Behavioral phenotype of Smith-Magenis syndrome (del 17p11.2)

Speech, Language, Hearing, and Otopathology Results From the International Smith-Magenis Syndrome Patient Registry

PURPOSE

Smith-Magenis syndrome (SMS), a rare, genetically linked complex developmental disorder caused by a deletion or mutation within chromosome 17p11.2, is associated with delays in speech-language development, otopathology, and hearing loss, yet previous studies lack comprehensive descriptions of hearing and communication profiles. Here, analyses of patient registry data expand what is known about speech, language, hearing, and otopathology in SMS.

METHOD

International speech-language and hearing registry survey data for 82 individuals with SMS were analyzed using descriptive and inferential statistics. Hearing loss, history of otitis media and pressure equalization (PE) tubes, communication mode, expressive/receptive language, and vocal quality were analyzed for all subjects and subjects grouped by age. Statistical methods included descriptive statistics and Pearson's chi-square tests of independence to test for differences between age groups for each variable of interest. Association analyses included Pearson's correlations.

RESULTS

Hearing and otological analyses revealed that 35% of subjects had hearing loss, 66% had a history of otitis media, and 62% had received PE tubes. Speech-language analyses revealed that 60% of subjects communicated using speech, 79% began speaking words at/after 24 months of age, 92% combined words at/after 36 months, and 41% used sign language before speech. There was a significant association between the age that first words were spoken and the age that PE tubes were first placed. Communication strengths noted in more than 40% of subjects included social interest, humor, and memory for people, past events, and/or facts.

CONCLUSIONS

Significant delays and impairment in speech-language were common, but the majority of those with SMS communicated using speech by age 6 years. Age was a significant factor for some aspects of hearing loss and communication. Neither hearing loss nor otitis media exacerbated language impairment. These results confirm and extend previous findings about the nature of speech, language, hearing, and otopathology in those with SMS.

Psychiatric and neurological manifestations in adults with Smith-Magenis syndrome: A scoping review

Smith-Magenis syndrome (SMS) is a neurodevelopmental disorder caused by a 17p11.2 deletion or a pathogenic variant of the RAI1 gene, which lies within the 17p11.2 region. Various psychiatric and neurological disorders have been reported in SMS, with most literature focusing on children and adolescents. To provide an overview of the current knowledge on this topic in adults with SMS, we performed a comprehensive scoping review of the relevant literature. Our findings suggest that many manifestations that are common in childhood persist into adulthood. Neuropsychiatric manifestations in adults with SMS include intellectual disability, autism spectrum- and attention deficit hyperactivity disorder-related features, self-injurious and physical aggressive behaviors, sleep-wake disorders, and seizures. Findings of this review may facilitate optimization of management strategies in adults with SMS, and may guide future studies exploring late-onset psychiatric and neurological comorbidities in SMS.

Melatonin in Neurodevelopmental Disorders: A Critical Literature Review

The article presents a review of the relationships between melatonin and neurodevelopmental disorders. First, the antioxidant properties of melatonin and its physiological effects are considered to understand better the role of melatonin in typical and atypical neurodevelopment. Then, several neurodevelopmental disorders occurring during infancy, such as autism spectrum disorder or neurogenetic disorders associated with autism (including Smith-Magenis syndrome, Angelman syndrome, Rett's syndrome, Tuberous sclerosis, or Williams-Beuren syndrome) and neurodevelopmental disorders occurring later in adulthood like bipolar disorder and schizophrenia, are discussed with regard to impaired melatonin production and circadian rhythms, in particular, sleep-wake rhythms. This article addresses the issue of overlapping symptoms that are commonly observed within these different mental conditions and debates the role of abnormal melatonin production and altered circadian rhythms in the pathophysiology and behavioral expression of these neurodevelopmental disorders.

Metabolic Profile of Patients with Smith-Magenis Syndrome: An Observational Study with Literature Review

Background: Smith-Magenis syndrome (SMS) is caused by either interstitial deletions in the 17p11.2 region or pathogenic variants in the RAI1 gene and is marked by a distinct set of physical, developmental, neurological, and behavioral features. Hypercholesterolemia has been described in SMS, and obesity is also commonly found. Aim: To describe and characterize the metabolic phenotype of a cohort of SMS patients with an age range of 2.9-32.4 years and to evaluate any correlations between their body mass index and serum lipids, glycated hemoglobin (HbA1c), and basal insulin levels. Results: Seven/thirty-five patients had high values of both total cholesterol and low-density lipoprotein cholesterol; 3/35 had high values of triglycerides; none of the patients with RAI1 variants presented dyslipidemia. No patients had abnormal fasting glucose levels. Three/thirty-five patients had HbA1c in the prediabetes range. Ten/twenty-two patients with 17p11.2 deletion and 2/3 with RAI1 variants had increased insulin basal levels. Three/twenty-three patients with the 17p11.2 deletion had prediabetes. Conclusion: Our investigation suggests that SMS 'deleted' patients may show a dyslipidemic pattern, while SMS 'mutated' patients are more likely to develop early-onset obesity along with hyperinsulinism.

A diagnosis of Birt-Hogg-Dubé syndrome in individuals with Smith-Magenis syndrome: Recommendation for cancer screening

We report a series of four unrelated adults with Smith-Magenis syndrome (SMS) and concomitant features of Birt-Hogg-Dubé (BHD) syndrome based upon haploinsufficiency for FLCN and characteristic renal cell carcinomas and/or evidence of cutaneous fibrofolliculomas. Three of the cases constitute the first known association of histopathologically verified characteristic BHD-associated renal tumors in adults with SMS; the fourth was identified to have histologically confirmed skin fibrofolliculomas. Molecular analysis documented second-hit FLCN mutations in two of the three cases with confirmed BHD renal pathology. These cases suggest the need to expand management recommendations for SMS to include kidney cancer surveillance starting at 20 years of age, as per the screening recommendations for BHD syndrome.

Smith-Magenis Syndrome—Clinical Review, Biological Background and Related Disorders

Smith-Magenis syndrome (SMS) is a complex genetic disorder characterized by distinctive physical features, developmental delay, cognitive impairment, and a typical behavioral phenotype. SMS is caused by interstitial 17p11.2 deletions (90%), encompassing multiple genes and including the retinoic acid-induced 1 gene (RAI1), or by pathogenic variants in RAI1 itself (10%). RAI1 is a dosage-sensitive gene expressed in many tissues and acting as transcriptional regulator. The majority of individuals exhibit a mild-to-moderate range of intellectual disability. The behavioral phenotype includes significant sleep disturbance, stereotypes, maladaptive and self-injurious behaviors. In this review, we summarize current clinical knowledge and therapeutic approaches. We further discuss the common biological background shared with other conditions commonly retained in differential diagnosis.

Effect of the use of an iPad on the attention span of a child with Smith Magenis Syndrome: A single case study

AIMS

To assess the effectiveness of iPad use on the attention span of a child with Smith Magenis Syndrome (n = 1), compared to attention span while working on the same tasks manually.

METHODS

An AB design with a baseline and an intervention phase was used. Three manual tasks were chosen for the baseline, which matched the participant's intellectual age by the Early Intervention Method: a jigsaw puzzle (six pieces), a shape sorter, and matching pictures. These same tasks were performed on an iPad during the intervention phase. Six baseline and nine intervention phase films were included in the analysis. The 15 films were independently scored twice by two observers: once to observe the types of distractions that occurred (such as standing up from the chair, calling the teacher, or turning around on the chair), and a second time to measure the effective working time.

RESULTS

iPad use led to a 45% decrease in the number of total distractions. The effective working time improved by 8% and showed a more consistent range compared to working on tasksbmanually. While task enjoyment was not directly measured, the observers and teachers agreed that working on the iPad appeared to be more enjoyable.

CONCLUSIONS

In this single case study the participant showed that in his case iPad use can be effective in decreasing his distractions and therefore can improve his attention span. Enjoyment was higher while working with the iPad than performing tasks manually. This technology could therefore create more learning engagement for the participant, which could positively impact his behavior. Further research into iPad implementation for children with intellectual disabilities, poor fine motor skills, and/or attention deficits is needed.

Twenty-four-hour motor activity and body temperature patterns suggest altered central circadian timekeeping in Smith-Magenis syndrome, a neurodevelopmental disorder

Smith-Magenis syndrome (SMS) is a contiguous gene syndrome linked to interstitial microdeletion, or mutation of RAI1, within chromosome 17p11.2. Key behavioral features of SMS include intellectual disability, sleep-disturbances, maladaptive, aggressive and self-injurious behaviors, hyperactivity, and sudden changes in mood. A distinguishing feature of this syndrome is an inverted pattern of melatonin characterized by elevated daytime and low nighttime melatonin levels. As the central circadian clock controls the 24-hr rhythm of melatonin, we hypothesized that the clock itself may contribute to the disrupted pattern of melatonin and sleep. In this report, 24-hr patterns of body temperature, a surrogate marker of clock-timing, and continuous wrist activity were collected to examine the links between body temperature, sleep behavior, and the circadian clock. In addition, age-dependent changes in sleep behavior were explored. Actigraphy-estimated sleep time for SMS was 1 hr less than expected across all ages studied. The timing of the 24-hr body temperature (Tb-24) rhythm was phase advanced, but not inverted. Compared to sibling (SIB) controls, the SMS group had less total night sleep, lower sleep efficiency, earlier sleep onset, earlier final awake times, increased waking after sleep onset (WASO), and increased daytime nap duration. The timing of wake onset varied with age, providing evidence of ongoing developmental sleep changes from childhood through adolescence. Clarification of the circadian and developmental factors that contribute to the disrupted and variable sleep patterns in this syndrome will be helpful in identifying more effective individualized treatments.

Sleep disorders in children with Angelman and Smith-Magenis syndromes: The assessment of potential causes of disrupted settling and night time waking

BACKGROUND

Sleep problems are common in Smith-Magenis (SMS) and Angelman syndromes (AS). Effectiveness of interventions depends on appropriate assessment, complicated by compromised self-report and health and behaviour difficulties. Studying settling and waking in these syndromes could inform assessment.

AIMS

To describe settling and waking behaviours in children at high-risk of sleep and health problems, using direct observation.

METHODS AND PROCEDURES

Video and actigraphy data were collected for 12 participants with AS (Mean age = 8.02, SD = 2.81) and 11 with SMS (Mean age = 8.80, SD = 2.18). Settling (30 min prior to sleep onset) and night waking were coded for nineteen behaviours relating to pain, challenging behaviour and caregiver interaction. Lag sequential analyses were conducted for pain-related behaviours.

OUTCOMES AND RESULTS

Percentage of time spent in behaviours was calculated. Parent-child interactions (0.00-9.93 %) and challenging behaviours (0 %) were rare at settling and waking in both groups. In the AS group, pain-related behaviours were more likely to occur before waking than by chance (p < 0.001).

CONCLUSIONS AND IMPLICATIONS

Findings highlight the importance of considering pain as a cause of sleep problems in AS. The principle and methodology could be extended to individuals with ID experiencing sleep problems.

Apical-Basal Polarity Signaling Components, Lgl1 and aPKCs, Control Glutamatergic Synapse Number and Function

Normal synapse formation is fundamental to brain function. We show here that an apical-basal polarity (A-BP) protein, Lgl1, is present in the postsynaptic density and negatively regulates glutamatergic synapse numbers by antagonizing the atypical protein kinase Cs (aPKCs). A planar cell polarity protein, Vangl2, which inhibits synapse formation, was decreased in synaptosome fractions of cultured cortical neurons from Lgl1 knockout embryos. Conditional knockout of Lgl1 in pyramidal neurons led to reduction of AMPA/NMDA ratio and impaired plasticity. Lgl1 is frequently deleted in Smith-Magenis syndrome (SMS). Lgl1 conditional knockout led to increased locomotion, impaired novel object recognition and social interaction. Lgl1+/- animals also showed increased synapse numbers, defects in open field and social interaction, as well as stereotyped repetitive behavior. Social interaction in Lgl1+/- could be rescued by NMDA antagonists. Our findings reveal a role of apical-basal polarity proteins in glutamatergic synapse development and function and also suggest a potential treatment for SMS patients with Lgl1 deletion.

The behavioural phenotype of Potocki-Lupski syndrome: a cross-syndrome comparison

Background

Potocki-Lupski syndrome (PTLS) and Smith-Magenis syndrome (SMS) are related genomic disorders, as duplication 17p11.2 (associated with PTLS) is the reciprocal recombination product of the SMS microdeletion. While SMS has a relatively well-delineated behavioural phenotype, the behavioural profile in PTLS is less well defined, despite purported associations with autism spectrum disorder (ASD) and the suggestion that some behaviours may be diametric to those seen in SMS.

Methods

Caregivers of individuals with PTLS (N = 34; M age = 12.43, SD = 6.78) completed online behavioural questionnaires, including the Challenging Behaviour Questionnaire (CBQ), the Activity Questionnaire (TAQ), the Repetitive Behaviour Questionnaire (RBQ), the Mood, Interest and Pleasure Questionnaire-Short Form (MIPQ-S) and the Social Communication Questionnaire (SCQ), which assesses behaviours associated with ASD. Individuals with PTLS were matched on age and adaptive functioning to individuals with SMS (N = 31; M age = 13.61, SD = 6.85) and individuals with idiopathic ASD (N = 33; M age = 12.04, SD = 5.85) from an existing dataset.

Results

Individuals with PTLS and SMS were less impaired than those with idiopathic ASD on the communication and reciprocal social interaction subscales of the SCQ, but neither syndrome group differed from idiopathic ASD on the restricted, repetitive and stereotyped behaviours subscale. On the repetitive behaviour measure, individuals with PTLS and idiopathic ASD scored higher than individuals with SMS on the compulsive behaviour subscale. Rates of self-injury and property destruction were significantly lower in PTLS and idiopathic ASD than in SMS. No between-syndrome differences were found in relation to overactivity or mood; however, impulsivity was greater in SMS than in PTLS.

Conclusions

Findings suggest some overlap in the behavioural phenotype of PTLS and features of ASD symptomatology; however, the overall profile of behaviours in PTLS appears to be divergent from both idiopathic ASD and SMS. Relative to idiopathic ASD, PTLS is not characterised by communication or social interaction deficits. However, restricted and repetitive behaviours were evident in PTLS, and these may be characterised specifically by compulsive behaviours. While several behavioural differences were identified between PTLS and SMS, there was little evidence of diametric behavioural phenotypes, particularly in relation to social behaviour.

Reversed gender ratio of autism spectrum disorder in Smith-Magenis syndrome

Background

A substantial amount of research shows a higher rate of autistic type of problems in males compared to females. The 4:1 male to female ratio is one of the most consistent findings in autism spectrum disorder (ASD).

Lately, the interest in studying ASD in genetic disorders has increased, and research has shown a higher prevalence of ASD in some genetic disorders than in the general population.

Smith-Magenis syndrome (SMS) is a rare and complex genetic syndrome caused by an interstitial deletion of chromosome 17p11.2 or a mutation on the retinoic acid induced 1 gene. The disorder is characterised by intellectual disability, multiple congenital anomalies, obesity, neurobehavioural abnormalities and a disrupted circadian sleep-wake pattern.

Methods

Parents of 28 persons with SMS between 5 and 50 years old participated in this study. A total of 12 of the persons with SMS were above the age of 18 at the time of the study. A total of 11 came from Sweden and 17 were from Norway.

We collected information regarding the number of autism spectrum symptoms using the Social Communication Questionnaire (SCQ) and the Social Responsiveness Scale (SRS). Adaptive behaviour was also measured using the Vineland Adaptive Behavior Scale II. The level of intellectual disability was derived from a review of the medical chart.

Results

We found significant gender differences in ASD symptomatology using the SCQ and SRS questionnaires. We found approximately three females per male above the SCQ cutoff. The same differences were not found in the intellectual level and adaptive behaviour or for behavioural and emotional problems.

Gender had an independent contribution in a regression model predicting the total SCQ score, and neither the Vineland Adaptive Behavior Scale II nor the Developmental Behaviour Checklist had an independent contribution to the SCQ scores.

Conclusion

We found a clear reversed gender difference in ASD symptomatology in persons with SMS. This may be relevant in the search for female protective factors assumed to explain the male bias in ASD.

RAI1 gene mutations: mechanisms of Smith-Magenis syndrome

Smith-Magenis syndrome (SMS; OMIM #182290) is a complex genetic disorder characterized by distinctive physical features, developmental delay, cognitive impairment, and a typical behavioral phenotype. SMS is caused by interstitial 17p11.2 deletions, encompassing multiple genes and including the retinoic acid-induced 1 gene (RAI1), or by mutations in RAI1 itself. About 10% of all the SMS patients, in fact, carry an RAI1 mutation responsible for the phenotype. RAI1 (OMIM *607642) is a dosage-sensitive gene expressed in many tissues and highly conserved among species. Over the years, several studies have demonstrated that RAI1 (or its homologs in animal models) acts as a transcriptional factor implicated in embryonic neurodevelopment, neuronal differentiation, cell growth and cell cycle regulation, bone and skeletal development, lipid and glucose metabolisms, behavioral functions, and circadian activity. Patients with RAI1 pathogenic variants show some phenotypic differences when compared to those carrying the typical deletion. They usually have lower incidence of hypotonia and less cognitive impairment than those with 17p11.2 deletions but more frequently show the behavioral characteristics of the syndrome and overeating issues. These differences reflect the primary pathogenetic role of RAI1 without the pathogenetic contribution of the other genes included in the typical 17p11.2 deletion. The better comprehension of physiological roles of RAI1, its molecular co-workers and interactors, and its contribution in determining the typical SMS phenotype will certainly open a new path for therapeutic interventions.

Rai1 frees mice from the repression of active wake behaviors by light

Besides its role in vision, light impacts physiology and behavior through circadian and direct (aka ‘masking’) mechanisms. In Smith-Magenis syndrome (SMS), the dysregulation of both sleep-wake behavior and melatonin production strongly suggests impaired non-visual light perception. We discovered that mice haploinsufficient for the SMS causal gene, Retinoic acid induced-1 (Rai1), were hypersensitive to light such that light eliminated alert and active-wake behaviors, while leaving time-spent-awake unaffected. Moreover, variables pertaining to circadian rhythm entrainment were activated more strongly by light. At the input level, the activation of rod/cone and suprachiasmatic nuclei (SCN) by light was paradoxically greatly reduced, while the downstream activation of the ventral-subparaventricular zone (vSPVZ) was increased. The vSPVZ integrates retinal and SCN input and, when activated, suppresses locomotor activity, consistent with the behavioral hypersensitivity to light we observed. Our results implicate Rai1 as a novel and central player in processing non-visual light information, from input to behavioral output.

DOI:http://dx.doi.org/10.7554/eLife.23292.001

Auditory Phenotype of Smith-Magenis Syndrome

Purpose

The purpose of this study was to describe the auditory phenotype of a large cohort with Smith-Magenis syndrome (SMS), a rare disorder including physical anomalies, cognitive deficits, sleep disturbances, and a distinct behavioral phenotype.

Method

Hearing-related data were collected for 133 individuals with SMS aged 1-49 years. Audiogram data (97 participants) were used for cross-sectional and longitudinal analyses. Caregivers completed a sound sensitivity survey for 98 individuals with SMS and a control group of 24 unaffected siblings.

Results

Nearly 80% of participants with interpretable audiograms (n = 76) had hearing loss, which was typically slight to mild in degree. When hearing loss type could be determined (40 participants), sensorineural hearing loss (48.1%) occurred most often in participants aged 11-49 years. Conductive hearing loss (35.2%) was typically observed in children aged 1-10 years. A pattern of fluctuating and progressive hearing decline was documented. Hyperacusis was reported in 73.5% of participants with SMS compared with 12.5% of unaffected siblings.

Conclusions

This study offers the most comprehensive characterization of the auditory phenotype of SMS to date. The auditory profile in SMS is multifaceted and can include a previously unreported manifestation of hyperacusis. Routine audiologic surveillance is recommended as part of standard clinical care.

Differences in Social Motivation in Children with Smith-Magenis Syndrome and Down Syndrome

Social excesses, characterised by heightened social motivation, are important for describing social functioning. Smith-Magenis syndrome (SMS) is a potential exemplar of a disorder where heightened social motivation is associated with negative behavioural outcomes. In Down syndrome (DS) strong social motivation is described, but less commonly associated with behavioural problems. Children with SMS (n = 21) and DS (n = 19) were observed during social situations, in which familiarity of adults present and level of attention available were manipulated. Motivation in SMS was characterised by comparatively frequent social initiations when adult attention was low, and stronger preference for familiar adults, compared to DS. Findings provide insight into the nature of social motivation in SMS and support an argument for nuanced consideration of motivation.

Individuals with Smith-Magenis syndrome display profound neurodevelopmental behavioral deficiencies and exhibit food-related behaviors equivalent to Prader-Willi syndrome

Smith-Magenis syndrome (SMS) is a neurodevelopmental disorder associated with intellectual disability, sleep disturbances, early onset obesity and vast behavioral deficits. We used the Behavior Problems Inventory-01 to categorize the frequency and severity of behavioral abnormalities in a SMS cohort relative to individuals with intellectual disability of heterogeneous etiology. Self-injurious, stereotyped, and aggressive/destructive behavioral scores indicated that both frequency and severity were significantly higher among individuals with SMS relative to those with intellectual disability. Next, we categorized food behaviors in our SMS cohort across age using the Food Related Problems Questionnaire (FRPQ) and found that problems began to occur in SMS children as early as 5-11 years old, but children 12-18 years old and adults manifested the most severe problems. Furthermore, we evaluated the similarities of SMS adult food-related behaviors to those with intellectual disability and found that SMS adults had more severe behavioral problems. Many neurodevelopmental disorders exhibit syndromic obesity including SMS. Prader-Willi syndrome (PWS) is the most frequent neurodevelopmental disorder with syndromic obesity and has a well-established management and treatment plan. Using the FRPQ we found that SMS adults had similar scores relative to PWS adults. Both syndromes manifest weight gain early in development, and the FRPQ scores highlight specific areas in which behavioral similarities exist, including preoccupation with food, impaired satiety, and negative behavioral responses. SMS food-related behavior treatment paradigms are not as refined as PWS, suggesting that current PWS treatments for prevention of obesity may be beneficial for individuals with SMS.

Behavioral disturbance and treatment strategies in Smith-Magenis syndrome

Background

Smith-Magenis syndrome is a complex neurodevelopmental disorder that includes intellectual deficiency, speech delay, behavioral disturbance and typical sleep disorders. Ninety percent of the cases are due to a 17p11.2 deletion encompassing the RAI1 gene; other cases are linked to mutations of the same gene. Behavioral disorders often include outbursts, attention deficit/hyperactivity disorders, self-injury with onychotillomania and polyembolokoilamania (insertion of objects into body orifices), etc. Interestingly, the stronger the speech delay and sleep disorders, the more severe the behavioral issues. Sleep disturbances associate excessive daytime sleepiness with nighttime agitation. They are underpinned by an inversion of the melatonin secretion cycle. However, the combined intake of beta-blockers in the morning and melatonin in the evening may radically alleviate the circadian rhythm problems.

Discussion

Once sleep disorders are treated, the next challenge is finding an effective treatment for the remaining behavioral problems. Unfortunately, there is a lack of objective guidelines. A comprehensive evaluation of such disorders should include sleep disorders, potential causes of pain, neurocognitive level and environment (i.e. family and school). In any case, efforts should focus on improving communication skills, identifying and treating attention deficit/hyperactivity, aggressiveness and anxiety.

Summary

Treatment of Smith-Magenis syndrome is complex and requires a multidisciplinary team including, among others, geneticists, psychiatrists, neuropediatricians/neurologists, somnologists, developmental and behavioral pediatricians, and speech and language therapists.

Congenital scoliosis in Smith-Magenis syndrome: a case report and review of the literature

The Smith-Magenis syndrome (SMS) is a complex and rare congenital condition that is characterized by minor craniofacial anomalies, short stature, sleep disturbances, behavioral, and neurocognitive abnormalities, as well as variable multisystemic manifestations. Little is reported about spinal deformity associated with this syndrome.This study is to present a case of scoliosis occurring in the setting of SMS and explore the possible mechanisms between the 2 diseases.The patient is a 13-year-old Chinese female with congenital scoliosis and Tetralogy of Fallot, mental retardation, obstructive sleep apnea, hypertrophy of tonsil, conductive hearing loss, and agenesis of the epiglottis. An interphase fluorescent in situ hybridization at chromosome 17p11.2 revealed a heterozygous deletion, confirming a molecular diagnosis of SMS. She underwent a posterior correction at thoracic 1-lumbar 1 (T1-L1) levels, using the Moss-SI spinal system. At 6-month follow-up, the patient was clinically pain free and well balanced. Plain radiographs showed solid spine fusion with no loss of correction.Congenital cardiac disease, immunodeficiency, and severe behavioral problems can affect the surgical outcome following spine fusion and need to be taken into consideration for the surgeon and anesthesiologist. Scoliosis is not uncommon among patients with SMS, and there is a potential association between congenital scoliosis and SMS. The potential mechanisms in the pathogenesis of congenital scoliosis of SMS included retinoic acid-induced 1 (RAI1) microdeletion and RAI1 gene point mutation.

[Smith-Magenis syndrome is an association of behavioral and sleep/wake circadian rhythm disorders]

Smith-Magenis syndrome (SMS) is a genetic disorder characterized by the association of facial dysmorphism, oral speech delay, as well as behavioral and sleep/wake circadian rhythm disorders. Most SMS cases (90%) are due to a 17p11.2 deletion encompassing the RAI1 gene; other cases stem from mutations of the RAI1 gene. Behavioral issues may include frequent outbursts, attention deficit/hyperactivity disorders, self-injuries with onychotillomania and polyembolokoilamania (insertion of objects into bodily orifices), etc. It is noteworthy that the longer the speech delay and the more severe the sleep disorders, the more severe the behavioral issues are. Typical sleep/wake circadian rhythm disorders associate excessive daytime sleepiness with nocturnal agitation. They are related to an inversion of the physiological melatonin secretion cycle. Yet, with an adapted therapeutic strategy, circadian rhythm disorders can radically improve. Usually an association of beta-blockers in the morning (stops daily melatonin secretion) and melatonin in the evening (mimics the evening deficient peak) is used. Once the sleep disorders are controlled, effective treatment of the remaining psychiatric features is needed. Unfortunately, as for many orphan diseases, objective guidelines have not been drawn up. However, efforts should be focused on improving communication skills. In the same vein, attention deficit/hyperactivity disorders, aggressiveness, and anxiety should be identified and specifically treated. This whole appropriate medical management is underpinned by the diagnosis of SMS. Diagnostic strategies include fluorescent in situ hybridization (FISH) or array comparative genomic hybridization (array CGH) when a microdeletion is sought and Sanger sequencing when a point mutation is suspected. Thus, the diagnosis of SMS can be made from a simple blood sample and should be questioned in subjects of any age presenting with an association of facial dysmorphism, speech delay with behavioral and sleep/wake circadian rhythm disorders, and other anomalies including short stature and mild dysmorphic features.

Concrete and relational vocabulary: comparison between Williams and Smith-Magenis syndromes

We compared the performance of two clinical groups, Williams syndrome (WS) and Smith-Magenis syndrome (SMS), in terms of concrete and relational vocabulary. We analyzed (a) whether the WS group had an advantage in concrete vocabulary when compared to the SMS group, as good concrete vocabulary knowledge is considered a hallmark of WS; (b) if spatial processing difficulties in WS would be reflected specifically in their knowledge of relational spatial vocabulary; (c) if a specific vocabulary profile could be outlined for SMS. Our results show similar performances on receptive concrete and relational vocabulary in both groups. However, and as anticipated, performance on relational space concepts was significantly lower in the WS group.

Abnormal brain magnetic resonance imaging in two patients with Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a clinically recognizable contiguous gene syndrome ascribed to an interstitial deletion in chromosome 17p11.2. Seventy percent of SMS patients have a common deletion interval spanning 3.5 megabases (Mb). Clinical features of SMS include characteristic mild dysmorphic features, ocular anomalies, short stature, brachydactyly, and hypotonia. SMS patients have a unique neurobehavioral phenotype that includes intellectual disability, self-injurious behavior and severe sleep disturbance. Little has been reported in the medical literature about anatomical brain anomalies in patients with SMS. Here we describe two patients with SMS caused by the common deletion in 17p11.2 diagnosed using chromosomal microarray (CMA). Both patients had a typical clinical presentation and abnormal brain magnetic resonance imaging (MRI) findings. One patient had subependymal periventricular gray matter heterotopia, and the second had a thin corpus callosum, a thin brain stem and hypoplasia of the cerebellar vermis. This report discusses the possible abnormal MRI images in SMS and reviews the literature on brain malformations in SMS. Finally, although structural brain malformations in SMS patients are not a common feature, we suggest baseline routine brain imaging in patients with SMS in particular, and in patients with chromosomal microdeletion/microduplication syndromes in general. Structural brain malformations in these patients may affect the decision-making process regarding their management.

The nature of social preference and interactions in Smith-Magenis syndrome

This natural observation study was designed to evaluate hypothesized elevated 'attention-seeking' and preference for adult attention in Smith-Magenis syndrome. Ten children with Smith-Magenis syndrome were observed across one school day, together with an age matched sample of 10 children with Down syndrome. Levels of attention given to, and vigilance for, adults and peers were recorded and compared. Sequences of behaviour were analyzed to evaluate the temporal relationships between giving and receiving attention during adult-child interactions. Compared to children with Down syndrome, children with Smith-Magenis syndrome gave preferential attention to adults and looked towards adults significantly more than they looked towards peers. Sequential analyses revealed that while children with Smith-Magenis syndrome did not initiate interactions with adults more than children with Down syndrome did, reciprocity between child and adult social behaviours in Smith-Magenis syndrome within interactions was compromised. This less synchronous sequence of child and adult interactions in Smith-Magenis syndrome may be the result of children with Smith-Magenis syndrome attempting to initiate interaction at times when it is unavailable. The marked preference for interacting with adults over peers in Smith-Magenis syndrome indicates atypicality of social interaction in this syndrome.

Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a mental retardation syndrome with distinctive behavioral characteristics, dysmorphic features, and congenital anomalies ascribed to an interstitial deletion of chromosome 17p11.2. Severe sleep disturbances and maladaptive daytime behavior have been linked to an abnormal circadian rhythm of melatonin with a diurnal instead of nocturnal secretion of this hormone. SMS provides a demonstration of a biological basis for sleep disorder in a genetic disease. Considering that clock genes mediate the generation of circadian rhythm, haploinsufficiency for a circadian system gene, mapping to chromosome 17p11.2, may cause the inversion of the melatonin circadian rhythm in SMS. The disorder of circadian timing in SMS may also affect entrainment pathway (retinohypothalamic tract), pacemaker functions (suprachiasmatic nuclei), or synthesis and release of melatonin by the pineal gland. Elucidating pathophysiological mechanisms of behavioral phenotypes in genetic disease can provide an original therapeutic approach in SMS: blockade of endogenous melatonin production during the day combined with exogenous melatonin administration in the evening.

Early behavioural manifestation of Smith-Magenis syndrome (del 17p11.2) in a 4-month-old boy

OBJECTIVE

There is little systematic data on early neurodevelopmental functioning of infants with Smith-Magenis syndrome, since early diagnosis is rare.

METHODS

A boy with cytogenetically confirmed Smith-Magenis syndrome was videotaped at 4 months and 1 week of age. His posture and spontaneous movements were analysed without knowing the diagnosis.

RESULTS

The motor repertoire appeared significantly reduced; fidgety general movements, which are typical of that age, were missing. Posture was abnormal and overall movements were jerky and monotonous. The findings indicate a severe motor impairment by no more than 4 months of age.

CONCLUSION

It was concluded that an absence of fidgety movements that goes along with subtle dysmorphic features indicates an increased risk of maldevelopment and justifies the need to refer for genetic evaluation with the potential of facilitating earlier diagnosis.

Opposing phenotypes in mice with Smith-Magenis deletion and Potocki-Lupski duplication syndromes suggest gene dosage effects on fluid consumption behavior

A quantitative long-term fluid consumption and fluid-licking assay was performed in two mouse models with either an ∼2 Mb genomic deletion, Df(11)17, or the reciprocal duplication copy number variation (CNV), Dp(11)17, analogous to the human genomic rearrangements causing either Smith-Magenis syndrome [SMS; OMIM #182290] or Potocki-Lupski syndrome [PTLS; OMIM #610883], respectively. Both mouse strains display distinct quantitative alterations in fluid consumption compared to their wild-type littermates; several of these changes are diametrically opposing between the two chromosome engineered mouse models. Mice with duplication versus deletion showed longer versus shorter intervals between visits to the waterspout, generated more versus less licks per visit and had higher versus lower variability in the number of licks per lick-burst as compared to their respective wild-type littermates. These findings suggest that copy number variation can affect long-term fluid consumption behavior in mice. Other behavioral differences were unique for either the duplication or deletion mutants; the deletion CNV resulted in increased variability of the licking rhythm, and the duplication CNV resulted in a significant slowing of the licking rhythm. Our findings document a readily quantitated complex behavioral response that can be directly and reciprocally influenced by a gene dosage effect.

Genetic counseling, activism and 'genotype-first' diagnosis of developmental disorders

This paper presents a sociological examination of the role of genetic counselors as advocates, not only for patients and their families, but also for genetic conditions themselves. In becoming activists for new disorders, genetic counselors are helping to create new categories that will shape expectations and treatment regimens for both existing patients and those who are yet to be diagnosed. By virtue of their expertise and their position at the intersection of several key professions and constituencies, genetic counselors are likely to play a central role in the way the genetic testing technologies, and especially 'genotype-first' diagnosis, impacts the way we understand and categorize developmental difference. I outline some of the promises and dangers that this kind of activism holds for people with developmental disabilities, and particularly the challenge presented by systemic ascertainment bias in the face of genotype-phenotype uncertainty. I argue that new testing techniques like microarray analysis that do not need to be targeted on the basis of clinical presentation throw these challenges into sharp relief, and that the genetic counseling community should consider how to marry advocacy for new genetic conditions with an emphasis on the indeterminate developmental potential of every child.

Cognitive functioning in children and adults with Smith-Magenis syndrome

Smith-Magenis Syndrome (SMS) is a genetic neurodevelopmental disorder caused by a microdeletion on chromosome 17p11.2. This syndrome is characterized by a distinctive profile of physical, medical and neuropsychological characteristics. The latter include general mental disability, with the majority of individuals falling within the mild to moderate range. This study reports a detailed cognitive assessment of children and adults with SMS with the use of the Wechsler intelligence scales at three distinct levels of analysis: full scale IQ, factorial indices, and subtests. Child and adult samples were each compared to samples of age and gender-matched typically developing individuals. To our knowledge, this is the first study to systematically analyse the cognitive profile of individuals with SMS in Southern Europe. The present study confirmed mental disability, particularly within the moderate category, as a consistent feature of children and adults with SMS. Furthermore, both child and adult samples evidenced significant impairments in all four indices when compared with their typically developing counterparts. A specific pattern of strengths and weaknesses was discernible for both samples, with Verbal Comprehension emerging as a relative strength, whereas Working Memory appeared as a relative weakness. Finally, with the exception of two subtests in the perceptual domain, we found no evidence for a general cognitive decline with age.

Analysis of the sensory profile in children with Smith-Magenis syndrome

This study systematically assessed sensory processing in 34 children, aged 3-14 years, with Smith-Magenis syndrome (SMS) using the Sensory Profile Caregiver Questionnaire. Scores for the SMS cohort were significantly different from scores of the national sample of children with and without disabilities in all Sensory Profile categories and quadrants (p < .001). No main effects of age or gender were found, but an interaction effect of age by gender was found in Modulation of Sensory Input Affecting Emotional Responses, in which older females presented with the lowest scores. A significant decline over time was found in the Seeking pattern, reflecting increased vulnerability (p < .05). Nonsignificant trends suggest more vulnerabilities for older versus younger children, especially older females. The neurobehavioral phenotype in children with SMS is expanded by this description of sensory processing. How children with SMS experience and respond to everyday sensations informs multidisciplinary team decisions.

Copy number and SNP arrays in clinical diagnostics

The ability of chromosome microarray analysis (CMA) to detect submicroscopic genetic abnormalities has revolutionized the clinical diagnostic approach to individuals with intellectual disability, neurobehavioral phenotypes, and congenital malformations. The recognition of the underlying copy number variant (CNV) in respective individuals may allow not only for better counseling and anticipatory guidance but also for more specific therapeutic interventions in some cases. The use of CMA technology in prenatal diagnosis is emerging and promises higher sensitivity for several highly penetrant, clinically severe microdeletion and microduplication syndromes. Genetic counseling complements the diagnostic testing with CMA, given the presence of CNVs of uncertain clinical significance, incomplete penetrance, and variable expressivity in some cases. While oligonucleotide arrays with high-density exonic coverage remain the gold standard for the detection of CNVs, single-nucleotide polymorphism (SNP) arrays allow for detection of consanguinity and most cases of uniparental disomy and provide a higher sensitivity to detect low-level mosaic aneuploidies.

Fragile X syndrome: lifespan developmental implications for those without as well as with intellectual disability

PURPOSE OF REVIEW

Advances in developmental neuropsychiatry and the mental health needs of people with intellectual disability are creating ever greater understanding of the critical associations between human genome variations and psychological functioning throughout lifespan and across the entire intellectual ability spectrum. This review highlights the recent developments and their clinical implications for people with fragile X syndrome.

RECENT FINDINGS

There is substantial evidence for individuals of all ages and intellectual abilities being prone to psychological profiles determined not only by having a fragile X gene full mutation, but also by having premutations and intermediate alleles. The importance of these genetic contributors to mental life, if anything, increases with age. Premutation carriers are prone to neurodegenerative mid-life fragile X tremor-ataxia syndrome. Women with premutations experience premature ovarian insufficiency. Imbalances in the (gamma amino butyrie acid)-glutamate mediated postsynaptic cascade central neuronal pathways are a current focus of psychopharmacological enquiry, giving the hope of syndrome-specific medical treatments.

SUMMARY

Findings from genetic, neurological, biochemical, psychological and pharmacological research are combining to revolutionize understanding of the pathogenesis of developmental and psychological disabilities affecting individuals with fragile X syndrome irrespective of age, intelligence level and gene mutation status. Results of syndrome-specific medication trials are awaited.

Psychiatric features in children with genetic syndromes: toward functional phenotypes

Neurodevelopmental disorders with identified genetic etiologies present a unique opportunity to study gene-brain-behavior connections in child psychiatry. Parsing complex human behavior into dissociable components is facilitated by examining a relatively homogenous genetic population. As children with developmental delay carry a greater burden of mental illness than the general population, familiarity with the most common genetic disorders will serve practitioners seeing a general child population. In this article, basic genetic testing and 11 of the most common genetic disorders are reviewed, including the evidence base for treatment. Based on their training in child development, family systems, and multimodal treatment, child psychiatrists are well positioned to integrate cognitive, behavioral, social, psychiatric, and physical phenotypes, with a focus on functional impairment.

Mouse models of genomic syndromes as tools for understanding the basis of complex traits: an example with the smith-magenis and the potocki-lupski syndromes

Each human's genome is distinguished by extra and missing DNA that can be “benign” or powerfully impact everything from development to disease. In the case of genomic disorders DNA rearrangements, such as deletions or duplications, correlate with a clinical specific phenotype. The clinical presentations of genomic disorders were thought to result from altered gene copy number of physically linked dosage sensitive genes. Genomic disorders are frequent diseases (~1 per 1,000 births). Smith-Magenis syndrome (SMS) and Potocki-Lupski syndrome (PTLS) are genomic disorders, associated with a deletion and a duplication, of 3.7 Mb respectively, within chromosome 17 band p11.2. This region includes 23 genes. Both syndromes have complex and distinctive phenotypes including multiple congenital and neurobehavioral abnormalities. Human chromosome 17p11.2 is syntenic to the 32-34 cM region of murine chromosome 11. The number and order of the genes are highly conserved. In this review, we will exemplify how genomic disorders can be modeled in mice and the advantages that such models can give in the study of genomic disorders in particular and gene copy number variation (CNV) in general. The contributions of the SMS and PTLS animal models in several aspects ranging from more specific ones, as the definition of the clinical aspects of the human clinical spectrum, the identification of dosage sensitive genes related to the human syndromes, to the more general contributions as the definition of genetic locus impacting obesity and behavior and the elucidation of general mechanisms related to the pathogenesis of gene CNV are discussed.

Autism spectrum features in Smith-Magenis syndrome

Smith-Magenis syndrome (SMS; OMIM 182290) is a neurodevelopmental disorder characterized by a well-defined pattern of anomalies. The majority of cases are due to a common deletion in chromosome 17p11.2 that includes the RAI1 gene. In children with SMS, autistic-like behaviors and symptoms start to emerge around 18 months of age. This study included 26 individuals (15 females and 11 males), with a confirmed deletion (del 17p11.2). Parents/caregivers were asked to complete the Social Responsiveness Scale (SRS) and the Social Communication Questionnaire (SCQ) both current and lifetime versions. The results suggest that 90% of the sample had SRS scores consistent with autism spectrum disorders. Moreover, females showed more impairment in total T-scores (P = 0.02), in the social cognition (P = 0.01) and autistic mannerisms (P = 0.002) subscales. The SCQ scores are consistent to show that a majority of individuals may meet criteria for autism spectrum disorders at some point in their lifetime. These results suggest that SMS needs to be considered in the differential diagnosis of autism spectrum disorders but also that therapeutic interventions for autism are likely to benefit individuals with SMS. The mechanisms by which the deletion of RAI1 and contiguous genes cause psychopathology remain unknown but they provide a solid starting point for further studies of gene-brain-behavior interactions in SMS and autism spectrum disorders.

Pharmacological treatment of disruptive behavior in Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a complex genetic syndrome caused by an interstitial deletion of chromosome 17p11.2. Children and adults with SMS appear to have unique neurobehavioral problems that include: sleep disturbance, self-injurious and maladaptive behaviors, stereotypies, and sensory integration disorders. We gathered retrospective psychotropic use information from parents or other caregivers of 62 individuals with SMS who were asked about use of psychotropic medication from a list of commonly used psychiatric medications. For those drugs identified, respondents were asked to rate the experience with the particular medication using a likert-type scale. Drugs were grouped into seven main categories: (1) stimulants; (2) antidepressants; (3) antipsychotics; (4) sleep aides; (5) mood stabilizers; (6) alpha 2 agonists; and (7) benzodiazepines. Relative frequencies, means and standard deviations pertaining to age and medication effect were derived for each medication category. Six of the seven medication categories examined showed no meaningful deviations from the "no change" score. The benzodiazepine group showed a mild detrimental effect. There were no gender differences in efficacy. Use of psychotropic medication started early in life (mean age 5 years), particularly with sleep aides. Although no medication category was identified as efficacious in SMS, all the categories reported herein may be considered as an option for brief symptomatic relief.

Prevalence, phenomenology, aetiology and predictors of challenging behaviour in Smith-Magenis syndrome

BACKGROUND

The prevalence, phenomenology aetiology and correlates of four forms of challenging behaviour in 32 children and adults with Smith-Magenis syndrome (SMS) were investigated.

METHODS

Cognitive assessments, questionnaires and semi-structured interviews were used to gather data on intellectual disability, verbal and physical aggression, destructive behaviour and self-injury and on characteristics known to be associated with aggression.

RESULTS

Aggression in SMS was more prevalent (87%), but not more severe than aggression in contrast groups. Aggressive behaviour was more frequently associated with environmental contingencies (e.g. attention, escape and access to tangibles) than self-injury and destructive behaviours. Severity of challenging behaviours was associated with high impulsivity.

CONCLUSION

Aggression is seen in the majority of people with SMS. Results suggest that behavioural disinhibition and operant social reinforcement are associated with the manifestation of aggression.

Functional and cellular characterization of human Retinoic Acid Induced 1 (RAI1) mutations associated with Smith-Magenis Syndrome

Background

Smith-Magenis Syndrome is a contiguous gene syndrome in which the dosage sensitive gene has been identified: the Retinoic Acid Induced 1 (RAI1). Little is known about the function of human RAI1.

Results

We generated the full-length cDNA of the wild type protein and five mutated forms: RAI1-HA 2687delC, RAI1-HA 3103delC, RAI1 R960X, RAI1-HA Q1562R, and RAI1-HA S1808N. Four of them have been previously associated with SMS clinical phenotype. Molecular weight, subcellular localization and transcription factor activity of the wild type and mutant forms were studied by western blot, immunofluorescence and luciferase assays respectively. The wild type protein and the two missense mutations presented a higher molecular weight than expected, localized to the nucleus and activated transcription of a reporter gene. The frameshift mutations generated a truncated polypeptide with transcription factor activity but abnormal subcellular localization, and the same was true for the 1-960aa N-terminal half of RAI1. Two different C-terminal halves of the RAI1 protein (1038aa-end and 1229aa-end) were able to localize into the nucleus but had no transactivation activity.

Conclusion

Our results indicate that transcription factor activity and subcellular localization signals reside in two separate domains of the protein and both are essential for the correct functionality of RAI1. The pathogenic outcome of some of the mutated forms can be explained by the dissociation of these two domains.

Psychiatric features in children with genetic syndromes: toward functional phenotypes

Neurodevelopmental disorders with identified genetic etiologies present a unique opportunity to study gene-brain-behavior connections in child psychiatry. Parsing complex human behavior into dissociable components is facilitated by examining a relatively homogenous genetic population. As children with developmental delay carry a greater burden of mental illness than the general population, familiarity with the most common genetic disorders will serve practitioners seeing a general child population. In this article basic genetic testing and 11 of the most common genetic disorders are reviewed, including the evidence base for treatment. Based on their training in child development, family systems, and multimodal treatment, child psychiatrists are well positioned to integrate cognitive, behavioral, social, psychiatric, and physical phenotypes, with a focus on functional impairment.

Hypoventilation in REM sleep in a case of 17p11.2 deletion (Smith-Magenis syndrome)

We describe a 2-year-old baby affected by Smith-Magenis syndrome (SMS), due to 17p11.2 deletion, who presented repeated episodes of hemoglobin desaturation during REM sleep. The boy, aged 14 months, presented a phenotype characterized by psychomotor delay, right posterior plagiocephaly, telecanthus, strabismus, upslanting palpebral fissures, broad hypoplastic nasal bridge, short philtrum, deep ring shaped skin creases around the limbs, proximal syndactyly, bilateral hypoacusia. Polysomnographic (PSG) recording showed episodes of REM-related hypoventilation (hemoglobin desaturations without apneas or hypopneas). Sleep disorders are present in almost all the cases of SMS, but very few reports describe the sleep-related respiratory patterns. The finding of REM hypoventilation in SMS does not allow an unequivocal interpretation. It could reflect a subclinical restrictive respiratory impairment or, alternatively, an impairment of central respiratory control during REM sleep. In SMS children, respiratory abnormalities during sleep, and in particular during REM sleep, may cause sleep disruption, reduction of time spent in REM sleep, and daytime sleepiness. We therefore suggest that some sleep abnormalities described in SMS could be consequent to Sleep Disordered Breathing, and in particular to REM hypoventilation. Sleep studies in SMS should include the recording of respiratory parameters.

Surgical treatment of scoliosis in Smith-Magenis syndrome: a case report

Introduction

Smith-Magenis syndrome is a rare genetic condition associated with scoliosis in approximately 30% of cases. There is limited information in the literature on the treatment of scoliosis and the surgical outcome in patients with this condition. Characteristic features of the syndrome, such as the presence of congenital heart and renal disease, inherent immunodeficiency, as well as severe behavioural disorders may complicate the surgical treatment of patients.

Case presentation

We present the case of an 11-year-old British Caucasian girl with Smith-Magenis syndrome who developed a severe, progressive thoracic and lumbar scoliosis measuring 85° and 80°, respectively. She had no cardiac or renal anomalies. Brace treatment was unsuccessful to prevent deterioration of the scoliosis. Both curves were rigid on supine maximum side-bending and traction radiographs. Our patient underwent a posterior spinal arthrodesis with pedicle screw/hook and rod instrumentation and autologous iliac crest graft, supplemented by allograft bone. She had an uneventful postoperative course other than the development of a small wound dehiscence which required resuturing with no signs of a wound infection. A good correction of both scoliotic curvatures to 45° and 40° and a balanced spine in both the coronal and sagittal planes was achieved. Follow-up to skeletal maturity (4 years post-surgery) showed no loss of deformity correction, no detected pseudarthrosis and a good clinical outcome.

Conclusion

Patients with Smith-Magenis syndrome can develop a severe scoliosis that may require surgical treatment. Congenital cardiac and renal disease, immunodeficiency and severe behavioural problems can affect the surgical outcome following spinal arthrodesis and need to be taken into consideration. Our case demonstrates that surgical correction of the deformity can be performed safely on this group of patients, with a good outcome and an uncomplicated postoperative course.

Neurodevelopment of children under 3 years of age with Smith-Magenis syndrome

Systematic data regarding early neurodevelopmental functioning in Smith-Magenis syndrome are limited. Eleven children with Smith-Magenis syndrome less than 3 years of age (mean, 19 months; range, 5-34 months) received prospective multidisciplinary assessments using standardized measures. The total sample scored in the moderately to severely delayed range in cognitive functioning, expressive language, and motor skills and exhibited generalized hypotonia, oral-motor abnormalities, and middle ear dysfunction. Socialization skills were average, and significantly higher than daily living, communication, and motor abilities, which were below average. Mean behavior ratings were in the nonautistic range. According to exploratory analyses, the toddler subgroup scored significantly lower than the infant subgroup in cognition, expressive language, and adaptive behavior, suggesting that the toddlers were more delayed than the infants relative to their respective peers. Infants aged approximately 1 year or younger exhibited cognitive, language, and motor skills that ranged from average to delayed, but with age-appropriate social skills and minimal maladaptive behaviors. At ages 2 to 3 years, the toddlers consistently exhibited cognitive, expressive language, adaptive behavior, and motor delays and mildly to moderately autistic behaviors. Combining age groups in studies may mask developmental and behavioral differences. Increased knowledge of these early neurodevelopmental characteristics should facilitate diagnosis and appropriate intervention.

Genetics of scoliosis

Scoliosis is one of the oldest known deformities of humankind; however, the cause still remains ill defined. Although there is a lack of uniform agreement on the inclusion criteria for the definition of scoliosis, most investigators agree that a coronal curve must measure at least 10 degrees for the patient to be considered to have scoliosis. A broad range of articles were reviewed and the relevant publications that contributed information regarding the genetics of scoliosis were selected for inclusion in this report. Based on family pedigree and genetic studies, the proposed pattern of inheritance for markers of scoliosis are expected to be autosomal dominant, X-linked, multigene, or multifactorial. This is further complicated by locus heterogeneity, allele heterogeneity, and carrier states found in normal individuals. Although none of these modes of inheritance has been definitively proven, it appears that a multifactorial mode of inheritance with variable penetrance is the most likely method.

Genomic sister-disorders of neurodevelopment: an evolutionary approach

Genomic sister-disorders are defined here as diseases mediated by duplications versus deletions of the same region. Such disorders can provide unique information concerning the genomic underpinnings of human neurodevelopment because effects of diametric variation in gene copy number on cognitive and behavioral phenotypes can be inferred. We describe evidence from the literature on deletions versus duplications for the regions underlying the best-known human neurogenetic sister-disorders, including Williams syndrome, Velocardiofacial syndrome, and Smith-Magenis syndrome, as well as the X-chromosomal conditions Klinefelter and Turner syndromes. These data suggest that diametric copy-number alterations can, like diametric alterations to imprinted genes, generate contrasting phenotypes associated with autistic-spectrum and psychotic-spectrum conditions. Genomically based perturbations to the development of the human social brain are thus apparently mediated to a notable degree by effects of variation in gene copy number. We also conducted the first analyses of positive selection for genes in the regions affected by these disorders. We found evidence consistent with adaptive evolution of protein-coding genes, or selective sweeps, for three of the four sets of sister-syndromes analyzed. These studies of selection facilitate identification of candidate genes for the phenotypes observed and lend a novel evolutionary dimension to the analysis of human cognitive architecture and neurogenetic disorders.

The behavioural phenotype of Smith-Magenis syndrome: evidence for a gene-environment interaction

BACKGROUND

Behaviour problems and a preference for adult contact are reported to be prominent in the phenotype of Smith-Magenis syndrome. In this study we examined the relationship between social interactions and self-injurious and aggressive/disruptive behaviour in Smith-Magenis syndrome to explore potential operant reinforcement of problem behaviours and thus a gene-environment interaction.

METHOD

Observational data on five children with Smith-Magenis syndrome (age range 3 to 13 years) were collected for between 9 and 12 h. The associations between purported phenotypic behaviours and two environmental events (adult attention and demands) were examined using descriptive analysis.

RESULTS

All participants engaged in self-injurious behaviour and aggressive/disruptive outbursts. Sequential analyses of aggressive/disruptive outbursts and self-injury revealed that these behaviours were evoked by low levels of adult attention and led to increased levels of attention following the behaviours in three and two participants respectively out of the four for whom this analysis was possible.

CONCLUSIONS

Problem behaviour in Smith-Magenis syndrome was evoked by decreased social contact in three out of four children. These data, considered alongside the preference for adult contact and the significantly increased prevalence of these behaviours in Smith-Magenis syndrome, illustrate a potential gene-environment interaction for problem behaviour in this syndrome.

The evolutionary social brain: From genes to psychiatric conditions

The commentaries on our target article, “Psychosis and Autism as Diametrical Disorders of the Social Brain,” reflect the multidisciplinary yet highly fragmented state of current studies of human social cognition. Progress in our understanding of the human social brain must come from studies that integrate across diverse analytic levels, using conceptual frameworks grounded in evolutionary biology.