ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients

Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over 100 genes leading to impaired protein or lipid glycosylation. ALG1 encodes a β1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date 13 mutations in 18 patients from 14 families have been described with varying degrees of clinical severity. We identified and characterized 39 previously unreported cases of ALG1-CDG from 32 families and add 26 new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all 27 patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder.

West syndrome associated with a novel chromosomal anomaly; partial trisomy 8P together with partial monosomy 9P, resulting from a familial unbalanced reciprocal translocation

West syndrome is classified according to the underlying etiology into an acquired West syndrome, a congenital/developmental West syndrome, and West syndrome of unknown etiology. Causes of a congenital/developmental West syndrome are extensive and include chromosomal anomalies. We report on a patient carrying a derivative chromosome originating from the reciprocal unbalanced translocation t (8;9) (p11.2;p22) and presenting with macrocephaly, West syndrome, severe mental motor retardation and hypotonia. As far as we know, this is a new chromosomal anomaly associated with West syndrome.

Multidrug resistance 1 (MDR1) 3435C/T genotyping in childhood drug-resistant epilepsy

INTRODUCTION

A mutation at nucleotide position 3435 in exon 26 of the multidrug resistance 1 (MDR1) gene is the most frequently studied polymorphism in relation to multidrug resistance. However, there are conflicting data as to whether the CC or TT genotype of the 3435C>T polymorphism is associated with drug resistance.

METHODS AND RESULTS

We investigated the association between this polymorphism in drug-resistant childhood epilepsy by comparison with drug-responsive patients. In total, 59 patients with drug-resistant epilepsy, defined as having four or more seizures within a 12-month period while using three or more AEDs, 60 children with drug-responsive epilepsy who had remained seizure-free for 12months on their current AED regimen and 76 healthy children were involved in this study. Genotype frequencies in drug-resistant patients were as follows: 32.2% CC, 44.1% CT, 23.7% TT; in the drug-responsive group: 20.0% CC, 50.0% CT, 30.0% TT; in the control group: 24.3% CC, 50.0% CT, 25.7% TT. Comparison of drug-resistant and drug-responsive patients revealed no significant difference in genotype frequency. The findings of the epilepsy patients were not significantly different from those of the healthy control subjects.

CONCLUSIONS

Our study does not support any significant association between the MDR1 polymorphism and drug-resistant childhood epilepsy.

New hyperekplexia mutations provide insight into glycine receptor assembly, trafficking, and activation mechanisms

Hyperekplexia is a syndrome of readily provoked startle responses, alongside episodic and generalized hypertonia, that presents within the first month of life. Inhibitory glycine receptors are pentameric ligand-gated ion channels with a definitive and clinically well stratified linkage to hyperekplexia. Most hyperekplexia cases are caused by mutations in the α1 subunit of the human glycine receptor (hGlyR) gene (GLRA1). Here we analyzed 68 new unrelated hyperekplexia probands for GLRA1 mutations and identified 19 mutations, of which 9 were novel. Electrophysiological analysis demonstrated that the dominant mutations p.Q226E, p.V280M, and p.R414H induced spontaneous channel activity, indicating that this is a recurring mechanism in hGlyR pathophysiology. p.Q226E, at the top of TM1, most likely induced tonic activation via an enhanced electrostatic attraction to p.R271 at the top of TM2, suggesting a structural mechanism for channel activation. Receptors incorporating p.P230S (which is heterozygous with p.R65W) desensitized much faster than wild type receptors and represent a new TM1 site capable of modulating desensitization. The recessive mutations p.R72C, p.R218W, p.L291P, p.D388A, and p.E375X precluded cell surface expression unless co-expressed with α1 wild type subunits. The recessive p.E375X mutation resulted in subunit truncation upstream of the TM4 domain. Surprisingly, on the basis of three independent assays, we were able to infer that p.E375X truncated subunits are incorporated into functional hGlyRs together with unmutated α1 or α1 plus β subunits. These aberrant receptors exhibit significantly reduced glycine sensitivity. To our knowledge, this is the first suggestion that subunits lacking TM4 domains might be incorporated into functional pentameric ligand-gated ion channel receptors.

Acute disseminated encephalomyelitis in children and adolescents: a single center experience

BACKGROUND

Acute disseminated encephalomyelitis is an immune-mediated disease that produces multiple inflammatory lesions in the brain and spinal cord.

METHODS

This study retrospectively evaluated 15 children with acute disseminated encephalomyelitis in children and adolescents from a single institution in Adana, Turkey.

RESULTS

The patients presented in a seasonal distribution, with 73.3%: (11/15) presenting in winter or spring. The majority of patients (13/15, 86.7%) had a history of acute febrile illness 2 to 40 days before presentation, and five children had serologic evidence of specific triggers: mycoplasma (2 children), influenza-A (H1N1) (1 child), or Epstein-Barr virus. All children were treated with a standard protocol of 3 to 5 days of intravenous administration of methylprednisolone and intravenous immunoglobulin for patients who continued to deteriorate. Oseltamivir and clarithromycin were administered in patients with influenza-A (H1N1) and mycoplasma according to the serology. In 13 patients, all neurologic signs and symptoms resolved after treatment. Only one patient was left with severe neurologic sequelae and another child had recurrent attacks and was ultimately diagnosed with possible multiple sclerosis.

CONCLUSIONS

The present series demonstrates that acute disseminated encephalomyelitis in children occurs predominantly in winter or spring and often follows an upper respiratory tract illness for those along the southern coast of Anatolia (Mediterranean region). Early treatment with immunomodulative agents is recommended and is likely to result in a favorable outcome or full recovery. This study also suggests benefit from antiviral and antibiotic treatment initiated as soon as possible after the onset of illness.

Acute cerebellar ataxia in a pediatric case of Lyme disease and a review of literature

A broad range of neurologic disorders have been described in children with Lyme disease, of which peripheral facial nerve palsy and aseptic meningitis are among the most common. In contrast, there are few reports of cerebellar involvement in pediatric Lyme disease patients. We report the case of a 5-year-old girl seropositive for antibodies against the causative Lyme disease pathogen Borrelia burgdorferi presenting with severe acute cerebellar ataxia from the in southern coast of Anatolia (Mediterranean region).

Acute transverse myelitis in a child with Lyme disease and a review of literature

Acute transverse myelitis is a rare Borellia burgdorferi-related neurologic complication in childhood. We present a 12-year-old girl who was diagnosed with acute transverse myelitis associated with a borreliosis infection. We also review clinical features in all five cases of Borellia burgdorferi-related transverse myelitis in children. We describe here the sixth child with borreliosis-related transverse myelitis.

Novel mutations consolidate KCTD7 as a progressive myoclonus epilepsy gene

BACKGROUND

The progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous disorders characterised by myoclonus, epilepsy, and neurological deterioration. This study aimed to identify the underlying gene(s) in childhood onset PME patients with unknown molecular genetic background.

METHODS

Homozygosity mapping was applied on genome-wide single nucleotide polymorphism data of 18 Turkish patients. The potassium channel tetramerisation domain-containing 7 (KCTD7) gene, previously associated with PME in a single inbred family, was screened for mutations. The spatiotemporal expression of KCTD7 was assessed in cellular cultures and mouse brain tissue.

RESULTS

Overlapping homozygosity in 8/18 patients defined a 1.5 Mb segment on 7q11.21 as the major candidate locus. Screening of the positional candidate gene KCTD7 revealed homozygous missense mutations in two of the eight cases. Screening of KCTD7 in a further 132 PME patients revealed four additional mutations (two missense, one in-frame deletion, and one frameshift-causing) in five families. Eight patients presented with myoclonus and epilepsy and one with ataxia, the mean age of onset being 19 months. Within 2 years after onset, progressive loss of mental and motor skills ensued leading to severe dementia and motor handicap. KCTD7 showed cytosolic localisation and predominant neuronal expression, with widespread expression throughout the brain. None of three polypeptides carrying patient missense mutations affected the subcellular distribution of KCTD7.

DISCUSSION

These data confirm the causality of KCTD7 defects in PME, and imply that KCTD7 mutation screening should be considered in PME patients with onset around 2 years of age followed by rapid mental and motor deterioration.

Gaucher disease with communicating hydrocephalus and cardiac involvement

A 14-year-old female with Gaucher disease presented with hydrocephalus, corneal opacities, cirrhosis, and cardiac valvular involvement. A homozygous D409H mutation was identified. She underwent surgery for aortic and mitral valve replacement. Because of severe calcification of the aortic root, no successful valve replacement was performed. She died on the third day after the explorative cardiac surgery. Cardiac abnormalities represent a life-threatening presentation of the homozygous D409H mutation. Identification of this type is essential prior to initiating appropriate therapy with enzyme replacement and cardiac corrective surgery.

Obesity and Paediatric Migraine

This study investigates the influence of obesity on the severity of migraine in children. One hundred and twenty-four patients (77 female, 36 with aura; mean age 12.9 ± 2.8 years; age range 4.0–17.0 years) were included. Headache features such as number and duration of attacks, pain severity and associated symptoms were compared between obese, overweight and normal weight patients. The percentage of obesity was 17.7. Although pain severity and duration were not different among groups, obese patients had more frequent attacks than the overweight and normal weight patients (5.3 ± 2.4, 4.4 ± 2.4 and 3.8 ± 2.4 attacks/month, respectively, P = 0.018). There was also a positive correlation between relative body mass index and number of attacks ( P = 0.026, r = 0.20). Obesity did not have an influence on migraine-associated symptoms including aura, phono/photophobia, nausea and vomiting. In this study, obesity appeared to be related to the frequency of headache attacks in children and adolescents with migraine.

Increased risk for coeliac disease in paediatric patients with migraine

The aim was to determine the prevalence of coeliac disease (CD) in paediatric patients with migraine. Serum tissue transglutaminase IgA (tTGA) antibodies and IgA concentrations were measured in 73 patients with migraine (age range 6-17 years) and the control group (n = 147). Patients having positive tTGA antibodies underwent duodenal biopsy. Four patients (5.5%) from the study group and one (0.6%) from the control group had positive tTGA antibody titres (P < 0.05). Three patients with migraine had normal duodenal histology and were considered as potential CD. One patient from the study group and one from the control group declined to have biopsy. tTGA antibody is considered as a reliable indicator for the presence of CD. However, some patients with positive antibodies may have normal biopsy initially and are classified as having potential CD. Our finding of a higher prevalance of tTGA antibodies in paediatric migraine patients suggests that an association between migraine and CD might exist.

Clinical and radiologic correlates of frontal intermittent rhythmic delta activity

To assess the clinical and radiologic correlates of frontal intermittent rhythmic delta activity (FIRDA), the authors reviewed the hospital charts of patients whose EEGs depicted this EEG finding, and recorded their past medical and neurologic history, the reason for hospital admission, and their neurologic status both on admission and during EEG recordings. Laboratory results on admission and concomitant to the EEG recording, computed tomography, or MRI findings during hospital admission were also reviewed. Sixty-eight patients were assessed. The gender ratio was 1:1; mean age was 56 years. Chronic disease occurred in 78% of patients, including hypertension (34%), diabetes (32%), and renal failure (18%). On admission, renal failure (n = 34) and hyperglycemia (n = 22) were most prominent. The majority of patients had at least one abnormal laboratory result. Thirty-eight of 51 patients in whom the level of consciousness was stated during EEG were described as awake. More than half of 58 patients whose EEG background activity was stipulated demonstrated diffuse slowing, mostly in the theta range. MRI was abnormal in 15 of 17 patients. Intrahemispheric lesions, particularly ischemic and hemorrhagic, were most common (n = 10), followed by basal ganglia lacunae (n = 4). Computed tomography was abnormal in 29 of 44 patients. Hemispheric pathology, diffuse or localized, occurred in 22 patients. Frontal intermittent rhythmic delta activity is associated with mild to moderate encephalopathy and is detected principally in awake patients. Most patients in this series had chronic systemic illness. Old ischemic structural brain lesions may predispose some patients to develop FIRDA during acute metabolic derangement, such as uremia and hyperglycemia. Frontal intermittent rhythmic delta activity was not associated with EEG epileptiform activity. Deep midline lesions, posterior fossa tumors, and hydrocephalus were not detected in this series of patients with FIRDA.

Activated protein C resistance and false type 2 protein C deficiency detected after multiple shunt failures in a patient with hydrocephalus

A 2-year-old hydrocephalic boy who had suffered multiple shunt failures was evaluated for hypercoagulability after a thrombus was removed from his right atrium. The work-up revealed that the patient had the heterozygous form of activated protein C resistance and false type 2 protein C deficiency by the clotting method. His protein C activity was normal by the chromogenic method. We suggest that patients having hydrocephalus, shunt-associated thrombus formation, or both should be evaluated for thrombophilic disorders, and protein C activity should be measured by chromogenic assay in patients with documented activated protein C resistance.

Echocardiographic assessment of left and right ventricular diastolic functions in children with dilated cardiomyopathy

We evaluated left and right ventricular diastolic functions by pulsed Doppler echocardiography in 16 children with dilated cardiomyopathy and in 20 healthy age-matched control subjects. The cardiomyopathy group demonstrated an abnormal relaxation pattern of the left ventricle. In the cardiomyopathy group compared to normal subjects, peak early filling velocities (43.3 +/- 11 cm/s versus 60.4 +/- 11 cms/s, p < 0.01), the corresponding velocity-time integrals (3.3 +/- 1.4 cm versus 4.6 +/- 1.2 cm, p < 0.01) and the ratio of peak early filling velocity to late filling velocity (1.22 +/- 0.47 versus 1.49 +/- 0.23, p < 0.05) were significantly lower whereas isovolumic relaxation time was significantly longer (58.9 +/- 19.8 ms versus 49.7 +/- 8.9 ms, p < 0.05). In addition, right ventricular diastolic filling was also impaired in children with dilated cardiomyopathy. Peak early filling velocities (41 +/- 7.9 cm/s versus 47.5 +/- 8.8 cm/s, p < 0.05) and the corresponding velocity time integrals (3.0 +/- 1.0 cm versus 3.87 +/- 1.1 cm, p < 0.05) were significantly decreased, while isovolumic relaxation time was significantly increased (60.6 +/- 16.3 ms versus 52.2 +/- 12.8 ms, p < 0.05) in the cardiomyopathy group. The study suggests that abnormalities of both right and left ventricular diastolic function may occur, and should be searched for, in pediatric patients with dilated cardiomyopathy.