophia myotonica protein kinase gene. While DM1 is the most common adult muscular dystrophy, with a worldwide prevalence of one in eight thousand, age of onset varies from before birth to adulthood. There is a broad spectrum of clinical severity, ranging from mild to severe, which correlates with number of DNA repeats. Importantly, the early clinical manifestations and management in congenital and childhood DM1 differ from classic adult DM1. In neonates and children, DM1 predominantly affects muscle strength, cognition, respiratory, central nervous and gastrointestinal systems. Sleep disorders are often under recognised yet a significant morbidity. No effective disease modifying treatment is currently available and neonates and children with DM1 may experience severe physical and intellectual disability, which may be life limiting in the most severe forms. Management is currently supportive, incorporating regular surveillance and treatment of manifestations. Novel therapies, which target the gene and the pathogenic mechanism of abnormal splicing are emerging. Genetic counselling is critical in this autosomal dominant genetic disease with variable penetrance and potential maternal anticipation, as is assisting with family planning and undertaking cascade testing to instigate health surveillance in affected family members. This review incorporates discussion of the clinical manifestations and management of congenital and childhood DM1, with a particular focus on hypersomnolence and sleep disorders. In addition, the molecular genetics, mechanisms of disease pathogenesis and development of novel treatment strategies in DM1 will be summarised.

Reciprocal relationship of synovial fluid volume and oxygen tension

To investigate the impact of synovial fluid volume on oxygen tension (PO2) and other metabolic correlates, 24 specimens of synovial fluid from the knees of 22 patients were analyzed for volume, number of leukocytes (WBC), pH, PO2, PCO2, glucose, protein, and complement (CH50) levels. Concurrent arterial blood samples were obtained in 21 instances. Synovial fluid PO2 values varied inversely with volumes of synovial fluid (r = -0.54, P less than 0.01), but when patients with rheumatoid arthritis were excluded, the correlation was more significant (r = -0.76, P less than 0.001). When synovial fluid PO2 dropped below 45 mm Hg, intraarticular acidosis resulted. The decrease in pH (r = 0.93, P less than 0.001), the lowering of glucose values (r = 0.89, P less than 0.001), and the rise in PCO2 (r = -0.79, P less than 0.01) can be explained by a shift toward anaerobic metabolism coupled with the impaired elimination of its products. Systemic acidosis and hypoxia were not found. Intraarticular hypoxia most likely represents circulatory imbalance at the level of the synovial membrane, although an inverse relationship of synovial fluid PO2 and WBC was also noted. Complement and protein levels had no correlation with volume, pH, or respiratory gas tensions of synovial fluids. Our data support the importance of the effective blood flow to the joint in maintaining homeostasis. The volume of synovial effusion and the compliance of the joint capsule appear to be important determinants of the articular blood supply.

SCH-202676: An allosteric modulator of both agonist and antagonist binding to G protein-coupled receptors

A novel thiadiazole compound, SCH-202676 (N-(2,3-diphenyl-1,2, 4-thiadiazol-5-(2H)-ylidene)methanamine), has been identified as an inhibitor of both agonist and antagonist binding to G protein-coupled receptors (GPCRs). SCH-202676 inhibited radioligand binding to a number of structurally distinct, heterologously expressed GPCRs, including the human mu-, delta-, and kappa-opioid, alpha- and beta-adrenergic, muscarinic M1 and M2, and dopaminergic D1 and D2 receptors, but not to the tyrosine kinase epidermal growth factor receptor. SCH-202676 had no direct effect on G protein activity as assessed by [35S]guanosine-5'-O-(gamma-thio)triphosphate binding to purified recombinant G(oalpha)- or G(betagamma)-stimulated ADP-ribosylation of G(oalpha) by pertussis toxin. In addition, SCH-202676 inhibited antagonist binding to the beta2-adrenergic receptor expressed in Escherichia coli, a system devoid of classical heterotrimeric G proteins. SCH-202676 inhibited radiolabeled agonist and antagonist binding to the alpha2a-adrenergic receptor with an IC50 value of 0.5 microM, decreased the Bmax value of the binding sites with a slight increase in the KD value, and inhibited agonist-induced activation of the receptor. The effects of SCH-202676 were reversible. Incubation of plasma membranes with 10 microM SCH-202676 did not alter subsequent radioligand binding to the alpha2a-adrenergic receptor and the dopaminergic D1 receptor. Taken together, our data suggest that SCH-202676 has the unique ability to allosterically regulate agonist and antagonist binding to GPCRs in a manner that is both selective and reversible. The scope of the data presented suggests this occurs by direct interaction with a structural motif common to a large number of GPCRs or by activation/inhibition of an unidentified accessory protein that regulates GPCR function.

Adequacy of anticoagulation in patients with atrial fibrillation coming to a hospital

STUDY OBJECTIVE

To evaluate the adequacy of anticoagulation in patients with atrial fibrillation (AF) coming to a hospital.

DESIGN

Retrospective medical record review.

SETTING

Tertiary care hospital.

PATIENTS

Consecutive patients with a history of AF who had been prescribed warfarin and who had the international normalized ratio (INR) measured when they arrived at the hospital. Those who developed AF as a complication during hospitalization were excluded.

MEASUREMENTS AND MAIN RESULTS

Of 1085 patients, 375 (mean age 73 yrs, 56.3% men) were eligible for further evaluation. Most had nonvalvular AF; in 44.5% the INR was subtherapeutic, in 36.5% it was therapeutic, and in 18.9% it was supratherapeutic. Patients admitted for any thromboembolic event and for ischemic stroke were significantly more likely to have subtherapeutic INRs.

CONCLUSION

It is well documented in the literature that warfarin is underprescribed, but our results suggest that even in treated patients, about half are inadequately protected from thromboembolism.

Updating the profile of C-terminal MECP2 deletions in Rett syndrome

OBJECTIVES

This study aimed to compare the phenotype of Rett syndrome cases with C-terminal deletions to that of cases with different MECP2 mutations and to examine the phenotypic variation within C-terminal deletions.

METHODS

Cases were selected from InterRett, an international database and from the population-based Australian Rett Syndrome Database. Cases (n=832) were included if they had a pathogenic MECP2 mutation in which the nature of the amino acid change was known. Three severity scale systems were used, and individual aspects of the phenotype were also compared.

RESULTS

Lower severity was associated with C-terminal deletions (n=79) compared to all other MECP2 mutations (e.g. Pineda scale C-terminals mean 15.0 (95% CI 14.0-16.0) vs 16.2 (15.9-16.5). Cases with C-terminal deletions were more likely to have a normal head circumference (odds ratio 3.22, 95% CI 1.53 - 6.79) and weight (odds ratio 2.97, 95% CI 1.25-5.76). Onset of stereotypies tended to be later (median age 2.5 years vs 2 years, p<0.001 from survival analysis), and age of learning to walk tended to be earlier (median age 1.6 years vs 2 years, p=0.002 from survival analysis). Those with C-terminal deletions occurring later in the region had lower average severity scores than those occurring earlier in the region.

CONCLUSION

In terms of overall severity C-terminal deletion cases would appear to be in the middle of the range. In terms of individual aspects of phenotype growth and ability to ambulate appear to be particular strengths. By pooling data internationally this study has achieved the case numbers to provide a phenotypic profile of C-terminal deletions in Rett syndrome.

Targeted disruption of the Dictyostelium myosin essential light chain gene produces cells defective in cytokinesis and morphogenesis

We have previously demonstrated that the myosin essential light chain (ELC) is required for myosin function in a Dictyostelium cell line, 7–11, in which the expression of ELC was inhibited by antisense RNA overexpression. We have now disrupted the gene encoding the ELC (mlcE) in Dictyostelium by gene targeting. The mlcE- mutants provide a clean genetic background for phenotypic analysis and biochemical characterization by removing complications arising from the residual ELC present in 7–11 cells, as well as the possibility of mutations due to insertion of the antisense construct at multiple sites in the genome. The mlcE- mutants, when grown in suspension, exhibited the typical multinucleate phenotype observed in both myosin heavy chain mutants and 7–11 cells. This phenotype was rescued by introducing a construct that expressed the wild-type Dictyostelium ELC cDNA. Myosin purified from the mlcE- cells exhibited significant calcium ATPase activity, but the actin-activated ATPase activity was greatly reduced. The results obtained from the mlcE- mutants strengthen our previous conclusion based on the antisense cell line 7–11 that ELC is critical for myosin function. The proper localization of myosin in mlcE- cells suggests that its phenotypic defects primarily arise from defective contractile function of myosin rather than its mislocalization. The enzymatic defect of myosin in mlcE- cells also suggests a possible mechanism for the observed chemotactic defect of mlcE- cells. We have shown that while mlcE- cells were able to respond to chemoattractant with proper directionality, their rate of movement was reduced. During chemotaxis, proper directionality toward chemoattractant may depend primarily on proper localization of myosin, while efficient motility requires contractile function. In addition, we have analyzed the morphogenetic events during the development of mlcE- cells using lacZ reporter constructs expressed from cell type specific promoters. By analyzing the morphogenetic patterns of the two major cell types arising during Dictyostelium development, prespore and prestalk cells, we have shown that the localization of prespore cells is more susceptible to the loss of ELC than prestalk cells, although localization of both cell types is abnormal when developed in chimeras formed by mixing equal numbers of wild-type and mutant cells. These results suggest that the morphogenetic events during Dictyostelium development have different requirements for myosin.

Role of heparan sulfate proteoglycans in the uptake and degradation of tissue factor pathway inhibitor-coagulation factor Xa complexes

Tissue factor pathway inhibitor (TFPI) is a potent inhibitor of blood coagulation factor Xa (fXa) and factor VIIa. We have recently shown that fXa binding stimulates the uptake and degradation of cell surface-bound 125I-TFPI (Ho, G., Toomey, J. R., Broze, G. J., Jr., and Schwartz, A. L. (1996) J. Biol. Chem. 271, 9497-9502). In the present study we examined the role of cell surface glycosaminoglycans (GAGs) in this process. Removal of cell surface GAG chains by treatment of cells with heparinase or heparitinase but not chondroitinase markedly reduced fXa-stimulated 125I-TFPI uptake and degradation. Inhibition of GAG sulfation by growth of cells in chlorate-containing medium similarly decreased fXa-stimulated 125I-TFPI degradation. These results suggest that heparan sulfate proteoglycans (HSPGs) are required for the uptake and degradation of 125I-TFPI.fXa complexes. Chemical cross-linking/immunoprecipitation analyses revealed that 125I-TFPI was directly associated with HSPGs on the cell surface and that fXa binding increased the amount of 125I-TFPI bound. Of the several cell lines evaluated, bend endothelial cells demonstrated the greatest fXa stimulation of 125I-TFPI uptake and degradation. Cross-linking/immunoprecipitation analyses on bend cells also revealed that HSPGs were specifically associated with TFPI and fXa. These data suggest that HSPGs may directly act as the uptake and degradation receptor for TFPI.fXa complexes.

Quantitative sacroiliac joint scintigraphy. A critical assessment

With quantitative sacroiliac joint scintigraphy (QSS), sacroiliac joint-to-sacrum (SIS) ratios greater than or equal to 1.40 are abnormal for our method. High SIS ratios are associated with roentgenographically appreciated sacroiliitis and with early clinically evident sacroiliitis. Although highly sensitive, QSS abnormalities are not specific for inflammatory sacroiliac (SI) joint disease. High SIS ratios are also seen in rheumatoid arthritis, degenerative abnormalities of the lumbosacral spine, and metabolic bone disorder. Other disorders with roentgenographic SI joint abnormalities must be studied scintigraphically before QSS can be employed as a useful diagnostic test.

Evaluation of the effect of norfloxacin on the pharmacokinetics of theophylline

To investigate a possible interaction between norfloxacin and theophylline, eight healthy nonsmoking volunteers (mean age 27 +/- 5.3 years) were administered aminophylline, 5 mg/kg, before and after a 6-day course of norfloxacin, 400 mg every 12 hours, and changes in pharmacokinetic parameters were measured and compared. Norfloxacin induced significant decreases in theophylline clearance (14.9%; p less than 0.01) and the terminal phase slope (13.3%; p less than 0.02) and increased the AUC (16.6%; p less than 0.01). The apparent volume of distribution at steady state was unchanged. The greatest norfloxacin-induced individual change in theophylline clearance was a reduction of 28.6%. Given these findings, we advise that, for patients who are treated with theophylline and are subsequently treated with norfloxacin, adjustment of the theophylline dosage may be necessary in some patients to minimize the risk of theophylline toxicity.

Antibiotic therapy of septic bursitis. Its implication in the treatment of septic arthritis

Infected olecranon, prepatellar, and infrapatellar bursae offer a unique opportunity to study the response of a closed-space infection to antibiotic therapy. Using percutaneous needle aspirations, serial bursal fluids were cultured. The length of time necessary to achieve culture sterility with antibiotic therapy (an average of 4 days in 25 patients) was correlated with the duration of symptoms prior to diagnosis (r = 0.68, P less than 0.001). In patients treated within 2 weeks from onset of symptoms, bursal fluid sterility was achieved within 1 week of therapy, while longer duration of symptoms was associated with delayed response. When antibiotic therapy was continued for 5 additional days after documented culture sterility, all 19 patients in the prospective trial were cured (average followup period of 6.8 months). In septic bursitis, the effects of delay in treatment are deleterious by prolonging culture-positivity despite adequate antibiotic therapy. By analogy, delay in treatment of septic arthritis may result in the persistence of an adverse environment which can lead to further articular damage. After accurate diagnosis of septic bursitis, a therapeutic approach consisting of prompt and appropriate antibiotic usage, frequent needle drainage, and treatment duration based on the culture results of serial aspirations is effective and may be applicable in the management of certain nongonococcal bacterial joint infections.

Visual search for traffic signs: the effects of clutter, luminance, and aging

Latency and eye movement measures were used to examine the effects of aging, clutter, and luminance on visual search for traffic signs embedded in digitized images of driving scenes. Initially 14 older and 14 younger observers classified daytime and nighttime traffic scenes as containing low or high amounts of clutter. Next, an independent sample of 14 younger and 14 older participants searched for traffic signs contained within these scenes. Errors were more common among the elderly. Search efficiency declined with increased clutter and with aging. However, relative to the young, older adults did not suffer disproportionately as a result of increased clutter. The methods developed might be profitably employed to assess sign conspicuity and sign acquisition during driving.

Urate-mediated inflammation in nodal osteoarthritis: clinical and roentgenographic correlations

We studied 25 patients with crystal-proven gout or roentgenographic evidence of gouty arthritis, or both, in finger joints involved with nodal osteoarthritis (OA). These patients were elderly (mean age 71.4 years), and 72% of them were receiving diuretic therapy. Roentgenographic findings, in addition to features typical of OA, included soft tissue densities (tophi), with or without calcification, large intraarticular erosions, characteristic nonmarginal cortical erosions, and periarticular osteolysis. We conclude that urate crystals mediate episodes of acute inflammation in certain patients with nodal OA. This association is noted primarily in elderly patients of both sexes, especially in those receiving diuretic therapy.

Two-dimensional echocardiographic detection of preclinical aortic root abnormalities in rheumatoid variant diseases

Two-dimensional echocardiographic findings of subaortic fibrous ridging, aortic leaflet thickening, and aortic root dilatation and thickening are described in a group of 36 patients with rheumatoid variant diseases. The group consisted of 25 patients with ankylosing spondylitis, nine patients with Reiter's syndrome, and two patients with inflammatory bowel disease and spondylitis. No patient had clinical or laboratory evidence of aortic regurgitation or heart block. Subaortic fibrous ridging or marked leaflet thickening was noted in 11 of 36 patients; in contrast, no such changes were found in an age-matched control group of 29 men. The subgroup of patients with subaortic fibrous ridging or leaflet thickening (11 patients) had significantly longer disease duration (28.1 versus 17.7 years) and higher incidence of aortic root echo-density (82 versus 36 percent) than the remaining patients. It is concluded that a significant portion of patients with ankylosing spondylitis or Reiter's syndrome have echocardiographic evidence of aortic root involvement prior to the clinical onset of aortic regurgitation.

Transient multiple acyl-CoA dehydrogenation deficiency in a newborn female caused by maternal riboflavin deficiency

A newborn female presented on the first day of life with clinical and biochemical findings consistent with multiple acyl-CoA dehydrogenase deficiency (MADD). Riboflavin supplementation corrected the biochemical abnormalities 24 h after commencing the vitamin. In vitro acylcarnitine profiling in intact fibroblasts both in normal and riboflavin depleted media showed normal oxidation of fatty acids excluding defects in electron transfer flavoprotein (ETF), or ETF ubiquinone oxidoreductase (ETF:QO), or a genetic abnormality in flavin metabolism. In addition, sequencing of the genes encoding ETF and ETF:QO in the proband did not reveal any pathogenic mutations. Determination of the maternal riboflavin status after delivery showed that the mother was riboflavin deficient. Repeat testing done two years after the infant's birth and while on a normal diet showed that the mother was persistently riboflavin deficient and showed a typical MADD profile on plasma acylcarnitine testing. A possible genetic defect in riboflavin transport of metabolism in the mother is postulated to be the cause of the transient MADD seen in the infant. Sequencing of the SLC16A12, RFK and FLAD1 genes encoding key enzymes in riboflavin transport of metabolism in the mother did not identify any pathogenic mutations. The underlying molecular basis of the mother's defect in riboflavin metabolism remains to be established.

Myotonic dystrophy type 1: clinical manifestations in children and adolescents

OBJECTIVE

Myotonic dystrophy type 1 (DM1) is an autosomal-dominant neuromuscular disease with variable severity affecting all ages; however, current care guidelines are adult-focused. The objective of the present study was to profile DM1 in childhood and propose a framework to guide paediatric-focused management.

DESIGN, SETTING AND PATIENTS

40 children with DM1 (mean age 12.8 years; range 2-19) were studied retrospectively for a total of 513 follow-up years at Sydney Children's Hospital. 143 clinical parameters were recorded.

RESULTS

The clinical spectrum of disease in childhood differs from adults, with congenital myotonic dystrophy (CDM1) having more severe health issues than childhood-onset/juvenile patients (JDM1). Substantial difficulties with intellectual (CDM1 25/26 96.2%; JDM1 9/10, 90.0%), fine motor (CDM1 23/30, 76.6%; JDM1 6/10, 60.0%), gastrointestinal (CDM1 17/30, 70.0%; JDM1 3/10, 30.0%) and neuromuscular function (CDM1 30/30, 100.0%; JDM1 25/30, 83.3%) were evident.

CONCLUSION

The health consequences of DM1 in childhood are diverse, highlighting the need for paediatric multidisciplinary management approaches that encompass key areas of cognition, musculoskeletal, gastrointestinal, respiratory, cardiac and sleep issues.