Longitudinal Study Of Infants Research Articles

Higher HIV-1 evolutionary rate is associated with cytotoxic T lymphocyte escape mutations in infants.

Escape from cytotoxic T lymphocyte (CTL) responses toward HIV-1 Gag and Nef has been associated with reduced control of HIV-1 replication in adults. However, less is known about CTL-driven immune selection in infants as longitudinal studies of infants are limited. Here, 1,210 gag and 1,264 nef sequences longitudinally collected within 15 months after birth from 14 HIV-1 perinatally infected infants and their mothers were analyzed. The number of transmitted founder (T/F) viruses and associations between virus evolution, selection, CTL escape, and disease progression were determined. The analyses indicated that a paraphyletic-monophyletic relationship between the mother-infant sequences was common (80%), and that the HIV-1 infection was established by a single T/F virus in 10 of the 12 analyzed infants (83%). Furthermore, most HIV-1 CTL escape mutations among infants were transmitted from the mothers and did not revert during the first year of infection. Still, immune-driven selection was observed at approximately 3 months after HIV-1 infection in infants. Moreover, virus populations with CTL escape mutations in gag evolved faster than those without, independently of disease progression rate. These findings expand the current knowledge of HIV-1 transmission, evolution, and CTL escape in infant HIV-1 infection and are relevant for the development of immune-directed interventions in infants.IMPORTANCEDespite increased coverage in antiretroviral therapy for the prevention of perinatal transmission, paediatric HIV-1 infection remains a significant public health concern, especially in areas of high HIV-1 prevalence. Understanding HIV-1 transmission and the subsequent virus adaptation from the mother to the infant's host environment, as well as the viral factors that affect disease outcome, is important for the development of early immune-directed interventions for infants. This study advances our understanding of vertical HIV-1 transmission, and how infant immune selection pressure is shaping the intra-host evolutionary dynamics of HIV-1.

The slow emergence of gaze- and point-following: A longitudinal study of infants from 4 to 12 months.

Acquisition of visual attention-following skills, notably gaze- and point-following, contributes to infants' ability to share attention with caregivers, which in turn contributes to social learning and communication. However, the development of gaze- and point-following in the first 18 months remains controversial, in part because of different testing protocols and standards. To address this, we longitudinally tested N=43 low-risk, North American middle-class infants' tendency to follow gaze direction, pointing gestures, and gaze-and-point combinations. Infants were tested monthly from 4 to 12 months of age. To control motivational differences, infants were taught to expect contingent reward videos in the target locations. No-cue trials were included to estimate spontaneous target fixation rates. A comparison sample (N=23) was tested at 9 and 12 months to estimate practice effects. Results showed gradual increases in both gaze- and point-following starting around 7 months, and modest month-to-month individual stability from 8 to 12 months. However, attention-following did not exceed chance levels until after 6 months. Infants rarely followed cues to locations behind them, even at 12 months. Infants followed combined gaze-and-point cues more than gaze alone, and followed points at intermediate levels (not reliably different from the other cues). The comparison group's results showed that practice effects did not explain the age-related increase in attention-following. The results corroborate and extend previous findings that North American middle-class infants' attention-following in controlled laboratory settings increases slowly and incrementally between 6 and 12 months of age. RESEARCH HIGHLIGHTS: A longitudinal experimental study documented the emergence and developmental trajectories of North American middle-class infants' visual attention-following skills, including gaze-following, point-following, and gaze-and-point-following. A new paradigm controlled for factors including motivation, attentiveness, and visual-search baserates. Motor development was ruled out as a predictor or limiter of the emergence of attention-following. Infants did not follow attention reliably until after 6 months, and following increased slowly from 7 to 12 months. Infants' individual trajectories showed modest month-to-month stability from 8 to 12 months of age.

Evolution of nutritional status and associated factors among formula-fed infants with cow’s milk protein allergy in a government program

BackgroundCow’s milk protein allergy (CMPA) is a common allergy in infants and can affect proper growth and development. This study verified factors associated with the evolution of the nutritional status (NS) among infants with CMPA fed with hypoallergenic formulas (HF).MethodsThis is a longitudinal study of infants (n = 1036) participating on a governmental program in Brazil. Researchers assessed Nutritional status before HF treatment (T1) and after HF treatment (T2). The causality of exposure variables on the evolution of NS was verified by Multinomial Logistic Regression (MLR).ResultsWe observed an increase in anthropometric indexes analyzed with statistically significant results (p < 0.01). The weight/age and height/age scores showed a significant reduction in infants with nutritional deficit. The Body Mass Index (BMI) showed a decrease in the number of infants with nutritional deficit (< -2 z-score). On the other hand, there was an increase in those classified as at risk of overweight, overweight and obese. MLR showed that those who remained < 12 months in the program had a lower odds ratio (95% CI = 0.355–0.906; p = 0.018) to have inadequate NS with increasing BMI. Preterm infants were 4 times more likely (CI 95% = 1.520–10.694; p = 0.005) to have their BMI decreased and those who received nutritional counseling had a lower odds ratio (CI 95% = 0.411–0.953; p = 0.029) to maintain adequate NS.ConclusionThe program has a significant impact on the NS of infants with CMPA. The constant management and implementation of differentiated criteria according to the evolution of NS for the supply of HF is fundamental in the continuity of this public policy.

Factors related to retention in a longitudinal study of infants at familial risk for autism.

Reporting retention data is critical to determining the soundness of a study's conclusions (internal validity) and broader generalizability (external validity). Although selective attrition can lead to overestimates of effects, biased conclusions, or overly expansive generalizations, retention rates are not reported in many longitudinal studies. We examined multiple child- and family-level factors potentially associated with retention in a longitudinal study of younger siblings of children with autism spectrum disorder (ASD; n=304) or typical development (n=163). The sample was followed from the first year of life to 36months of age, for up to 7 visits. Of the 467 infant siblings who were consented and participated in at least one research visit, 397 (85.0%) were retained to study completion at 36months. Retention rates did not differ by familial risk group (ASD-risk vs. Low-risk), sex, race, ethnicity, age at enrollment, number of children in the family, maternal employment, marital status, or parent concerns about the child at enrollment. A stepwise regression model identified 4 variables that, together, provided the most parsimonious predictive model of study retention: maternal education, maternal age at child's birth, travel distance to the study site, and diagnostic outcome classification at the final study visit. The retained and not-retained groups did not differ on most demographic and clinical variables, suggesting few threats to internal and external validity. The significantly higher rate of retention of children diagnosed with ASD (95%) than typically developing children (83%) may, however, present biases when studying recurrence risk. We conclude by describing engagement and tracking methods that can be used to maximize retention in longitudinal studies of children at risk of ASD.

839A novel approach to investigating poor growth in a longitudinal study of infants in PNG

Abstract Background Children in Papua New Guinea (PNG) experience high rates of malnutrition and poor growth - nearly half of children under 5 are stunted and 16% wasted. Methods We investigated predictors of infant growth over the first year of life using longitudinal data from mothers and infants in PNG. Between 2015 and 2018, 699 pregnant women were enrolled. At delivery, one, 6- and 12-months post-partum blood samples and anthropometric measurements were taken from mothers and infants. Using structural equation modelling with full information maximum likelihood, multivariate latent growth curve (LGC) modelling for infant weight and length (i.e. simultaneous estimation) was undertaken, and maternal factors that influenced growth investigated. Results A quadratic function for growth (weight and height) was estimated. Boys were larger at birth (49cm, 3.2kg vs. 48cm, 3.0kg; Wald χ2(2) =15.3, p&amp;lt;0.001) and gained more weight and length monthly (Wald χ2(4) =68.4, p&amp;lt;0.001). Maternal height, MUAC and number of antenatal healthcare visits were associated with birth weight and length, but not growth. Maternal nutrition and infections, breastfeeding and complementary feeding were not associated with birth size or growth. Conclusions Maternal height and MUAC and antenatal healthcare were associated with birth size and no maternal factors were associated with growth. Prenatal interventions to improve postnatal infant growth may be challenging in this environment Key messages Compared to conventional LGC analysis, multivariate LGC modelling using SEM provides less biased estimates of infant growth and factors associated with growth, particularly in the presence of missing data and infant-specific weight and height heterogeneity.

Infant Effortful Control Mediates Relations Between Nondirective Parenting and Internalising-Related Child Behaviours in an Autism-Enriched Infant Cohort

Internalising problems are common within Autism Spectrum Disorder (ASD); early intervention to support those with emerging signs may be warranted. One promising signal lies in how individual differences in temperament are shaped by parenting. Our longitudinal study of infants with and without an older sibling with ASD investigated how parenting associates with infant behavioural inhibition (8–14 months) and later effortful control (24 months) in relation to 3-year internalising symptoms. Mediation analyses suggest nondirective parenting (8 months) was related to fewer internalising problems through an increase in effortful control. Parenting did not moderate the stable predictive relation of behavioural inhibition on later internalising. We discuss the potential for parenting to strengthen protective factors against internalising in infants from an ASD-enriched cohort.

Comparison of Parent Questionnaires, Examiner-Led Assessment and Parents\u2019 Concerns at 14 Months of Age as Indicators of Later Diagnosis of Autism

Parents participating in a prospective longitudinal study of infants with older siblings with autism completed an autism screening questionnaire and were asked about any concerns relating to their child’s development, and children were administered an interactive assessment conducted by a researcher at 14 months. Scores on the parent questionnaire were highest for children later diagnosed with autism. Parental concerns and scores from the examiner-led assessment distinguished children with later developmental difficulties (both autism and other developmental atypicalities) from those who were developing typically. Children about whom parents expressed concern scored higher on both the questionnaire and the interactive assessment than those without concerns. There were no significant associations between total or individual item scores from the questionnaire and interactive assessment.

16.1 ASD AS A DISORDER OF EARLY POSTNATAL DEVELOPMENT: MAPPING SYMPTOM TRAJECTORIES

It has been known for more than 40 years that ASD runs in families, yet only for the last 15 years have prospective, longitudinal studies of infants at high familial risk for ASD, the so-called “baby sibling research paradigm,” demonstrated that defining features of this disorder arise postnatally in the first few years of life. Although the pathogenic roots of ASD have been linked to the midtrimester expression of specific genes and prenatal exposures (eg, valproic acid) are known to increase risk, baby sibling studies have now demonstrated convincingly that infants who meet the criteria for ASD by age 24 or 36 months do not exhibit core autistic social deficits at 6 months of age, although they display disturbances in other domains whose impairment is not specific to ASD. The objective of this presentation is to describe relevant behaviors and their trajectories during the presymptomatic period for ASD, given that the first few years of life may provide a critical window to study the unfolding of the biology underlying this disorder.

Joint visual attention and locomotor experience: A longitudinal study of infants with treated idiopathic clubfoot

AbstractThe aim of this study was to examine the link between joint attention skills and locomotor experiences in infants with locomotor delay due to congenital idiopathic clubfoot compared to typically developing infants. Using a following of point and gaze gesture task, we repeatedly tested joint attention skills of 11 infants with congenital idiopathic clubfoot and 14 typically developing infants at the ages of 6, 9, and 12 months. Additionally, we tested all typically developing infants and eight infants treated for idiopathic clubfoot at onset of crawling on hand and knees and after they had been crawling for about 5 to 6 weeks. Our results confirmed a delayed onset of locomotion in infants treated for idiopathic clubfoot; however, our results did not indicate lower joint attention performances in those infants in general. Moreover, we found a positive effect of crawling on the development of joint attention skills in typically developing infants; however, not in infants treated for idiopathic clubfoot. Our results complement previous work by indicating that locomotor experience, especially crawling is an important, however not necessary agent for developing joint attention skills.Highlights We repeatedly tested the link between crawling experience and joint attention skills in typically developing and infants with locomotor delay due to congenital idiopathic clubfoot. We did not find poorer joint attention performances in clubfoot infants, however crawling facilitated the development of joint attention skills in typically developing infants. Results indicated that locomotor experience, especially crawling is an important, however not necessary agent for developing joint attention skills.

A longitudinal study of infants' early speech production and later letter identification.

Letter identification is an early metric of reading ability that can be reliability tested before a child can decode words. We test the hypothesis that early speech production will be associated with children’s later letter identification. We examined longitudinal growth in early speech production in 9 typically developing children across eight occasions, every 3 months from 9 months to 30 months. At each occasion, participants and their caregivers engaged in a speech sample in a research lab. This speech sample was transcribed for a variety of vocalizations, which were then transformed to calculate consonant-vowel ratio. Consonant-vowel ratio is a measure of phonetic complexity in speech production. At the age of 72 months, children’s letter knowledge was measured. A multilevel model including fixed quadratic age change and a random intercept was estimated using letter identification as a predictor of the growth in early speech production from 9–30 months, measured by the outcome of consonant-vowel ratio. Results revealed that the relation between early speech production and letter identification differed over time. For each additional letter that a child identified, their consonant-vowel ratio at the age of 9 months increased. As such, these results confirmed our hypothesis: more robust early speech production is associated with more accurate letter identification.

Data Mapping From Food Diaries to Augment the Amount and Frequency of Foods Measured Using Short Food Questionnaires.

Collecting accurate and detailed dietary intake data is costly at a national level. Accordingly, limited dietary assessment tools such as Short Food Questionnaires (SFQs) are increasingly used in large surveys. This paper describes a novel method linking matched datasets to improve the quality of dietary data collected. Growing Up in Ireland (GUI) is a nationally representative longitudinal study of infants in the Republic of Ireland which used a SFQ (with no portion sizes) to assess the intake of “healthy” and “unhealthy” food and drink by 3 years old preschool children. The National Preschool Nutrition Survey (NPNS) provides the most accurate estimates available for dietary intake of young children in Ireland using a detailed 4 days weighed food diary. A mapping algorithm was applied using food name, cooking method, and food description to fill all GUI food groups with information from the NPNS food datafile which included the target variables, frequency, and amount. The augmented data were analyzed to examine all food groups described in NPNS and GUI and what proportion of foods were covered, non-covered, or partially-covered by GUI food groups, as a percentage of the total number of consumptions. The term non-covered indicated a specific food consumption that could not be mapped using a GUI food group. “High sugar” food items that were non-covered included ready-to-eat breakfast cereals, fruit juice, sugars, syrups, preserves and sweeteners, and ice-cream. The average proportion of consumption frequency and amount of foods not covered by GUI was 44 and 34%, respectively. Through mapping food codes in this manner, it was possible, using density plots, to visualize the relative performance of the brief dietary instrument (SFQ) compared to the more detailed food diary (FD). The SFQ did not capture a substantial portion of habitual foods consumed by 3-year olds in Ireland. Researchers interested in focussing on specific foods, could use this approach to assess the proportion of foods covered, non-covered, or partially-covered by reference to the mapped food database. These results can be used to improve SFQs for future studies and improve the capacity to identify diet-disease relationships.

Feeding-Related Gut Microbial Composition Associates With Peripheral T-Cell Activation and Mucosal Gene Expression in African Infants.

Exclusive breastfeeding reduces the rate of postnatal human immunodeficiency virus (HIV) transmission compared to nonexclusive breastfeeding; however, the mechanisms of this protection are unknown. Our study aimed to interrogate the mechanisms underlying the protective effect of exclusive breastfeeding. We performed a prospective, longitudinal study of infants from a high-HIV-prevalence, low-income setting in South Africa. We evaluated the role of any non-breast milk feeds, excluding prescribed medicines on stool microbial communities via 16S rRNA gene sequencing, peripheral T-cell activation via flow cytometry, and buccal mucosal gene expression via quantitative polymerase chain reaction assay. A total of 155 infants were recruited at birth with mean gestational age of 38.9 weeks and mean birth weight of 3.2 kg. All infants were exclusively breastfed (EBF) at birth, but only 43.5% and 20% remained EBF at 6 or 14 weeks of age, respectively. We observed lower stool microbial diversity and distinct microbial composition in exclusively breastfed infants. These microbial communities, and the relative abundance of key taxa, were correlated with peripheral CD4+ T-cell activation, which was lower in EBF infants. In the oral mucosa, gene expression of chemokine and chemokine receptors involved in recruitment of HIV target cells to tissues, as well as epithelial cytoskeletal proteins, was lower in EBF infants. These data suggest that nonexclusive breastfeeding alters the gut microbiota, increasing T-cell activation and, potentially, mucosal recruitment of HIV target cells. Study findings highlight a biologically plausible mechanistic explanation for the reduced postnatal HIV transmission observed in EBF infants.

The emergence of autism spectrum disorder: insights gained from studies of brain and behaviour in high-risk infants.

We review studies of infants at risk for autism spectrum disorder (ASD), proposing that the earliest manifestations of disrupted brain development can shed light on prebehavioural markers of risk and mechanisms underlying the heterogeneity of ASD. Prospective, longitudinal studies of infants at risk for ASD have revealed that behavioural signs of ASD are generally not observed until the second year of life. The developmental signs within the first year are often subtle and rooted in processes outside the core diagnostic domains of ASD, such as motor and visual perceptual function. However, studies examining early brain development and function have identified a myriad of atypicalities within the first year that are associated with risk for ASD. Longitudinal studies of high-risk infants provide a unique opportunity to identify and quantify the sources of the atypical development and developmental heterogeneity of ASD. Integration of assays of behaviour and brain in the first year of life, expansion of the definition of high risk, and coordinated efforts in multisite investigations to adequately power integrative studies will lead to new insights into mechanisms of atypical development and, ultimately, the ideal timing and target for interventions that aim to attenuate delays or impairments.

Celiac Disease Genomic, Environmental, Microbiome, and Metabolomic (CDGEMM) Study Design: Approach to the Future of Personalized Prevention of Celiac Disease.

In the past it was believed that genetic predisposition and exposure to gluten were necessary and sufficient to develop celiac disease (CD). Recent studies however suggest that loss of gluten tolerance can occur at any time in life as a consequence of other environmental stimuli. Many environmental factors known to influence the composition of the intestinal microbiota are also suggested to play a role in the development of CD. These include birthing delivery mode, infant feeding, and antibiotic use. To date no large-scale longitudinal studies have defined if and how gut microbiota composition and metabolomic profiles may influence the loss of gluten tolerance and subsequent onset of CD in genetically-susceptible individuals. Here we describe a prospective, multicenter, longitudinal study of infants at risk for CD which will employ a blend of basic and applied studies to yield fundamental insights into the role of the gut microbiome as an additional factor that may play a key role in early steps involved in the onset of autoimmune disease.

Optimizing early child development for young children with non-anemic iron deficiency in the primary care practice setting (OptEC): study protocol for a randomized controlled trial.

BackgroundThree decades of research suggests that prevention of iron deficiency anemia (IDA) in the primary care setting may be an unrealized and unique opportunity to prevent poor developmental outcomes in children. A longitudinal study of infants with IDA showed that the developmental disadvantage persists long term despite iron therapy. Early stages of iron deficiency, termed non-anemic iron deficiency (NAID), provide an opportunity for early detection and treatment before progression to IDA. There is little research regarding NAID, which may be associated with delayed development in young children. The aim of this study is to compare the effectiveness of four months of oral iron treatment plus dietary advice, with placebo plus dietary advice, in improving developmental outcomes in children with NAID and to conduct an internal pilot study.Methods/DesignFrom a screening cohort, those identified with NAID (hemoglobin ≥110 g/L and serum ferritin <14 μg/L) are invited to participate in a pragmatic, multi-site, placebo controlled, blinded, parallel group, superiority randomized trial. Participating physicians are part of a primary healthcare research network called TARGet Kids! Children between 12 and 40 months of age and identified with NAID are randomized to receive four months of oral iron treatment at 6 mg/kg/day plus dietary advice, or placebo plus dietary advice (75 per group). The primary outcome, child developmental score, is assessed using the Mullen Scales of Early Learning at baseline and at four months after randomization. Secondary outcomes include an age appropriate behavior measure (Children’s Behavior Questionnaire) and two laboratory measures (hemoglobin and serum ferritin levels). Change in developmental and laboratory measures from baseline to the end of the four-month follow-up period will be analyzed using linear regression (analysis of covariance method).DiscussionThis trial will provide evidence regarding the association between child development and NAID, and the effectiveness of oral iron to improve developmental outcomes in children with NAID. The sample size of the trial will be recalculated using estimates taken from an internal pilot study.Trial registrationThis trial was registered with Clinicaltrials.gov (identifier: NCT01481766) on 22 November 2011.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-015-0635-z) contains supplementary material, which is available to authorized users.

The Effects of Soothing Techniques and Rough-and-Tumble Play on the Early Development of Temperament: A Longitudinal Study of Infants

A total of 189 infants (93 girls, 96 boys) were investigated longitudinally at ages 4, 8, 12, 18, and 24 months to examine the effects of soothing techniques (i.e., distracting infants by presenting novel objects) and rough-and-tumble play on the early development of temperament, particularly the emergence of Effortful Control. We used questionnaires to examine the frequency of use of soothing techniques and rough-and-tumble play. The Infant Behavior Questionnaire Revised (IBQ-R) and the Early Childhood Behavior Questionnaire (ECBQ) were used to assess temperament. A strong relationship was found between parental ratings of their infant's Orienting/Regulation and later Effortful Control. Caregivers’ use of distracting as a soothing technique during infancy was associated with higher Negative Affect in toddlers at 24 months. More surgent infants were involved in more rough-and-tumble play, with rough-and-tumble play frequencies positively correlated with surgency scores at 24 months.

Long-Term Relationship Between Breastfeeding and Sleep

The aim of this study was to assess the relationship between breastfeeding and sleep in a longitudinal study of infants. Ninety-two mothers of exclusively breast-fed (n = 36) and exclusively formula-fed (n = 56) infants completed the Brief Infant Sleep Questionnaire at baseline (age of enrollment = 3 to 12 months) and at four follow-up visits (3, 6, 9, and 12 to 18 months). Breast-fed infants had more disrupted sleep at baseline including increased night wakings and sleep fragmentation; however, these differences disappeared by the 9-month follow-up. Furthermore, by the 6-month follow-up, parental presence at sleep onset played a more important role in sleep outcomes than breastfeeding. These findings suggest that sleep disruptions associated with breastfeeding resolve over time.

Risk of Bottle-feeding for Rapid Weight Gain During the First Year of Life

To better understand the mechanisms behind breastfeeding and childhood obesity, we assessed the association of weight gain with the mode of milk delivery aside from the type of milk given to infants. A longitudinal study of infants followed up from birth to age 1 year. Multilevel analyses were conducted to estimate infant weight gain by type of milk and feeding mode. Pregnant women were recruited from a consumer mail panel throughout the United States between May 2005 and June 2007. One thousand eight hundred ninety nine infants with at least 3 weight measurements reported during the first year. Six mutually exclusive feeding categories and proportions of milk feedings given as breastmilk or by bottle. Weight measurements reported on 3-, 5-, 7-, and 12-month surveys. Compared with infants fed at the breast, infants fed only by bottle gained 71 or 89 g more per month when fed nonhuman milk only (P < .001) or human milk only (P = .02), respectively. Weight gain was negatively associated with proportion of breastmilk feedings, but it was positively associated with proportion of bottle-feedings among those who received mostly breastmilk. Among infants fed only breastmilk, monthly weight gain increased from 729 g when few feedings were by bottle to 780 g when most feedings were by bottle. Infant weight gain might be associated not only with type of milk consumed but also with mode of milk delivery. Regardless of milk type in the bottle, bottle-feeding might be distinct from feeding at the breast in its effect on infants' weight gain.

School-age special education outcomes of infants and toddlers investigated for maltreatment

Examination of a nationally representative, longitudinal study of infants and toddlers investigated for maltreatment reveals disproportionate representation of teen mothers, fair/poor health, poverty, and being African-American. Infants are more likely to have special needs reported, subst`ance abusing caregivers, low-quality home environment, out-of-home placement, physical neglect, and substantiated maltreatment. At school-age, approximately one-fifth of all investigated infants and toddlers have an Individualized Education Program (IEP), indicating special education placement. Early characteristics associated with having an IEP include poverty, boys, fair/poor health, and low language scores. Hispanic children and those investigated for physical or sexual abuse were less likely to have an IEP. At school-age, infants had lower Woodcock–Johnson-III math subtests scores, whereas toddlers had lower reading comprehension performance.

Etiology of Severe Sensorineural Hearing Loss in Children: Independent Impact of Congenital Cytomegalovirus Infection andGJB2Mutations

Sensorineural hearing loss (SNHL) is the most common congenital disease. Longitudinal studies of infants with congenital cytomegalovirus (CMV) infection have demonstrated an association between CMV and SNHL. However, because of the lack of suitable neonatally collected specimens, the proportion of CMV-associated SNHL has not been defined, nor has the relationship between CMV and the major genetic causes of SNHL, such as mutations in the GJB2 gene. Sixty-seven children with severe SNHL were analyzed for CMV and human herpesvirus 6 (HHV-6) infections and for GJB2 mutations. DNA specimens were prepared from dried umbilical cords, which are available for everyone born in Japan. Four children with typical symptomatic infection at birth served as positive control subjects. Congenital CMV infection and GJB2 mutations were identified in 15% and 24% of the patients, respectively. HHV-6 was not detected. All children with CMV-associated cases developed SNHL before they were 2 years old. Most children with CMV-associated SNHL had no obvious clinical abnormality at birth, and their viral loads were lower than those of symptomatic children. Congenital CMV infection is an important cause of severe SNHL, and it has an incidence comparable to that of GJB2-associated SNHL.