Yield of brain MRI in children with autism spectrum disorder.

Autism spectrum disorder (ASD) is a common neurodevelopmental condition. The American Academy of Paediatrics and American Academy of Neurology do not recommend routine brain magnetic resonance imaging (MRI) in the assessment of ASD. The need for a brain MRI should be decided on atypical features in the clinical history and examination. However, many physicians continue to use brain MRI routinely in the assessment process. We performed a retrospective review of indications for requesting brain MRI in our institution over a 5-year period. The aim was to identify the yield of MRI in children with ASD and calculate the prevalence of significant neuroimaging abnormalities in children with ASD and identify clinical indications for neuroimaging. One hundred eighty-one participants were analysed. An abnormal brain MRI was identified in 7.2% (13/181). Abnormal brain MRI was more likely with an abnormal neurological examination (OR 33.1, p = 0.001) or genetic/metabolic abnormality (OR 20, p = 0.02). In contrast, abnormal MRI was not shown to be more likely in children with a variety of other indications such as behavioural issues and developmental delay.      Conclusion: Thus, our findings support that MRI should not be a routine investigation in ASD, without additional findings. The decision to arrange brain MRI should be made on a case-by-case basis following careful evaluation of potential risks and benefits. The impact of any findings on the management course of the child should be considered prior to arranging imaging. What is Known: • Incidental brain MRI findings are common in children with and without ASD. • Many children with ASD undergo brain MRI in the absence of neurological comorbidities. What is New: • Brain MRI abnormalities in ASD are more likely with an abnormal neurological examination and genetic or metabolic conditions. • Prevalence of significant brain MRI abnormalities in ASD alone is low.

Uniparental disomy screen of Irish rare disorder cohort unmasks homozygous variants of clinical significance in the TMCO1 and PRKRA genes.

A uniparental disomy (UPD) screen using whole genome sequencing (WGS) data from 164 trios with rare disorders in the Irish population was performed to identify large runs of homozygosity of uniparental origin that may harbour deleterious recessive variants. Three instances of whole chromosome uniparental isodisomy (UPiD) were identified: one case of maternal isodisomy of chromosome 1 and two cases of paternal isodisomy of chromosome 2. We identified deleterious homozygous variants on isodisomic chromosomes in two probands: a novel p (Glu59ValfsTer20) variant in TMCO1, and a p (Pro222Leu) variant in PRKRA, respectively. The overall prevalence of whole chromosome UPiD in our cohort was 1 in 55 births, compared to 1 in ∼7,500 births in the general population, suggesting a higher frequency of UPiD in rare disease cohorts. As a distinct mechanism underlying homozygosity compared to biallelic inheritance, the identification of UPiD has important implications for family planning and cascade testing. Our study demonstrates that UPD screening may improve diagnostic yields by prioritising UPiD chromosomes during WGS analysis.

Dystonia in children with acquired brain injury.

AIM: To quantify the proportion of children who develop dystonia after acquired brain injury (ABI) admitted to a tertiary paediatric intensive care unit (PICU) and analyse the trajectory of dystonia over a 6 month period. METHODS: Children's Health Ireland at Temple Street PICU electronic database was searched for key terms related to ABI from January 1, 2016 to March 14, 2021. Individuals meeting inclusion criteria were analysed, and clinical data pertinent to ABI, dystonia, treatment and outcomes were reviewed. RESULTS: Six-hundred and forty-three PICU episodes (580 patients) met search criteria for ABI, with 379 included in the final analysis. Twelve patients developed dystonia following ABI, giving an incidence of 3.2%. The incidence was higher in the hypoxia/anoxia and TBI cohort at 8.3% and 6.2%, respectively. All patients developed dystonia within the first month following ABI (50% by a week). Patients who developed dystonia compared to non-dystonia cohort had a median lower GCS on admission (4.5 versus 7.0, p value 0.032), longer median length of PICU stay (14.0 versus 3.0 days, p value < 0.001) and were older (median age 9.08 versus 4.68 years, p value 0.06). Dystonia persisted in the majority at 6 months (10/11), requiring on-going medical therapies. CONCLUSION: In our retrospective study, the estimated incidence of dystonia following ABI admitted to the PICU was 3.2%, highest in the hypoxia/anoxia (8.3%) and TBI (6.2%) cohorts. Dystonia emerged early and persisted at 6 months in the majority. This is the first review of dystonia, clinical trajectory and outcomes conducted post-PICU admission for ABI. Future prospective studies are required to determine the true prevalence and burden of disease in the PICU setting.

Amnestic Mild Cognitive Impairment is Characterized by the Inability to Recover from Proactive Semantic Interference across Multiple Learning Trials.

BACKGROUND: Difficulties in inhibition and self-monitoring are early features of incipient Alzheimer's disease and may manifest as susceptibility to proactive semantic interference. However, due to limitations of traditional memory assessment paradigms, recovery from interference effects following repeated learning opportunities has not been explored. OBJECTIVE: This study employed a novel computerized list learning test consisting of repeated learning trials to assess recovery from proactive and retroactive semantic interference. DESIGN: The design was cross-sectional. SETTING: Participants were recruited from the community as part of a longitudinal study on normal and abnormal aging. PARTICIPANTS: The sample consisted of 46 cognitively normal individuals and 30 participants with amnestic mild cognitive impairment. MEASUREMENTS: Participants were administered the Cognitive Stress Test and traditional neuropsychological measures. Step-wise logistic regression was applied to determine which Cognitive Stress Test measures best discriminated between diagnostic groups. This was followed by receiver operating characteristic analyses. RESULTS: Cued A3 recall, Cued B3 recall and Cued B2 intrusions were all independent predictors of diagnostic status. The overall predictive utility of the model yielded 75.9% sensitivity, 91.1% specificity, and an overall correct classification rate of 85.1%. When these variables were jointly entered into receiver operating characteristic analyses, the area under the curve was .923 (p<.001). CONCLUSIONS: This novel paradigm's use of repeated learning trials offers a unique opportunity to assess recovery from proactive and retroactive semantic interference. Participants with mild cognitive impairment exhibited a continued failure to recover from proactive interference that could not be explained by mere learning deficits.

Clinical and genetic spectrum of SCN2A-associated episodic ataxia.

BACKGROUND: Pathogenic variants in SCN2A are associated with various neurological disorders including epilepsy, autism spectrum disorder and intellectual disability. Few reports have recently described SCN2A-associated episodic ataxia (EA). Our study identifies its broader clinical and genetic spectrum, and describes pharmacological approaches. RESULTS: We report 21 patients with SCN2A-associated EA, of which 9 are unpublished cases. The large majority of patients present with epileptic seizures (18/21, 86%), often starting within the first three months of life (12/18, 67%). In contrast, onset of episodic ataxia ranged from 10 months to 14 years of age. The frequency of EA episodes ranged from brief, daily events up to 1-2 episodes per year each lasting several weeks. Potential triggers include minor head traumas and sleep deprivation. Cognitive outcome is favorable in most patients with normal or mildly impaired cognitive development in 17/21 patients (81%). No clear genotype-phenotype correlations were identified in this cohort. However, two mutational hotspots were identified, i.e. 7/21 patients (33%) harbor the identical pathogenic variant p.A263V, whereas 5/21 (24%) carry pathogenic variants that affect the S4 segment and its cytoplasmic loop within the domain IV. In addition, we identified six novel pathogenic variants in SCN2A. While acetazolamide was previously reported as beneficial in SCN2A-associated EA in one case, our data show a conflicting response in 8 additional patients treated with acetazolamide: three of them profited from acetazolamide treatment, while 5/8 did not. CONCLUSIONS: Our study describes the heterogeneous clinical spectrum of SCN2A-associated EA, identifies two mutational hotspots and shows positive effects of acetazolamide in about 50%.

Review of the phenotype of early-onset generalised progressive dystonia due to mutations in KMT2B.

In 2016, two research groups independently identified microdeletions and pathogenic variants in the lysine-specific histone methyltransferase 2B gene, KMT2B in patients with early-onset progressive dystonia. KMT2B-dystonia (DYT28) is emerging as an important and frequent cause of childhood-onset progressive generalised dystonia and is estimated to potentially account for up to 10% of early-onset generalised dystonia. Herein, we review variants in KMT2B associated with dystonia, as well as the clinical phenotype, treatment and underlying disease mechanisms. Furthermore, in context of this newly identified condition, we summarise our approach to the genetic investigation of paediatric dystonia.

NAPB - a novel SNARE-associated protein for early-onset epileptic encephalopathy.

Next-generation sequencing has accelerated the identification of disease genes in many rare genetic disorders including early-onset epileptic encephalopathies (EOEEs). While many of these disorders are caused by neuronal channelopathies, the role of synaptic and related neuronal proteins are increasingly being described. Here, we report a 6-year-old girl with unexplained EOEE characterized by multifocal seizures and profound global developmental delay. Recessive inheritance was considered due to parental consanguinity and Irish Traveller descent. Exome sequencing was performed. Variant prioritization identified a homozygous nonsense variant in the N-ethylmaleimide-sensitive factor attachment protein, beta (NAPB) gene resulting in a premature stop codon and 46% loss of the protein. NAPB plays a role in soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE)-complex dissociation and recycling (synaptic vesicle docking). Knockout mouse models of the murine ortholog Napb have been previously reported. These mice develop recurrent post-natal epileptic seizures in the absence of structural brain changes. The identification of a disease-causing variant in NAPB further recognizes the importance of the SNARE complex in the development of epilepsy and suggests that this gene should be considered in patients with unexplained EOEE.

Resistance to spiromesifen in Trialeurodes vaporariorum is associated with a single amino acid replacement in its target enzyme acetyl-coenzyme A carboxylase.

Spiromesifen is a novel insecticide and is classed as a tetronic acid derivative. It targets the insects' acetyl-coenzyme A carboxylase (ACCase) enzyme, causing a reduction in lipid biosynthesis. At the time of this publication, there are no reports of resistance to this class of insecticides in insects although resistance has been observed in several mite species. The greenhouse whitefly Trialeurodes vaporariorum (Westwood) is a serious pest of protected vegetable and ornamental crops in temperate regions of the world and spiromesifen is widely used in its control. Mortality rates of UK and European populations of T. vaporariorum to spiromesifen were calculated and up to 26-fold resistance was found. We therefore sought to examine the molecular mechanism underlying spiromesifen resistance in this important pest. Pre-treatment with piperonyl butoxide did not synergize spiromesifen, suggesting a target-site resistance mechanism. The full length ACCase gene was sequenced for a range of T. vaporariorum strains and a strong association was found between spiromesifen resistance and a glutamic acid substitution with lysine in position 645 (E645K) of this gene. A TaqMan allelic discrimination assay confirmed these findings. Although this resistance is not considered sufficient to compromise the field performance of spiromesifen, this association of E645K with resistance is the first report of a potential target site mechanism affecting an ACCase inhibitor in an arthropod species.

Practical approaches to the treatment of severe pediatric obesity.

Pediatric obesity is a major public health threat. Obese children and adolescents are at increased risk for many medical and surgical conditions. These conditions may affect their quality of life and life expectancy. The rapidly progressive nature of type 2 diabetes mellitus within the first 5 years of obesity diagnosis is particularly concerning. Because health risk increases with degree of obesity, adolescents who may be eligible for more aggressive obesity treatment should be identified and counseled.

Overexpression of a cytochrome P450 monooxygenase, CYP6ER1, is associated with resistance to imidacloprid in the brown planthopper, Nilaparvata lugens.

The brown planthopper, Nilaparvata lugens, is an economically significant pest of rice throughout Asia and has evolved resistance to many insecticides including the neonicotinoid imidacloprid. The resistance of field populations of N. lugens to imidacloprid has been attributed to enhanced detoxification by cytochrome P450 monooxygenases (P450s), although, to date, the causative P450(s) has (have) not been identified. In the present study, biochemical assays using the model substrate 7-ethoxycoumarin showed enhanced P450 activity in several resistant N. lugens field strains when compared with a susceptible reference strain. Thirty three cDNA sequences encoding tentative unique P450s were identified from two recent sequencing projects and by degenerate PCR. The mRNA expression level of 32 of these was examined in susceptible, moderately resistant and highly resistant N. lugens strains using quantitative real-time PCR. A single P450 gene (CYP6ER1) was highly overexpressed in all resistant strains (up to 40-fold) and the level of expression observed in the different N. lugens strains was significantly correlated with the resistance phenotype. These results provide strong evidence for a role of CYP6ER1 in the resistance of N. lugens to imidacloprid.

Analyzing haplodiploid inheritance of insecticide resistance in whitefly biotypes.

We developed new methods for analyzing inheritance of insecticide resistance in haplodiploid arthropods and applied them to elucidate resistance of the whitefly Bemisia tabaci (Gennadius) to an insect growth regulator, pyriproxyfen. Two invasive biotypes of this devastating crop pest, the B biotype in Arizona and the Q biotype in Israel, have evolved resistance to pyriproxyfen. Here, we incorporated data from laboratory bioassays and crossing procedures exploiting haplodiploidy into statistical and analytical models to estimate the number of loci affecting pyriproxyfen resistance in strains of both biotypes. In tests with models of one to ten loci, the best fit between expected and observed mortality occurred with a two-locus model for the B biotype strain (QC-02) and for one- and two-locus models for the Q biotype strain (Pyri-R). The estimated minimum number of loci affecting resistance was 1.6 for the B biotype strain and 1.0 for the Q biotype strain. The methods used here can be applied to insecticide resistance and other traits in haplodiploid arthropods.

A series of monozygotic twins discordant for ovarian failure: ovary transplantation (cortical versus microvascular) and cryopreservation.

BACKGROUND: A series of monozygotic (MZ) twin pairs discordant for premature ovarian failure presented an unusual opportunity to study ovarian transplantation. METHODS: Ten MZ twin pairs requested ovarian transplantation and eight have undergone transplantation with cryopreservation of spare tissue. Seven had a fresh cortical tissue transplant, one of whom received a second frozen-thawed transplant after the first ceased functioning at three years. One had a fresh microvascular transplant. RESULTS: All recipients reinitiated ovulatory menstrual cycles and normal Day 3 serum FSH levels by 77-142 days. Six have already conceived naturally (one twice). Currently, two healthy babies have been delivered, and another three pregnancies are ongoing. The oldest transplant functioned for 36 months, resulting in one child and one miscarriage. She conceived again after a frozen-thawed secondary transplant. There was no apparent difference in return of ovarian function between the eight fresh ovarian grafts and the one frozen graft. CONCLUSIONS: Ovarian transplantation appears to restore ovulatory function robustly. Successful pregnancies, including one after cryopreservation, bode well for application to fertility preservation.

Biotype status and genetic polymorphism of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) in Greece: mitochondrial DNA and microsatellites.

The genetic polymorphism and the biotype identity of the tobacco whitefly Bemisia tabaci (Gennadius) have been studied in population samples taken from different localities within Greece from cultivated plants growing in greenhouses or in open environments and from non-cultivated plants. Two different approaches were used: sequencing of the mitochondrial cytochrome oxidase I (mtCOI) gene and genotyping using microsatellite markers. Analyses of the mtCOI sequences revealed a high homogeneity between the Greek samples which clustered together with Q biotype samples that had been collected from other countries. When genetic polymorphism was examined using six microsatellite markers, the Greek samples, which were all characterized as Q biotype were significantly differentiated from each other and clustered into at least two distinct genetic populations. Moreover, based on the fixed differences revealed by the mtCOI comparison of known B. tabaci biotype sequences, two diagnostic tests for discriminating between Q and B and non-Q/non-B biotypes were developed. Implementation of these diagnostic tools allowed an absence of the B biotype and presence of the Q biotype in the Greek samples to be determined.

Correlated evolution of maternally derived yolk testosterone and early developmental traits in passerine birds.

Recent studies on hormone-mediated maternal effects in birds have highlighted the influence of variable maternal yolk androgen concentration on offspring phenotype, particularly in terms of early development. If genetic differences between laying females regulate variation in yolk hormone concentration, then this physiological maternal effect is an indirect genetic effect which can provide a basis for the co-evolution of maternal and offspring phenotypes. Thus, we investigated the evolutionary associations between maternally derived yolk testosterone (T) and early developmental traits in passerine birds via a comparative, phylogenetic analysis. Our results from species-correlation and independent contrasts analyses provide convergent evidence for the correlated evolution of maternal yolk T concentration and length of the prenatal developmental period in passerines. Here, we show these traits are significantly negatively associated (species-correlation: p<0.001, r2=0.85; independent contrasts: p=0.005). Our results highlight the need for more studies investigating the role of yolk hormones in evolutionary processes concerning maternal effects.

Differential patterns of development: the interaction of birth weight, temperament, and maternal behavior.

A short-term longitudinal study of 83 families compared patterns of development between full-term small for gestational age (SGA) and normal birth weight (NBW) infants. Data were collected on infant temperament and maternal interaction at 3 and 6 months, and infant developmental outcomes at 6 months in order to investigate relationships between infant and maternal behavior, and developmental outcomes as a function of birth weight. Findings revealed few differences between SGA and NBW groups. However, the relations between infant temperament and maternal behavior varied as a function of birth weight and home environment. Specifically, more positive home environments were associated with higher ratings of maternal behavior and lower levels of infant negative reactivity for SGA but not for NBW infants. In addition, higher negative reactivity was related to lower performance on both the mental and psychomotor scales of the Bayley Scales of Infant Development (BSID), with stronger associations reported for SGA infants than for NBW infants.

Ethnicity, Sleep Hygiene Knowledge, and Sleep Hygiene Practices.

We tested the mean differences in scores on Sleep Hygiene Knowledge and on Sleep Hygiene Practices among four ethnic groups of university students (N = 963). We computed significant main effects for ethnicity for both of these variables. Primarily the results reflect that the Euro-American students scored significantly higher on both scales than each of the other three groups.