Gene-environment interactions: Epstein-Barr virus infection and risk of pediatric-onset multiple sclerosis.

BACKGROUND AND OBJECTIVE: Prior Epstein-Barr virus (EBV) infection is associated with an increased risk of pediatric-onset multiple sclerosis (POMS) and adult-onset multiple sclerosis (MS). It has been challenging to elucidate the biological mechanisms underlying this association. We examined the interactions between candidate human leukocyte antigen (HLA) and non-HLA variants and childhood EBV infection as it may provide mechanistic insights into EBV-associated MS. METHODS: Cases and controls were enrolled in the Environmental and Genetic Risk Factors for Pediatric MS study of the US Network of Pediatric MS Centers. Participants were categorized as seropositive and seronegative for EBV-viral capsid antigen (VCA). The association between prior EBV infection and having POMS was estimated with logistic regression. Interactions between EBV serostatus, major HLA MS risk factors, and non-HLA POMS risk variants associated with response to EBV infection were also evaluated with logistic regression. Models were adjusted for sex, age, genetic ancestry, and the mother's education. Additive interactions were calculated using relative risk due to interaction (RERI) and attributable proportions (APs). RESULTS: A total of 473 POMS cases and 702 controls contributed to the analyses. Anti-VCA seropositivity was significantly higher in POMS cases compared to controls (94.6% vs 60.7%, p < 0.001). There was evidence for additive interaction between childhood EBV infection and the presence of the HLA-DRB1*15 allele (RERI = 10.25, 95% confidence interval (CI) = 3.78 to 16.72; AP = 0.61, 95% CI = 0.47 to 0.75). There was evidence for multiplicative interaction (p < 0.05) between childhood EBV infection and the presence of DRB1*15 alleles (odds ratio (OR) = 3.43, 95% CI = 1.06 to 11.07). Among the pediatric MS variants also associated with EBV infection, we detected evidence for additive interaction (p = 0.02) between prior EBV infection and the presence of the GG genotype in risk variant (rs2255214) within CD86 (AP = 0.30, 95% CI = 0.03 to 0.58). CONCLUSION: We report evidence for interactions between childhood EBV infection and DRB1*15 and the GG genotype of CD86 POMS risk variant. Our results suggest an important role of antigen-presenting cells (APCs) in EBV-associated POMS risk.

Gene-environment interactions increase the risk of paediatric-onset multiple sclerosis associated with household chemical exposures.

BACKGROUND: We previously reported an association between household chemical exposures and an increased risk of paediatric-onset multiple sclerosis. METHODS: Using a case-control paediatric multiple sclerosis study, gene-environment interaction between exposure to household chemicals and genotypes for risk of paediatric-onset multiple sclerosis was estimated.Genetic risk factors of interest included the two major HLA multiple sclerosis risk factors, the presence of DRB1*15 and the absence of A*02, and multiple sclerosis risk variants within the metabolic pathways of common household toxic chemicals, including IL-6 (rs2069852), BCL-2 (rs2187163) and NFKB1 (rs7665090). RESULTS: 490 paediatric-onset multiple sclerosis cases and 716 controls were included in the analyses. Exposures to insect repellent for ticks or mosquitos (OR 1.47, 95% CI 1.06 to 2.04, p=0.019), weed control products (OR 2.15, 95% CI 1.51 to 3.07, p<0.001) and plant/tree insect or disease control products (OR 3.25, 95% CI 1.92 to 5.49, p<0.001) were associated with increased odds of paediatric-onset multiple sclerosis. There was significant additive interaction between exposure to weed control products and NFKB1 SNP GG (attributable proportions (AP) 0.48, 95% CI 0.10 to 0.87), and exposure to plant or disease control products and absence of HLA-A*02 (AP 0.56; 95% CI 0.03 to 1.08). There was a multiplicative interaction between exposure to weed control products and NFKB1 SNP GG genotype (OR 2.30, 95% CI 1.00 to 5.30) but not for other exposures and risk variants. No interactions were found with IL-6 and BCL-2 SNP GG genotypes. CONCLUSIONS: The presence of gene-environment interactions with household toxins supports their possible causal role in paediatric-onset multiple sclerosis.

The Pediatric Optic Neuritis Prospective Outcomes Study: Two-Year Results.

PURPOSE: Pediatric optic neuritis (ON) is a rare disease that has not been well characterized. The Pediatric ON Prospective Outcomes Study (PON1) was the first prospective study to our knowledge aiming to evaluate visual acuity (VA) outcomes, including VA, recurrence risk, and final diagnosis 2 years after enrollment. DESIGN: Nonrandomized observational study at 23 pediatric ophthalmology or neuro-ophthalmology clinics in the United States and Canada. PARTICIPANTS: A total of 28 (64%) of 44 children initially enrolled in PON1 (age 3-<16 years) who completed their 2-year study visit. METHODS: Participants were treated at the investigator's discretion. MAIN OUTCOMES MEASURES: Age-normal monocular high-contrast VA (HCVA). Secondary outcomes included low-contrast VA (LCVA), neuroimaging findings, and final diagnoses. RESULTS: A total of 28 participants completed the 2-year outcome with a median enrollment age of 10.3 years (range, 5-15); 46% were female, and 68% had unilateral ON at presentation. Final 2-year diagnoses included isolated ON (n = 11, 39%), myelin oligodendrocyte glycoprotein-associated demyelination (n = 8, 29%), multiple sclerosis (MS) (n = 4,14%), neuromyelitis optica spectrum disease (NMOSD) (n = 3, 11%), and acute disseminated encephalomyelitis (n = 2, 7%). Two participants (7%; 95% confidence interval [CI], 1-24) had subsequent recurrent ON (plus 1 participant who did not complete the 2-year visit); all had MS. Two other participants (7%) had a new episode in their unaffected eye. Mean presenting HCVA was 0.81 logarithm of the minimum angle of resolution (logMAR) (∼20/125), improving to 0.14 logMAR (∼20/25-2) at 6 months, 0.12 logMAR (∼20/25-2) at 1 year, and 0.11 logMAR (20/25-1) at 2 years (95% CI, -0.08 to 0.3 [20/20+1-20/40-1]). Twenty-four participants (79%) had age-normal VA at 2 years (95% CI, 60-90); 21 participants (66%) had 20/20 vision or better. The 6 participants without age-normal VA had 2-year diagnoses of NMOSD (n = 2 participants, 3 eyes), MS (n = 2 participants, 2 eyes), and isolated ON (n = 2 participants, 3 eyes). Mean presenting LCVA was 1.45 logMAR (∼20/500-2), improving to 0.78 logMAR (∼20/125+2) at 6 months, 0.69 logMAR (∼20/100+1) at 1 year, and 0.68 logMAR (∼20/100+2) at 2 years (95% CI, 0.48-0.88 [20/50+1-20/150-1]). CONCLUSIONS: Despite poor VA at presentation, most children had marked improvement in VA by 6 months that was maintained over 2 years. Associated neurologic autoimmune diagnoses were common. Additional episodes of ON occurred in 5 (18%) of the participants (3 relapses and 2 new episodes).

Association Between Children With Life-Threatening Conditions and Their Parents' and Siblings' Mental and Physical Health.

Importance: Despite concerns regarding the potential deleterious physical and mental health outcomes among family members of a child with a life-threatening condition (LTC), few studies have examined empirical measures of health outcomes among these family members. Objectives: To examine whether mothers, fathers, sisters, and brothers of children with 1 of 4 types of pediatric LTCs have higher rates of health care encounters, diagnoses, and prescriptions compared with families of children without these conditions. Design, Setting, and Participants: This retrospective cohort study included US families with commercial insurance coverage from a single carrier. Children who had 1 of 4 LTCs (substantial prematurity, critical congenital heart disease, cancer, or a condition resulting in severe neurologic impairment) were identified by a diagnosis in their insurance claim data between July 1, 2015, and June 30, 2016. Each case child and their family was matched with up to 4 control children and their families based on the age of the case and control children. Data were analyzed between August 2020 and March 2021. Exposures: Having a child or sibling with substantial prematurity, critical congenital heart disease, cancer, or a condition resulting in severe and progressive neurologic impairment. Main Outcomes: Rates of occurrence of health care encounters, physical and mental health diagnoses, and physical and mental health medication prescriptions, identified from insurance claims data, were compared between case and control families using a multivariable negative binomial regression model. The statistical analysis adjusted for observed differences between case and control families and accounted for clustering at the family level. Results: The study included 25 528 children (6909 case children [27.1%] and 18 619 control children [72.9%]; median age, 6.0 years [IQR, 1-13 years]; 13 294 [52.1%] male), 43 357 parents (11 586 case parents [26.7%] and 31 771 control parents [73.3%]; mean [SD] age, 40.4 [8.1] years; 22 318 [51.5%] female), and 25 706 siblings (7664 case siblings [29.8%] and 18 042 control siblings [70.2%]; mean [SD] age, 12.1 [6.5] years; 13 114 [51.0%] male). Overall, case mothers had higher rates of the composite outcome of health care encounters, diagnoses, and prescriptions compared with control mothers (incident rate ratio [IRR], 1.61; 95% CI, 1.54-1.68), as did case fathers compared with control fathers (IRR, 1.55; 95% CI, 1.46-1.64). Sisters of children with LTCs had higher rates of the composite outcome compared with sisters of children without LTCs (IRR, 1.68; 95% CI, 1.55-1.82), as did brothers of children with LTCs compared with brothers of children without LTCs (IRR, 1.70; 95% CI, 1.56-1.85). Conclusions and Relevance: In this cohort study, mothers, fathers, sisters, and brothers who had a child or sibling with 1 of 4 types of LTCs had higher rates of health care encounters, diagnoses, and medication prescriptions compared with families who did not have a child with that condition. The findings suggest that family members of children with LTCs may experience poorer mental and physical health outcomes. Interventions for parents and siblings of children with LTCs that aim to safeguard their mental and physical well-being appear to be warranted.

Effect of age and neurofibromatosis type 1 status on white matter integrity in the optic radiations.

BACKGROUND: Adults with neurofibromatosis type 1 (NF1) have decreased white matter integrity, but differences in children with NF1 have not been described. Defining normal values for diffusion tensor imaging (DTI) measures, especially in the optic radiations, is important to the development of DTI as a potential biomarker of visual acuity in children with optic pathway glioma. This study examines the effect of age and NF1 status on DTI measures in children. METHODS: In this retrospective study, MR imaging including DTI was conducted in 93 children (40 children with NF1 and 53 healthy controls) between 0 and 14 years of age. Regression models of age, sex, and NF1 status on DTI measures were evaluated, and tract-based spatial statistics (TBSS) compared DTI measures in age-matched NF1 to non-NF1 cohorts. RESULTS: Fractional anisotropy, radial diffusivity, and mean diffusivity in white matter tracts of the optic radiations varied with age and were best modeled by a logarithmic function. Age-related DTI measure change was different in NF1 versus non-NF1 subjects. Normal values and 95% confidence intervals for age 0.5-12 years were derived for both groups. Differences in DTI measures between NF1 and non-NF1 groups at a range of ages were shown diffusely throughout the cerebral white matter using TBSS. CONCLUSIONS: Children with NF1 demonstrate increased diffusion throughout the brain compared to children without NF1 suggesting a potentially altered developmental trajectory of optic radiation microstructure. Defining normal values for white matter integrity in children with NF1 may help target early intervention efforts in this vulnerable group.

miRNA contributions to pediatric-onset multiple sclerosis inferred from GWAS.

OBJECTIVE: Onset of multiple sclerosis (MS) occurs in childhood for approximately 5% of cases (pediatric MS, or ped-MS). Epigenetic influences are strongly implicated in MS pathogenesis in adults, including the contribution from microRNAs (miRNAs), small noncoding RNAs that affect gene expression by binding target gene mRNAs. Few studies have specifically examined miRNAs in ped-MS, but individuals developing MS at an early age may carry a relatively high burden of genetic risk factors, and miRNA dysregulation may therefore play a larger role in the development of ped-MS than in adult-onset MS. This study aimed to look for evidence of miRNA involvement in ped-MS pathogenesis. METHODS: GWAS results from 486 ped-MS cases and 1362 controls from the U.S. Pediatric MS Network and Kaiser Permanente Northern California membership were investigated for miRNA-specific signals. First, enrichment of miRNA-target gene network signals was evaluated using MIGWAS software. Second, SNPs in miRNA genes and in target gene binding sites (miR-SNPs) were tested for association with ped-MS, and pathway analysis was performed on associated target genes. RESULTS: MIGWAS analysis showed that miRNA-target gene signals were enriched in GWAS (P = 0.038) and identified 39 candidate biomarker miRNA-target gene pairs, including immune and neuronal signaling genes. The miR-SNP analysis implicated dysregulation of miRNA binding to target genes in five pathways, mainly involved in immune signaling. INTERPRETATION: Evidence from GWAS suggests that miRNAs play a role in ped-MS pathogenesis by affecting immune signaling and other pathways. Candidate biomarker miRNA-target gene pairs should be further studied for diagnostic, prognostic, and/or therapeutic utility.

The contribution of secondhand tobacco smoke exposure to pediatric multiple sclerosis risk.

BACKGROUND: Pediatric acquired demyelinating syndromes (ADSs) are monophasic (mono-ADS) in 70% of cases and represent the first attack of multiple sclerosis (MS) in 30%. Secondhand tobacco smoke (SHS) exposure has been implicated as a risk factor for adult-onset MS. Little is known about whether SHS presents an additive risk beyond genetic factors and other environmental exposures associated with pediatric MS. METHODS: This study examined SHS exposure in 216 children with mono-ADS and 81 children with MS. Interactions between SHS, HLA-DRB1*15 alleles, serum 25-hydroxyvitamin D concentrations, and serological evidence of remote Epstein-Barr virus (EBV) exposure were evaluated. RESULTS: SHS exposure was more common in children with MS (37% exposed) compared to mono-ADS (29.5% exposed). Compared to mono-ADS, SHS exposure was not an independent risk factor for MS. When both SHS exposure and HLA-DRB1*15 were present, the odds for MS increased (odds ratio (OR) = 3.7; 95% confidence interval (CI): 1.17-11.9) compared to mono-ADS. Interactions between SHS and vitamin D or EBV did not associate with MS. CONCLUSION: Exposure to SHS is a risk factor for central nervous system (CNS) demyelination. Results suggest that SHS exposure and HLA-DRB1*15 interact to increase risk for MS in children diagnosed with mono-ADS.

Consensus guidelines for newborn screening, diagnosis and treatment of infantile Krabbe disease.

BACKGROUND: Krabbe disease is a rare neurodegenerative genetic disorder caused by deficiency of galactocerebrosidase. Patients with the infantile form of Krabbe disease can be treated at a presymptomatic stage with human stem cell transplantation which improves survival and clinical outcomes. However, without a family history, most cases of infantile Krabbe disease present after onset of symptoms and are ineligible for transplantation. In 2006, New York began screening newborns for Krabbe disease to identify presymptomatic cases. To ensure that those identified with infantile disease received timely treatment, New York public health and medical systems took steps to accurately diagnose and rapidly refer infants for human stem cell transplantation within the first few weeks of life. After 11 years of active screening in New York and the introduction of Krabbe disease newborn screening in other states, new information has been gained which can inform the design of newborn screening programs to improve infantile Krabbe disease outcomes. FINDINGS: Recent information relevant to Krabbe disease screening, diagnosis, and treatment were assessed by a diverse group of public health, medical, and advocacy professionals. Outcomes after newborn screening may improve if treatment for infantile disease is initiated before 30 days of life. Newer laboratory screening and diagnostic tools can improve the speed and specificity of diagnosis and help facilitate this early referral. Given the rarity of Krabbe disease, most recommendations were based on case series or expert opinion. CONCLUSION: This report updates recommendations for Krabbe disease newborn screening to improve the timeliness of diagnosis and treatment of infantile Krabbe disease. In the United States, several states have begun or are considering Krabbe disease newborn screening. These recommendations can guide public health laboratories on methodologies for screening and inform clinicians about the need to promptly diagnose and treat infantile Krabbe disease. The timing of the initial referral after newborn screening, the speed of diagnostic confirmation of infantile disease, and the transplantation center's experience and ability to rapidly respond to a suspected patient with newly diagnosed infantile Krabbe disease are critical for optimal outcomes.

Applications of optical coherence tomography in pediatric clinical neuroscience.

For nearly two centuries, the ophthalmoscope has permitted examination of the retina and optic nerve-the only axons directly visualized by the physician. The retinal ganglion cells project their axons, which travel along the innermost retina to form the optic nerve, marking the beginning of the anterior visual pathway. Both the structure and function of the visual pathway are essential components of the neurologic examination as it can be involved in numerous acquired, congenital and genetic central nervous system conditions. The development of optical coherence tomography now permits the pediatric neuroscientist to visualize and quantify the optic nerve and retinal layers with unprecedented resolution. As optical coherence tomography becomes more accessible and integrated into research and clinical care, the pediatric neuroscientist may have the opportunity to utilize and/or interpret results from this device. This review describes the basic technical features of optical coherence tomography and highlights its potential clinical and research applications in pediatric clinical neuroscience including optic nerve swelling, optic neuritis, tumors of the visual pathway, vigabatrin toxicity, nystagmus, and neurodegenerative conditions.

Characteristic brain magnetic resonance imaging pattern in patients with macrocephaly and PTEN mutations.

We describe an MRI phenotype seen in a series of patients with mutations in PTEN who have clinical features consistent with PTEN hamartoma tumor syndrome (PHTS). Retrospective review of clinical data and MRI was performed in 23 subjects evaluated in four different tertiary care centers with clinical programs in inherited disorders of the white matter. Patients were referred due to abnormal MRI features and abnormal PTEN sequencing was identified. All subjects had significant macrocephaly (on average >4 SD above the mean), developmental delay with or without autism spectrum disorder and uniform MRI features of enlarged perivascular spaces and multifocal periventricular white matter abnormalities. The phenotype of PHTS may include MRI abnormalities such as multifocal periventricular white matter abnormalities and enlarged perivascular spaces. These neuroimaging findings, in association with macrocephaly and developmental delay, should prompt consideration of PTEN as a diagnostic possibility.