Associations of prenatal mercury exposure from maternal fish consumption and polyunsaturated fatty acids with child neurodevelopment: a prospective cohort study in Italy

BACKGROUND

Mercury is a neurotoxin, and limited prenatal exposure to it can affect long-term child neurodevelopment. However, results of epidemiologic studies of such exposure have been inconsistent. We examined the association of prenatal mercury exposure from maternal fish consumption with child neurodevelopment in northern Italy.

METHODS

A population-based cohort of 606 children and their mothers was studied from pregnancy to age 18 months. Mercury levels were measured in maternal hair and blood during pregnancy and in umbilical cord blood and breast milk. Levels of polyunsaturated fatty acids (PUFAs) were measured in maternal serum. Maternal and child intakes of fish were assessed by using a food frequency questionnaire. The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) was used to evaluate child neurodevelopment. Multivariate linear regression was used to examine the association of mercury exposure with BSID-III scores, after controlling for maternal fish intake, PUFAs during pregnancy, and several other confounders.

RESULTS

Mean weekly fish intake during pregnancy was less than 2 servings. Mercury concentrations in biological samples were low (mean, 1061 ng/g in hair) and moderately correlated with fish intake, particularly of carnivorous species. Maternal ω-3 PUFA concentrations were poorly correlated with fish intake. Maternal intelligence quotient (IQ) and child intake of fish were significantly associated with neurodevelopment scores. In multivariate models, the level of Hg exposure was not associated with neurodevelopmental performance at 18 months.

CONCLUSIONS

In this Italian population, neurodevelopment at 18 months was associated with child intake of fresh fish and maternal IQ rather than with mercury exposure. The expected beneficial effect of maternal fish intake (from maternal ω-3 PUFAs) was not found.

PMM2-CDG: phenotype and genotype in four affected family members

Congenital disorders of glycosylation (CDG) are genetic defects in protein and lipid glycosylation. PMM2-CDG is the most prevalent protein N-glycosylation disorder with more than 700 reported patients. Here we report on a large Italian family with four affected members and three mutations. Two young sisters are compound heterozygous for mutations p.Leu32Arg and p.Arg141His, while two paternal great-aunts are compound heterozygosity for p.Leu32Arg and p.Thr237Met. The latter association has not been reported before. The most severely affected member had in addition an ALG6 mutation known to exacerbate the phenotype of patients with PMM2-CDG.

[Interrater reliability of the Bayley III test in the Italian Northern-Adriatic Cohort II]

OBJECTIVE

to assess the agreement between two trained psychologists who administered the Bayley Scale of Infant Development III (BSID III) to detect neurodevelopment deficits in a cohort of children within the Northern Adriatic Cohort II (NAC II) longitudinal study, which aims to assess the impact of mercury exposure through food consumption of mothers in pregnancy on their children's neurodevelopment.

DESIGN

a reliability study was carried out. Two trained psychologists administered the test, each one scoring the test independently, and serving as the primary examiner for half of the sample and as the observer for the other half.

SETTING AND PARTICIPANTS

a sample of 53 children of 18 months of age was enrolled consecutively within the Italian NAC II, and tested using the Bayley Scale of Infant Development III (BSID III) to detect neurodevelopment deficits.

MAIN OUTCOME MEASURES

the cognitive, language, and motor scales of the BSID III were evaluated and the respective Intraclass Correlation Coefficients (ICC) were calculated.

RESULTS

overall, the ICCs for the cognitive and language scales were very high (≥0.98), while the ICCs for the motor scales were slightly lower, ranging from 0.86 (gross motor, scaled) to 0.97 (fine motor, scaled), but still higher than 0.80, reported as the general acceptable benchmark for psychological testing.

CONCLUSION

the interrater reliability of all BSID III scales for this sample of 18-month-old children is very high and assures comparable results between the two psychologists involved in the Italian NAC II study. The reasons are a common training, the joint evaluation of many children during the preliminary phase of the study, the discussion of inconsistent results, but also the "go no-go" nature of the items in BSID III.

The submerged dyslexia iceberg: how many school children are not diagnosed? Results from an Italian study

BACKGROUND

Although dyslexia is one of the most common neurobehavioral disorders affecting children, prevalence is uncertain and available data are scanty and dated. The objective of this study is to evaluate the prevalence of dyslexia in an unselected school population using clearly defined and rigorous diagnostic criteria and methods.

METHODS

Cross sectional study. We selected a random cluster sample of 94 fourth grade elementary school classes of Friuli Venezia Giulia, a Region of North Eastern Italy. We carried out three consecutive levels of screening: the first two at school and the last at the Neuropsychiatry Unit of a third level Mother and Child Hospital. The main outcome measure was the prevalence of dyslexia, defined as the number of children positive to the third level of screening divided by the total number of children enrolled.

RESULTS

We recruited 1774 children aged 8-10 years, of which 1528 received parents' consent to participate. After applying exclusion criteria, 1357 pupils constituted the final working sample. The prevalence of dyslexia in the enrolled population ranged from 3.1% (95% CI 2.2-4.1%) to 3.2% (95% CI 2.4-4.3%) depending on different criteria adopted. In two out of three children with dyslexia the disorder had not been previously diagnosed.

CONCLUSIONS

This study shows that dyslexia is largely underestimated in Italy and underlines the need for reliable information on prevalence, in order to better allocate resources both to Health Services and Schools.

Extra-large letter spacing improves reading in dyslexia

Although the causes of dyslexia are still debated, all researchers agree that the main challenge is to find ways that allow a child with dyslexia to read more words in less time, because reading more is undisputedly the most efficient intervention for dyslexia. Sophisticated training programs exist, but they typically target the component skills of reading, such as phonological awareness. After the component skills have improved, the main challenge remains (that is, reading deficits must be treated by reading more--a vicious circle for a dyslexic child). Here, we show that a simple manipulation of letter spacing substantially improved text reading performance on the fly (without any training) in a large, unselected sample of Italian and French dyslexic children. Extra-large letter spacing helps reading, because dyslexics are abnormally affected by crowding, a perceptual phenomenon with detrimental effects on letter recognition that is modulated by the spacing between letters. Extra-large letter spacing may help to break the vicious circle by rendering the reading material more easily accessible.

Neuromotor deficits in developmental coordination disorder: evidence from a reach-to-grasp task

Developmental coordination disorder (DCD) has been classified as a specific learning disability, nonetheless the underlying cognitive mechanisms are still a matter of discussion. After a summary of the main hypotheses on the principal neuromotor causes of DCD, this study applies a causal model framework to describe the possible coexistence of more than one deficit in this disorder. For this purpose, kinematic analysis was applied to an ecological task, the reach-to-grasp action, introducing the manipulation of three variables: vision, distance and object size. After a thorough neurological and neuropsychological evaluation, 9 children with DCD (7-9 years old) were selected and compared to 27 age-matched control children. The results suggest that children with DCD have a normal neurological characterization of the reaching and grasping movements, in terms of proximal to distal action, but their grasping aperture (MGA) was always wider with respect to controls, particularly when vision was not allowed. In addition, the performance of children with DCD was always slower, more dependent on vision and more variable than that of controls. The MGA of children with DCD could be explained by a deficit in the internal construction of movement for a forward model, while slowness could be related to a control problem in the neuronal firing of the muscles. The idea of a possible coexistence of these two deficits is discussed in accordance to a causal model framework and also addressed considering recent neurophysiologic evidences.

The Tolosa-Hunt Syndrome in Children: A Case Report

Tolosa-Hunt syndrome (THS) is characterized by unilateral painful ophthalmoplegia with oculomotor paresis, associated with an idiopathic granulomatous inflammation involving the cavernous sinus, with a typical relapsing-remitting course. We report a case of an 8-year-old girl who was admitted because of an ophthalmoplegia with exotropia and ptosis of the left eyelid, accompanied by diplopia and left sovraorbital pain. The clinical data, neuroradiological findings and response to steroid treatment suggested THS, as defined by the 2004 International Classification of Headache Disorders (ICHD)-II criteria. THS must be considered a possible cause of painful ophthalmoplegia in childhood, as well as in adults, and confirmed with a focused neuroradiological investigation. The few paediatric cases described in the literature that meet the 2004 ICHD-II criteria are not sufficient to identify possible differences between the paediatric and the adult forms. Every new paediatric case should therefore be reported in order to gather and compare further information.

Trisomy 12p and monosomy 4p: phenotype-genotype correlation

4p Monosomy and 12p trisomy have been discussed and redefined along with recently reviewed chromosomal syndromes. 12p Trisomy syndrome is characterized by normal or increased birth weight, developmental delay with early hypotonia, psychomotor delay, and typical facial appearance. Most likely, the observed phenotypic variability depends on the type and extent of the associated partial monosomy. Partial deletions of the short arm of one chromosome 4 cause the Wolf-Hirschhorn syndrome (WHS). Affected patients present Greek helmet face, growth and mental retardation, hypotonia, and seizures. The combination of these characteristics constitutes the phenotypic core of WHS. We present a clinical and molecular cytogenetic characterization of a 4-year old mentally retarded girl with macrosomy, facial dysmorphisms, and epilepsy, in whom an unbalanced t(4;12)(p16.3;p13.3) translocation was detected, giving rise to partial 4p monosomy and partial 12p trisomy. Because the patient shows most of the phenotypic characteristics of 12p trisomy, this case could contribute to a better definition of the duplicate critical region that determines the phenotype of the 12p trisomy syndrome.

Two novel POLG mutations causing hepatic mitochondrial DNA depletion with recurrent hypoketotic hypoglycaemia and fatal liver dysfunction

BACKGROUND

Inherited mtDNA depletion syndromes (MDS) are a group of severe mitochondrial disorders resulting from defects in nucleus-encoded factors and often associated with severe or fatal liver failure.

PATIENT

In this article, we describe the case of an 18-month-old patient with recurrent hypoketotic hypoglycaemia and fatal hepatic dysfunction with liver mtDNA depletion.

METHODS

The assessment of mtDNA copy number was performed on leucocytes, liver and muscle biopsy by Quantitative Real Time PCR and total RNA from liver biopsy was used as a template to amplify the cDNA of the POLG1 gene.

RESULTS

Sequence analysis identified two previously undescribed mutations (1868T>G and 2263A>G) located in the gene coding the catalytic subunit of mitochondrial DNA polymerase gamma (POLG), predicting an L623W and K755E amino acid change, respectively. Both mutations were located in the highly conserved linker region of the protein and were absent in more than 200 healthy unrelated control subjects. The identification of these two mutations allowed us to perform genetic counselling and prenatal diagnosis.

CONCLUSION

Our data further expand the spectrum of POLG1 gene mutations and the unique phenotype reported (late onset isolated liver disease without lactic acidosis) increase the variability of clinical presentations associated with mutations in this gene.

1q44-qter trisomy: clinical report and review of the literature

Subtelomeric rearrangements are one of the main causes of multiple congenital anomalies and mental retardation, and they are detected in 5% of patients. We report on a 6.5-year-old boy with mental retardation, dysmorphic features, and behavioral problems, who revealed 1q44-qter trisomy and 22q13.3-qter monosomy due to a maternal cryptic translocation t(1;22). We compared the clinical and cytogenetic data of our patient with those of another case presenting a pure 22qter monosomy and with those of all 1qter trisomy cases reported in the international literature. To the best of our knowledge, the subterminal 1q trisomy found in the present case has been reported in only 12 patients to date (including five familial cases). This report aims to contribute to our understanding of 1q44-qter trisomy.

Carbamazepine hypersensitivity syndrome triggered by a human herpes virus reactivation in a genetically predisposed patient

A case of severe hypersensitivity syndrome, triggered by carbamazepine in the presence of a concomitant active human herpes virus (HHV) 6 and 7 infection is described. To further understand the molecular mechanism of this adverse reaction, analyses of the genetic variants of human leukocyte antigen (HLA) and of the epoxide hydrolase gene (EPHX1), previously associated with carbamazepine hypersensitivity, were performed. A lymphocyte transformation test (LTT) was conducted in order to detect drug-specific lymphocytes. In the hypersensitive patient, 2 genetic factors previously associated with intolerance to carbamazepine were detected: the allele HLA-A*3101 and homozygosity for the variant allele of SNP rs1051740 in EPHX1. Drug-specific lymphocytes could be detected by LTT when the HHV was active (positive PCR for viral DNA and increased anti-HHV 6 IgG titer), but not when it was no longer active. In conclusion, we document a case of severe carbamazepine hypersensitivity triggered by viral reactivation in a patient presenting the interaction of 2 unfavorable genetic factors.

Chronic tension-type headache in adolescents. Clinical and psychological characteristics analyzed through self- and parent-report questionnaires

OBJECTIVES

To analyze the relation between the symptoms reported by adolescents with chronic tension-type headache (CTTH) and their perception of their emotional and behavioral functioning.

METHODS

Two groups of adolescents (clinical group, n = 48; control group, n = 135) and their parents (clinical group, n = 42; control group, n = 128) were studied, respectively, with the Youth Self-Report Questionnaire and the Child Behavior Checklist. Moreover, a secondary analysis was performed, identifying another subgroup of adolescents who reported having headaches.

RESULTS

The clinical group of adolescents obtained higher scores than the control group in Internalizing Syndrome; Aggressive Behavior for Externalizing Syndrome; Social, Thought, and Attention Problems; and in all Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV)-oriented scales (except conduct problems). Differences between the two groups of parents were found in all the scales. The controls reporting headaches obtained interesting intermediate scores.

CONCLUSIONS

Adolescents with CTTH show greater emotional and behavioral problems than their healthy peers. Consequently, clinical approaches for proper diagnosis and treatment need to adopt a multidisciplinary prospective.

Comorbidity of DCD and SLI: Significance of epileptiform activity during sleep

BACKGROUND

In children affected by specific language impairment (SLI), many authors have investigated a link between language and epileptiform discharges during sleep resembling the focal sharp waves typical of benign epilepsy with centro-temporal spikes (BECTS), the so-called rolandic spikes. On the other hand, the same electroencephalographic trait occurs in more than 50% of children affected by learning or behavioural disabilities without seizures, supporting the hypothesis of a common genetic disposition. The biological background of Developmental Coordination Disorder (DCD) is currently unknown, but a genetic liability may be assumed. The aims of our study were first to estimate the prevalence of sleep-related epileptiform discharges in children affected by DCD and second to investigate the occurrence of DCD in a population of children affected by BECTS.

METHODS

We selected a group of eight children with severe DCD. In this group, the presence of epileptiform activity was investigated. We also searched for DCD among a group of 13 children affected by BECTS.

RESULTS

We found rolandic spikes in more than 70% of the children with severe DCD and severe DCD in more than 30% of the children with BECTS.

CONCLUSIONS

In children with severe DCD other disabilities are frequently associated. In these children, epileptiform activity during sleep is very frequently found and in our opinion, this represents a hallmark of 'Hereditary Impairment of Brain Maturation', a term only partially resembling 'Atypical Brain Development'.

A Comparison of the Reach-To-Grasp Movement Between Children and Adults: A Kinematic Study

In this study, the reach-to-grasp movement of 5-year-old children was compared to that of adults. Participants were required to reach out and grasp objects, with and without on-line visual feedback. Object size and distance were covaried in a within-subjects design and it was found that for both groups, grip formation and reach kinematics were affected by the manipulation of either variable. Although there are a large number of similarities, a few differences between the two groups emerge. For the reaching component, the children revealed a longer movement duration and deceleration time and a lower maximum height of wrist trajectory than in adults. For the grasp component, the children, in both the vision and no-vision condition, show a maximal finger aperture larger than the adults. Further, the children of this study were able to scale their grip aperture according to object size when visual feedback during the movement was lacking. These findings suggest that children adopt different strategies than adults when planning a reach-to-grasp movement on the basis of object size, distance, and the predictability of visual feedback. The results are discussed in terms of the neural mechanisms underlying hand action and how these mechanisms may not be fully developed by the age of 5.

Analysis of Sleep-Stage Characteristics in Full-Term Newborns by Means of Spectral and Fractal Parameters

STUDY OBJECTIVES

In this work, we studied the behavior of the fractal dimension during each of the neonatal electroencephalogram (EEG) sleep phases and during the awake state, comparing the results with those of the classical spectral parameters and with zero crossing values.

DESIGN

Fractal dimension, zero crossing, and spectral parameters of the EEG bands were determined for each 2-second frame of the EEG sleep-time series. Eight channels of each EEG recording were examined.

PARTICIPANTS

Twenty healthy full-term newborns (10 boys and 10 girls) with normal psychomotor development evaluated at 24 and 36 months of age, were chosen to participate in this study.

MEASUREMENTS AND RESULTS

Fractal analysis showed that where rhythmic and regular activity are present, as during quiet sleep, the fractal dimension is low and rises when bioelectric activity is more variable and complex, reaching its maximum value during wakefulness. The discriminative value of this parameter was similar to that of some spectral bands.

CONCLUSIONS

This work was an initial attempt to apply techniques derived from the nonlinear deterministic studies used to evaluate system complexity, to the neonatal EEG, in order to acquire a normative database that can be used as a reference in neurological pathologies. Fractal dimension alone or together with zero crossing and theta and delta bands could be used for computerized discrimination of neonatal EEG sleep phases.

Supernumerary ring chromosome 8: Clinical and molecular cytogenetic characterization in a case report

We report on a 3-year-old male with developmental delay, autistic behavior, and minor abnormalities consistent with trisomy 8 syndrome whose cytogenetic analysis revealed mosaicism for a supernumerary ring chromosome (SRC). Fluorescence in situ hybridization (FISH) studies, using centromeric and yeast artificial chromosome (YAC) probes, were performed to characterize further the supernumerary chromosome. The ring origin has been detected from the short arm of chromosome 8, resulting in r(8)(p10p23.1). Moreover, uniparental disomy (UPD) using microsatellite analysis was excluded. To our knowledge a total of 25 cases, confirmed by FISH, have been reported with either supernumerary marker or ring chromosome 8. We present a detailed clinical and molecular cytogenetic characterization of this additional case in order to better define the genotype-phenotype correlation.

Gaucher's disease with Parkinson's disease: clinical and pathological aspects

The association between type 1 Gaucher disease and PD has been reported in the literature. The clinical picture is characterized by the predominance of bilateral akinetic-rigid signs and poor response to levodopa therapy. The authors describe four patients (two siblings) with type 1 Gaucher disease presenting with the following signs of typical PD: asymmetric onset of rigidity, resting tremor, bradykinesia, and a favorable response to Parkinson therapies.

Use of the fractal dimension for the analysis of electroencephalographic time series

Electroencephalogram (EEG) traces corresponding to different physiopathological conditions can be characterized by their fractal dimension, which is a measure of the signal complexity. Generally this dimension is evaluated in the phase space by means of the attractor dimension or other correlated parameters. Nevertheless, to obtain reliable values, long duration intervals are needed and consequently only long-term events can be analysed; also much calculation time is required. To analyse events of brief duration in real-time mode and to apply the results obtained directly in the time domain, thus providing an easier interpretation of fractal dimension behaviour, in this work we optimize and propose a new method for evaluating the fractal dimension. Moreover, we study the robustness of this evaluation in the presence of white or line noises and compare the results with those obtained with conventional spectral methods. The non-linear analysis carried out allows us to investigate relevant EEG events shorter than those detectable by means of other linear and non-linear techniques, thus achieving a better temporal resolution. An interesting link between the spectral distribution and the fractal dimension value is also pointed out.

Endozepine stupor in children

Recurring episodes of stupor in adults have been shown to be related to increased levels of endozepines, which are endogenous ligands for the GABAA receptors. We report here two children presenting with recurrent episodes of stupor associated with fast EEG activity who had increased levels of endozepine-4 in plasma. Mass spectroscopy did not reveal commercially available benzodiazepines. Interictal endozepine-4 levels were normal. In one of the patients, administration of flumazenil (0.25 mg i.v.), a benzodiazepine inverse agonist, induced improvement of consciousness and attenuation of EEG fast activity. In conclusion, children presenting with recurrent episodes of stupor and EEG fast activity should be evaluated for endozepine levels and can be effectively treated with i.v. flumazenil.