Sensorineural hearing loss in children and adults with Williams syndrome

Peripheral Auditory Pathway and ABR Characterization in Adults with Williams Syndrome

Introduction  Williams syndrome (WS) is a genetic disorder caused by a microdeletion in chromosome 7, affecting ∼ 28 genes. Studies have demonstrated conductive losses seemingly related to the absence of the elastin gene and mild to profound sensorineural losses due to cochlear fragility. Objective  To characterize and compare the peripheral auditory system and auditory brainstem response (ABR) of adults with WS and neurotypical adults matched by age and gender. Methods  We conducted a cross-sectional observational study with 30 individuals of both sexes, aged 18 to 37 years - 15 of them with WS (study group) and 15 with neither the syndrome nor hearing complaints (control group), matched for sex and age. The subjects underwent pure-tone and speech audiometry, acoustic immittance, transient-evoked otoacoustic emissions (TEOAEs), and ABR. Results  Early-onset sensorineural hearing loss was found in 53.3% of the study sample, mostly mild, occurring above 3 kHz. The TEOAEs were absent in 53.3% of assessed subjects; for those in whom they were present, the signal-to-noise responses were significantly lower than in the control group. In the ABR, increased absolute latencies were observed in waves I and III. Conclusion  Individuals with WS have early and progressive cochlear impairments, mainly affecting the basal region of the cochlea. They may have low brainstem changes which seem to begin in adulthood.

Early Neurobehavioral Characterization of the CD Mouse Model of Williams-Beuren Syndrome

Williams-Beuren syndrome (WBS) is a neurodevelopmental disorder caused by a chromosomic microdeletion (7q11.23). WBS has been modeled by a mouse line having a complete deletion (CD) of the equivalent mouse locus. This model has been largely used to investigate the etiopathological mechanisms of WBS, although pharmacological therapies have not been identified yet. Surprisingly, CD mice were so far mainly tested in adulthood, despite the developmental nature of WBS and the critical relevance of early timing for potential treatments. Here we provide for the first time a phenotypic characterization of CD mice of both sexes during infancy and adolescence, i.e., between birth and 7 weeks of age. CD pups of both sexes showed reduced body growth, delayed sensory development, and altered patterns of ultrasonic vocalizations and exploratory behaviors. Adolescent CD mice showed reduced locomotion and acoustic startle response, and altered social interaction and communication, the latter being more pronounced in female mice. Juvenile CD mutants of both sexes also displayed reduced brain weight, cortical and hippocampal dendritic length, and spine density. Our findings highlight the critical relevance of early neurobehavioral alterations as biomarkers of WBS pathology, underlying the importance of adolescence for identifying novel therapeutic targets for this neurological disorder.

Audiological profile and cochlear functionality in Williams syndrome

PURPOSE

to evaluate cochlear functionality in Williams syndrome (WS) individuals.

METHODS

a study with 39 individuals, being 22 with WS aged between 7 and 17 years, 15 male and 7 female, and 17 individuals with typical development and normal hearing. All individuals were evaluated using pure tone audiometry, acoustic immittance measurements, and Transient Evoked Otoacoustic Emissions (TEOAE). The audiological profile in individuals with WS was analyzed, and TEOAE responses were compared between WS individuals without hearing loss and typical developmental individuals.

RESULTS

The hearing loss was observed in 50% of patients, being 78.95% sensorineural and 21.05% mixed. This hearing loss was predominantly mild to moderate, affecting mainly frequencies above 3 kHz. As for TEOAE, there was a higher incidence of absence and lower amplitude responses in individuals with WS.

CONCLUSION

WS individuals have hair cell dysfunction, mainly in the basal region of the cochlea. Thus, TEOAE analysis is an important clinical resource to be considered in the routine audiological evaluation.

Auditory Profile of Children With Some Rare Neurodevelopmental Disorders

Neurodevelopmental disorder is an umbrella term comprising many muscular, skeletal, metabolic, endocrinal, systemic, and immune-related diseases, which are caused due to the improper/inaccurate development of the central nervous system. Most of these disorders are highly prevalent, but some express rarely in human beings. Such disorders with least prevalence rates are known as rare neurodevelopmental disorders. The sensory system is affected in all individuals with these rare neurodevelopmental disorders, although to a varying extent. Sensory processing in terms of hearing loss is reported by many researchers in many rare neurodevelopmental disorders, but the pathophysiology of audiological findings are seldom investigated. In this chapter, the authors highlight the possible relationship between underlying cause and the resultant audiological symptoms in some of the rare neurodevelopmental disorders. Further, the research studies on the audiological profiling in such disorders are discussed.

Impact of ERT and follow-up of 17 patients from the same family with a mild form of MPS II

BACKGROUND

Mucopolysaccharidosis type II, also known as Hunter syndrome, is a rare X-linked recessive disorder caused by deficiency of the lysosomal enzyme Iduronate-2- Sulfatase (IDS), leading to progressive accumulation of Glycosaminoglycans (GAGs) in several organs. Over the years, Enzyme Replacement Therapy (ERT) has provided significant benefits for patients, retarding the natural progression of the disease.

RESULTS

The authors evaluated 17 patients from the same family with a mild form of MPS type II; the proband had developed acute decompensated heart failure refractory to clinical measurements at 23 years and needed a rather urgent heart transplant; however, he died from surgical complications shortly after the procedure. Nevertheless, subsequent to his tragic death, 16 affected male relatives were detected after biochemical tests identifying the low or absent activity of the IDS enzyme and confirmed by molecular analysis of the IDS gene. Following diagnosis, different options of treatment were chosen: 6 patients started ERT with Elaprase® (Idursulfase) soon after, while the other 10 remained without ERT. Eventually, 4 patients in the latter group began ERT with Hunterase® (Idursulfase Beta). None presented adverse effects to either form of the enzyme. Among the 6 individuals without any ERT, two died of natural causes, after reaching 70 years. Despite the variable phenotype within the same family (mainly heart dysfunctions and carpal tunnel syndrome), all 14 remaining patients were alive with an independent lifestyle.

CONCLUSION

Here, the authors report the variable progress of the disease with and without ERT in a large Brazilian family with a slowly progressive form of MPS II, harboring the same missense variant in the IDS gene.

Phonological development in school-aged Kuwaiti Arabic children with Down syndrome: A pilot study

BACKGROUND

Studies on atypical phonological development are very limited for Arabic, and to date no studies on Arabic have investigated the development of phonology in children with conditions such as Down Syndrome. Arabic, like other Semitic languages, is rich in consonants and consonantal variation. However, it differs greatly from region to region, and so reports on individual dialects or regional dialects are necessary. Kuwaiti Arabic, the focus of the present paper, is similar to other dialects in the Gulf region.

AIM

This is a preliminary study to examine the phonological development of school-aged Kuwaiti Arabic-speaking children with Down Syndrome in order to start to address the research gap noted above.

METHODS & PROCEDURES

Six Kuwaiti Arabic-speaking children were recruited for this pilot study from integrated public schools where children with disabilities and typically developing children are enrolled in the State of Kuwait: three male and three female students, age range of 5;10-12;3 years. All participants had the same single word speech test of 100 words. The first author, a native speaker of Kuwaiti Arabic, audio-recorded and phonetically transcribed the sample with the help of two speech-language pathologists from Kuwait. Reliability was confirmed by the first author and another expert rater. Both match and mismatch analyses were performed and compared to existing literature.

OUTCOMES & RESULTS

Overall consonant accuracy across participants was 50%, with a variety of matches across consonant categories. However, the participants also exhibited a wide range of mismatches across positions in words and phonological features (place, manner, and laryngeal features). Place substitutions were the most frequent. Some sounds exhibited double (place and manner) mismatches. The most common word structure mismatch was consonant cluster reduction (no matches for word-initial clusters). Mismatch patterns resembled both those of normally developing Kuwaiti children and those of English speakers with Down Syndrome in certain ways.

CONCLUSIONS & IMPLICATIONS

This pilot study provides preliminary information for clinicians regarding the speech or children with Down Syndrome (DS), not only in Kuwait but also in the Gulf region where there are similarities to Kuwaiti Arabic.

Auditory hypersensitivity in Williams syndrome

OBJECTIVES

The objective of this study was to investigate auditory hypersensitivity in WS and to evaluate hyperacusis through standardized protocols, checking if it can be associated with the absence of acoustic reflexes in people with WS.

METHOD

The study was performed in 17 individuals with WS, aged between seven and 17 years old (10 males and seven females), and 17 individuals with typical development age- and gender-matched to individuals with WS. Statistical tests were used to analyze the responses collected with the Loudness Discomfort Level (LDL) test as well as ipsilateral and contralateral reflex responses.

RESULTS

Auditory hypersensitivity was commonly found. Individuals with WS had phonophobia and were less tolerant to high sound intensity, presenting a reduced discomfort threshold compared to those with typical development. However, hyperacusis was found in 35.29% of individuals with WS and was mild in 50% of cases. There was an association between hyperacusis and acoustic reflex responses, and individuals with absence of the contralateral acoustic reflex were more likely to have hyperacusis.

CONCLUSIONS

Individuals with WS have a high prevalence of auditory hypersensitivity, with the presence of phonophobia; however, hyperacusis was not as prevalent and may be associated with the absence of contralateral acoustic reflexes.

Oxidative Stress in Down and Williams-Beuren Syndromes: An Overview

Oxidative stress is the result of an imbalance in the redox state in a cell or a tissue. When the production of free radicals, which are physiologically essential for signaling, exceeds the antioxidant capability, pathological outcomes including oxidative damage to macromolecules, aberrant signaling, and inflammation can occur. Down syndrome (DS) and Williams-Beuren syndrome (WBS) are well-known and common genetic conditions with multi-systemic involvement. Their etiology is linked to oxidative stress with important causative genes, such as SOD-1 and NCF-1, respectively, of the diseases being primarily involved in the regulation of the redox state. Early aging, dementia, autoimmunity, and chronic inflammation are some of the main characteristics of these conditions that can be associated with oxidative stress. In recent decades, there has been a growing interest in the possible role of oxidative stress and inflammation in the pathology of these conditions. However, at present, few studies have investigated these correlations. We provide an overview of the current literature concerning the role of oxidative stress and oxidative damage in genetic syndromes with a focus on Down syndrome and WBS. We hope to provide new insights to improve the management of complications related to these diseases.

Abnormal auditory event-related potentials in Williams syndrome

Individuals with Williams Syndrome (WS) have specific auditory characteristics, including hypoacusis and hyperacusis, and music appreciation skills. Little is known about the functionality of the central auditory nervous system (CANS) for sound processing in WS. Thus, the objective of the present study was to evaluate the functionality of the CANS in individuals with WS, based on auditory event-related potentials, as far as cognitive and behavioral aspects are concerned. The study was carried out with 17 individuals, seven females and ten males, between seven and 17 years old, with WS, and 17 individuals with typical development matched by sex and chronological age to individuals with WS. None of these individuals had middle ear impairment or hearing loss. The subjects were evaluated for intelligence quotient, loudness discomfort level, and auditory event-related potentials with Tone Burst stimuli, on the oddball paradigm; the parents also answered the MTA-SNAP-IV questionnaire. Hyperacusis was found in six WS individuals and two individuals with typical development. In the present study, WS individuals present longer latency and reduced amplitude for P1, N1, N2 and P3 components. These results, suggesting a delay and hypoactive responses of the CANS in this syndrome, that cannot be related to the cognitive or behavioral aspects of these individuals, but it indicates a cortical immaturity to process acoustic stimuli.

Symptoms of Autism Spectrum Disorder in Children With Down Syndrome and Williams Syndrome

Research suggests that people with a Williams syndrome (WS) or Down syndrome (DS) diagnosis display an increased prevalence of autism spectrum disorder (ASD) when compared to the general population. This study aimed to examine characteristics of ASD in a group of children with DS or WS. Results suggest that children with DS and WS exhibit higher levels of autism symptoms than the general population, particularly in the area of unusual behaviors, and that these elevations are not solely due to deficits in adaptive behavior. There are many possible explanations for these elevations, such as issues with measurement, etiological overlap, or similar behavioral phenotypes. More research is needed to further our understanding of the overlap of ASD symptoms in these populations.

Characterization of the development of the mouse cochlear epithelium at the single cell level

Mammalian hearing requires the development of the organ of Corti, a sensory epithelium comprising unique cell types. The limited number of each of these cell types, combined with their close proximity, has prevented characterization of individual cell types and/or their developmental progression. To examine cochlear development more closely, we transcriptionally profile approximately 30,000 isolated mouse cochlear cells collected at four developmental time points. Here we report on the analysis of those cells including the identification of both known and unknown cell types. Trajectory analysis for OHCs indicates four phases of gene expression while fate mapping of progenitor cells suggests that OHCs and their surrounding supporting cells arise from a distinct (lateral) progenitor pool. Tgfβr1 is identified as being expressed in lateral progenitor cells and a Tgfβr1 antagonist inhibits OHC development. These results provide insights regarding cochlear development and demonstrate the potential value and application of this data set.

How the development of the cochlear epithelium is regulated is unclear. Here, the authors use single cell RNAseq analysis to provide insight into the transcriptional changes arising during development of the murine cochlear inner and outer hair cells.

Características da avaliação auditiva na síndrome de Williams: revisão sistemática

RESUMO Objetivo Identificar por meio de uma revisão sistemática da literatura quais são as características da avaliação audiológica clínica de indivíduos com síndrome de Williams. Estratégia de pesquisa Inicialmente foi determinada a seguinte pergunta de pesquisa: “Quais são as características da avaliação auditiva clínica em indivíduos com síndrome de Williams?”. A partir desta, foi realizado um levantamento bibliográfico em 4 bases de dados, utilizando-se dos seguintes descritores: síndrome de Williams (Williams syndrome), perda auditiva (hearing loss) e audiologia (audiology). Critérios de seleção Foram selecionados artigos com nível de evidência 1 ou 2, publicados na íntegra nos idiomas português brasileiro ou inglês. Análise dos dados Foram analisados os resultados obtidos nos testes auditivos utilizados na rotina clínica, incluindo: imitanciometria, audiometria tonal, emissões otoacústicas e potencial evocado auditivo de tronco encefálico. Resultados 209 estudos foram encontrados, porém apenas 12 contemplaram os critérios de inclusão para o estudo. Foi possível observar prevalência de curva timpanométrica do tipo A, que pode ocorrer juntamente com ausência de reflexos acústicos, perda auditiva neurossensorial de grau leve a moderado acometendo principalmente as frequências altas, emissões otoacústicas ausentes ou de menor amplitude e potencial evocado auditivo de tronco encefálico sem alteração retrococlear. Conclusão O comprometimento coclear é comum em indivíduos com síndrome de Williams e as principais alterações na avaliação auditiva nesta população são a ausência das emissões otoacústicas e dos reflexos acústicos bem como a presença de perda auditiva neurossensorial de grau leve a moderado principalmente nas frequências altas na audiometria tonal.

Elastin-driven genetic diseases

Elastic fibers provide recoil to tissues that undergo repeated deformation, such as blood vessels, lungs and skin. Composed of elastin and its accessory proteins, the fibers are produced within a restricted developmental window and are stable for decades. Their eventual breakdown is associated with a loss of tissue resiliency and aging. Rare alteration of the elastin (ELN) gene produces disease by impacting protein dosage (supravalvar aortic stenosis, Williams Beuren syndrome and Williams Beuren region duplication syndrome) and protein function (autosomal dominant cutis laxa). This review highlights aspects of the elastin molecule and its assembly process that contribute to human disease and also discusses potential therapies aimed at treating diseases of elastin insufficiency.

Quality of life in adolescents and adults with CHARGE syndrome

Health-related Quality of Life and the Impact of Childhood Neurologic Disability Scale were collected for 53 patients with CHARGE syndrome aged 13-39 years with a mean academic level of 4th grade. The most prevalent new and ongoing issues included bone health issues, sleep apnea, retinal detachment, anxiety, and aggression. Sleep issues were significantly correlated with anxiety, self-abuse, conduct problems, and autistic-like behaviors. Problems with overall health, behavior, and balance most affected the number of social activities in the individual's life. Sensory impairment most affected relationships with friends. Two contrasting case studies are presented and demonstrate that the quality of life exists on a broad spectrum in CHARGE syndrome, just as its physical features range from mild to very severe. A multitude of factors, including those beyond the physical manifestations, such as anxiety and sleep problems, influence quality of life and are important areas for intervention. © 2016 Wiley Periodicals, Inc.

Array CGH - A Powerful Tool in Molecular Diagnostic of Pathogenic Microdeletions - Williams-Beuren Syndrome - A Case Report

ABSTRACT: Williams-Beuren syndrome (WBS) (OMIM 194050) is caused by interstitial deletions or duplications of the 7q11.23 chromosomal region and characterised through a complex phenotype. We described a case diagnosed clinically and genetically confirmed through aCGH. Genetic assessment identified three microdeletions with a total size of 1.35 Mb located at 7q11.23. The deleted regions encompasses more than 30 genes including several protein coding genes such as ELN, LIMK1, FZDS, WBSCR22, WBSCR27, WBSCR28, STX1A, CLDN3, CLDN4, LAT2, ABHD11 or EIF4H .

Aging and sleep in Williams syndrome: accelerated sleep deterioration and decelerated slow wave sleep decrement

Specific developmental and aging trajectories characterize sleep electroencephalogram (EEG) of typically developing (TD) subjects. Williams syndrome (WS) is marked by sleep alterations and accelerated aging of several anatomo-functional and cognitive measures. Here we test the hypothesis of a premature aging of sleep in WS. Age-related changes of home recorded sleep EEG of 42 subjects (21 WS, 21 age- and gender matched TD subjects, age: 6-29 years) were tested by Pearson correlations and homogeneity-of-slopes analysis. Typical developmental/aging effects of sleep EEGs were observed in TD subjects. Accelerated aging in WS was confirmed by overall sleep/wake measures. Specifically, premature aging was evident in accelerated age-dependent declines in WS subjects' sleep efficiency, as well as in steeper age-related rises in wakefulness and wake after sleep onset (WASO) of the WS group. In contrast, NREM sleep-related measures indicated atypical decelerations of the developmental trends of WS subjects, characterized by the slowing down of the age-related slow wave sleep (SWS) declines mirrored by the lack of age-dependent increase in Stage 2 (S2) sleep. Age-effects in sleep EEG power spectra were not different among the groups. Objectively measured sleep disruption of subjects with WS is age-dependent and increasing with age. Moreover, these data suggest atypical pre- and postpubertal neural development in WS, with sleep/wake balance and REM sleep time indicating accelerated aging while NREM sleep composition revealing signs of an as yet unidentified, perhaps compensatory developmental delay.

Analysis of subtle auditory dysfunctions in young normal-hearing subjects affected by Williams syndrome

OBJECTIVE

To assess if young subjects affected by Williams syndrome (WS) with normal middle ear functionality and normal hearing thresholds might have subtle auditory dysfunctions that could be detected by using clinically available measurements.

METHODS

Otoscopy, acoustic reflexes, tympanometry, pure-tone audiometry, and distortion product otoacoustic emissions (DPOAEs) were measured in a group of 13 WS subjects and in 13 age-matched, typically developing control subjects. Participants were required to have normal otoscopy, A-type tympanogram, normal acoustic reflex thresholds, and pure-tone thresholds≤15 dB HL at 0.5, 1, and 2 kHz bilaterally. To limit the possible influence of middle ear status on DPOAE recordings, we analyzed only data from ears with pure-tone thresholds≤15 dB HL across all octave frequencies in the range 0.25-8 kHz, middle ear pressure (MEP)>-50 daPa, static compliance (SC) in the range 0.3-1.2 cm3, and ear canal volume (ECV) in the range 0.2-2 ml, and we performed analysis of covariance to remove the possible effects of middle ear variables on DPOAEs.

RESULTS

No differences in mean hearing thresholds, SC, ECV, and gradient were observed between the two groups, whereas significantly lower MEP values were found in WS subjects as well as significantly decreased DPOAEs up to 3.2 kHz after adjusting for differences in middle ear status.

CONCLUSIONS

Results revealed that WS subjects with normal hearing thresholds (≤15 dB HL) and normal middle ear functionality (MEP>-50 daPa, SC in the range 0.3-1.2 cm3, ECV in the range 0.2-2 ml) might have subtle auditory dysfunctions that can be detected by using clinically available methods. Overall, this study points out the importance of using otoacoustic emissions as a complement to routine audiological examinations in individuals with WS to detect, before the onset of hearing loss, possible subtle auditory dysfunctions so that patients can be early identified, better monitored, and promptly treated.

The role of GTF2IRD1 in the auditory pathology of Williams-Beuren Syndrome

Williams-Beuren Syndrome (WBS) is a rare genetic condition caused by a hemizygous deletion involving up to 28 genes within chromosome 7q11.23. Among the spectrum of physical and neurological defects in WBS, it is common to find a distinctive response to sound stimuli that includes extreme adverse reactions to loud, or sudden sounds and a fascination with certain sounds that may manifest as strengths in musical ability. However, hearing tests indicate that sensorineural hearing loss (SNHL) is frequently found in WBS patients. The functional and genetic basis of this unusual auditory phenotype is currently unknown. Here, we investigated the potential involvement of GTF2IRD1, a transcription factor encoded by a gene located within the WBS deletion that has been implicated as a contributor to the WBS assorted neurocognitive profile and craniofacial abnormalities. Using Gtf2ird1 knockout mice, we have analysed the expression of the gene in the inner ear and examined hearing capacity by evaluating the auditory brainstem response (ABR) and the distortion product of otoacoustic emissions (DPOAE). Our results show that Gtf2ird1 is expressed in a number of cell types within the cochlea, and Gtf2ird1 null mice showed higher auditory thresholds (hypoacusis) in both ABR and DPOAE hearing assessments. These data indicate that the principal hearing deficit in the mice can be traced to impairments in the amplification process mediated by the outer hair cells and suggests that similar mechanisms may underpin the SNHL experienced by WBS patients.

Heterozygous deletion of the Williams-Beuren syndrome critical interval in mice recapitulates most features of the human disorder

Williams-Beuren syndrome is a developmental multisystemic disorder caused by a recurrent 1.55-1.83 Mb heterozygous deletion on human chromosome band 7q11.23. Through chromosomal engineering with the cre-loxP system, we have generated mice with an almost complete deletion (CD) of the conserved syntenic region on chromosome 5G2. Heterozygous CD mice were viable, fertile and had a normal lifespan, while homozygotes were early embryonic lethal. Transcript levels of most deleted genes were reduced 50% in several tissues, consistent with gene dosage. Heterozygous mutant mice showed postnatal growth delay with reduced body weight and craniofacial abnormalities such as small mandible. The cardiovascular phenotype was only manifested with borderline hypertension, mildly increased arterial wall thickness and cardiac hypertrophy. The neurobehavioral phenotype revealed impairments in motor coordination, increased startle response to acoustic stimuli and hypersociability. Mutant mice showed a general reduction in brain weight. Cellular and histological abnormalities were present in the amygdala, cortex and hippocampus, including increased proportion of immature neurons. In summary, these mice recapitulate most crucial phenotypes of the human disorder, provide novel insights into the pathophysiological mechanisms of the disease such as the neural substrates of the behavioral manifestations, and will be valuable to evaluate novel therapeutic approaches.

Psycholinguistic abilities of children with Williams syndrome

The objective of this study was to investigate the psycholinguistic abilities of children with Williams syndrome (WS) and typically developing children using the Illinois Test of Psycholinguistic Abilities (ITPA). Performance on the ITPA was analysed in a group with WS (N=20, mean age=8.5 years, SD=1.62) and two typically developing groups, matched in mental (MA, N=20, mean age=4.92 years, SD=1.14) and chronological age (CA, N=19, mean age=8.35 years, SD=3.07). Overall, within-group analyses showed that individuals with WS displayed higher scalar scores on the visual reception and visual association subtests. When groups were compared, we observed inferior performance of the WS group on all ITPA subtests when compared with typically developing groups. Moreover, an interaction between reception and group was found, only the WS group demonstrated superior performance on the visual reception subtest when compared to the auditory reception subtest. Evidence from this study offers relevant contributions to the development of educational intervention programs for children with WS.

Severity of hyperacusis predicts individual differences in speech perception in Williams Syndrome

BACKGROUND

Williams Syndrome (WS) is a neurodevelopmental disorder of genetic origin, characterised by relative proficiency in language in the face of serious impairment in several other domains. Individuals with WS display an unusual sensitivity to noise, known as hyperacusis.

METHODS

In this study, we examined the extent to which hyperacusis interferes with the perception of speech in children and adults with WS. Participants were required to discriminate words which differed in one consonant of a cluster when these contrasts were embedded in a background of noise.

RESULTS

Although the introduction of noise interfered with performance on a consonant cluster discrimination task equally in the WS and control groups, the severity of hyperacusis significantly predicted individual variability in speech perception within the WS group.

CONCLUSIONS

These results suggest that alterations in sensitivity to input mediate atypical pathways for language development in WS, where hyperacusis exerts an important influence together with other non-auditory factors.

A comparative study of hearing loss in two microdeletion syndromes: velocardiofacial (22q11.2 deletion) and Williams (7q11.23 deletion) syndromes

OBJECTIVE

To comprehensively assess auditory impairments in velocardiofacial syndrome (VCFS) and Williams syndrome (WS).

STUDY DESIGN

Audiologic measurements were conducted with 62 subjects with VCFS and 44 subjects with WS, as well as two control groups consisting of 22 subjects with idiopathic developmental disability and 23 typically developing controls. An association between severity of hearing loss in VCFS and the (158)Val/Met polymorphism of the catechol-O-methyltransferase gene (COMT) was explored.

RESULTS

Hearing was significantly more impaired in the VCFS and WS groups compared with the developmental disability and typically developing groups. Audiologic abnormalities identified in both the VCFS and WS groups included high-tone hearing loss (predominantly sensorineural or mixed type), loss of acoustic reflex, and middle ear pathologies. In both the VCFS and WS groups, hearing loss severity was positively correlated with age. In the VCFS group, hearing loss was more severe in the subgroup carrying the COMT Val allele compared with the subgroup carrying the COMT Met allele.

CONCLUSIONS

Hearing impairments, including sensorineural hearing loss and acoustic reflex dysfunction, are very common in both VCFS and WS. Hearing loss is less severe in subjects with the COMT Met allele, possibly due to the protective effect of dopamine on the hearing system.

Auditory function and hearing loss in children and adults with Williams syndrome: cochlear impairment in individuals with otherwise normal hearing

Hearing loss is common in school-age individuals with Williams syndrome (WS) and extensive in adults. Prior studies with relatively small sample sizes suggest that hearing loss in WS has an early onset and may be progressive, yet the auditory phenotype and the scope of the hearing loss have not been adequately characterized. We used standard audiometric tools: Otoscopy, tympanometry, air-conduction (bone conduction when available) behavioral testing, and distortion product otoacoustic emissions (DPOAEs) to measure hearing sensitivity and outer hair cell function. We tested 81 individuals with WS aged 5.33-59.50 years. Sixty-three percent of the school-age and 92% of the adult participants had mild to moderately-severe hearing loss. The hearing loss in at least 50% was sensorineural. DPOAE testing corroborated behavioral results. Strikingly, 12 of 14 participants with hearing within normal limits bilaterally had 4,000-Hz DPOAE input/output (DPOAE IO) functions indicative of outer hair cell damage and impaired cochlear compression. Our results indicate that hearing loss is very common in WS. Furthermore, individuals with WS who have "normal" hearing as defined by behavioral thresholds may actually have sub-clinical impairments or undetected cochlear pathology. Our findings suggest outer hair cell dysfunction in otherwise normal hearing individuals. The DPOAE IO in this same group revealed growth functions typically seen in groups with noise-induced damage. Given this pattern of findings, individuals with WS may be at increased risk of noise-induced hearing loss. Recommendations regarding audiological testing for individuals with WS and accommodations for these individuals in both academic and nonacademic settings are provided.

Leftward lateralization of auditory cortex underlies holistic sound perception in Williams syndrome

BACKGROUND

Individuals with the rare genetic disorder Williams-Beuren syndrome (WS) are known for their characteristic auditory phenotype including strong affinity to music and sounds. In this work we attempted to pinpoint a neural substrate for the characteristic musicality in WS individuals by studying the structure-function relationship of their auditory cortex. Since WS subjects had only minor musical training due to psychomotor constraints we hypothesized that any changes compared to the control group would reflect the contribution of genetic factors to auditory processing and musicality.

METHODOLOGY/PRINCIPAL FINDINGS

Using psychoacoustics, magnetoencephalography and magnetic resonance imaging, we show that WS individuals exhibit extreme and almost exclusive holistic sound perception, which stands in marked contrast to the even distribution of this trait in the general population. Functionally, this was reflected by increased amplitudes of left auditory evoked fields. On the structural level, volume of the left auditory cortex was 2.2-fold increased in WS subjects as compared to control subjects. Equivalent volumes of the auditory cortex have been previously reported for professional musicians.

CONCLUSIONS/SIGNIFICANCE

There has been an ongoing debate in the neuroscience community as to whether increased gray matter of the auditory cortex in musicians is attributable to the amount of training or innate disposition. In this study musical education of WS subjects was negligible and control subjects were carefully matched for this parameter. Therefore our results not only unravel the neural substrate for this particular auditory phenotype, but in addition propose WS as a unique genetic model for training-independent auditory system properties.

Sensory modulation impairments in children with Williams syndrome

The ability to organize information detected by our senses ("sensory modulation") allows us to act or respond effectively to situations encountered, facilitating learning, social behavior, and day-to-day functioning. We hypothesized that children with Williams syndrome (WS) would demonstrate symptoms of poor sensory modulation and that these sensory modulation abnormalities contribute to the phenotype. Participants were 78 children with WS aged 4.00-10.95 years. Based on parent ratings on the Short Sensory Profile [SSP; Dunn, 1999], most children were classified as having definite sensory modulation issues. Cluster analysis identified the presence of two clusters varying in level of sensory modulation impairment. Children in the high impairment group demonstrated poorer adaptive functioning, executive functioning, more problem behaviors, and more difficult temperaments than children in the low impairment group.

Atypical hemispheric asymmetry in the perception of negative human vocalizations in individuals with Williams syndrome

Williams syndrome is a neurological condition associated with high levels of auditory reactivity and emotional expression combined with impaired perception of prosody. Yet, little is currently known about the neural organization of affective auditory processing in individuals with this disorder. The current study examines auditory emotion processing in individuals with Williams syndrome. Hemispheric organization for positive and negative human non-linguistic sound processing was compared in participants with and without the disorder using a dichotic listening paradigm. While controls exhibited an expected right cerebral hemisphere advantage for processing negative sounds, those with Williams syndrome showed the opposite pattern. No differences between the groups emerged for the positive stimuli. The results suggest aberrant processing of negative auditory information in Williams syndrome.

Expecting the worst: observations of reactivity to sound in young children with Williams syndrome

The study examined behavioral reactions to sound, including startle eye blinks, in young children with Williams syndrome (WS) using video-based observational techniques. Participants were 21 children with WS and 20 children with other developmental disabilities of mixed etiology between the ages of 2.5 and 6. Groups were matched for chronological age and developmental level. All children participated in a semi-structured play interaction including exposure to mild intensity sounds as emitted from conventional toys. Overall, 90% of the children in the WS group were observed to exhibit overt behavioral reactivity to mild intensity sounds, compared to only 20% in the mixed etiology group. Examination of the temporal sequence indicated that children with WS generally exhibited these behaviors before exposure to sound stimuli, suggesting a relation to anticipatory anxiety. Children with WS also exhibited significantly greater acoustic startle eye blinks, often viewed as an indication of heightened emotional state. Taken together, the current findings confirm the presence of heightened reactivity to sound in WS, behaviors previously investigated using parent report alone. The observed behaviors and their potential relation to anxiety are also discussed.

Diagnosis and management of medical problems in adults with Williams–Beuren syndrome

Williams-Beuren syndrome (WBS) is a multi-system disorder that requires ongoing management by a primary care physician familiar with the natural history and common medical problems associated with the condition. Some abnormalities are unique to WBS, such as the elastin arteriopathy that often manifests as supravalvar aortic stenosis and hypertension. Still other features, such as diverticulosis, are seen in the general population but tend to present earlier in WBS. Life long monitoring of the cardiovascular and endocrine systems is essential to the clinical management of individuals with Williams-Beuren syndrome. Constipation should be aggressively managed, and symptoms of abdominal pain should prompt an evaluation for diverticulosis/diverticulitis. While the mean IQ of WBS is in the mild mental retardation range, difficulties with attention and anxiety are more likely to negatively impact independent functioning in the adult with WBS. There is no evidence for decline in cognitive ability over time, but adaptive functioning may be improved with treatment of anxiety by both behavior and medical modalities.

Anxiety and otovestibular disorders: linking behavioral phenotypes in men and mice

Human anxiety and vestibular disorders have long been known to co-occur. Paralleling human clinical and non-clinical data, mounting genetic, pharmacological and behavioral evidence confirms that animal anxiety interplays and co-exists with vestibular/balance deficits. However, relatively few animal models have addressed the nature of this relationship. This paper examines side-by-side human psychiatric and otovestibular phenotypes with animal experimentation data, and outlines future directions of translational research in this field. Discussed here are recently developed specific animal models targeting this interplay, other traditional animal tests sensitive to altered anxiety and vestibular domains, and the existing problems with translation of animal data into human phenotypes. The role of hearing deficits and their contribution to anxiety and vestibular phenotypes are also outlined. Overall, the overlap between anxiety and balance disorders emerges as an important phenomenon in both animal and clinical studies, and may contribute markedly to the complexity of behavioral and physiological phenotypes. Animal experimental models that focus on the interplay between anxiety and vestibular disorders are needed to improve our understanding of this important biomedical problem.

Genomic rearrangements and gene copy-number alterations as a cause of nervous system disorders

Genomic disorders are a group of human genetic diseases caused by genomic rearrangements resulting in copy-number variation (CNV) affecting a dosage-sensitive gene or genes critical for normal development or maintenance. These disorders represent a wide range of clinically distinct entities but include many diseases affecting nervous system function. Herein, we review selected neurodevelopmental, neurodegenerative, and psychiatric disorders either known or suggested to be caused by genomic rearrangement and CNV. Further, we emphasize the cause-and-effect relationship between gene CNV and complex disease traits. We also discuss the prevalence and heritability of CNV, the correlation between CNV and higher-order genome architecture, and the heritability of personality, behavioral, and psychiatric traits. We speculate that CNV could underlie a significant proportion of normal human variation including differences in cognitive, behavioral, and psychological features.

Prevalence of psychiatric disorders in 4 to 16-year-olds with Williams syndrome

The prevalence of a range of DSM-IV psychiatric disorders in a sample of 119 4-16-year-old children with Williams syndrome (WS) was assessed using a structured diagnostic interview with their parents. Most children (80.7%) met criteria for at least one DSM-IV diagnosis. The most prevalent diagnoses were Attention Deficit/Hyperactivity Disorder (ADHD; 64.7%) and Specific Phobia (53.8%). There was a significant shift in Predominant Type of ADHD as a function of CA, from Combined for the youngest group (ages 4-6 years) to Inattentive for the oldest group (ages 11-16 years). The prevalence of Generalized Anxiety Disorder (GAD) increased significantly with age. These findings are another step toward defining the behavioral phenotype of WS.

Neural mechanisms in Williams syndrome: a unique window to genetic influences on cognition and behaviour

Williams syndrome, a rare disorder caused by hemizygous microdeletion of about 28 genes on chromosome 7q11.23, has long intrigued neuroscientists with its unique combination of striking behavioural abnormalities, such as hypersociability, and characteristic neurocognitive profile. Williams syndrome, therefore, raises fundamental questions about the neural mechanisms of social behaviour, the modularity of mind and brain development, and provides a privileged setting to understand genetic influences on complex brain functions in a 'bottom-up' way. We review recent advances in uncovering the functional and structural neural substrates of Williams syndrome that provide an emerging understanding of how these are related to dissociable genetic contributions characterized both in special participant populations and animal models.