Smith-Magenis syndrome

Prenatal Diagnosis of 17p11.2 Copy Number Abnormalities Associated With Smith-Magenis and Potocki-Lupski Syndromes in Fetuses

Smith-Magenis syndrome and Potocki-Lupski syndrome are rare autosomal dominant diseases. Although clinical phenotypes of adults and children have been reported, fetal ultrasonic phenotypes are rarely reported. A retrospective analysis of 6,200 pregnant women who received invasive prenatal diagnosis at Fujian Provincial Maternal and Child Health Hospital between October 2016 and January 2021 was performed. Amniotic fluid or umbilical cord blood was extracted for karyotyping and single nucleotide polymorphism array analysis. Single nucleotide polymorphism array analysis revealed six fetuses with copy number variant changes in the 17p11.2 region. Among them, one had a copy number variant microdeletion in the 17p11.2 region, which was pathogenically analyzed and diagnosed as Smith-Magenis syndrome. Five fetuses had copy number variant microduplications in the 17p11.2 region, which were pathogenically analyzed and diagnosed as Potocki-Lupski syndrome. The prenatal ultrasound phenotypes of the six fetuses were varied. The parents of two fetuses with Potocki-Lupski syndrome refused verification. Smith-Magenis syndrome in one fetus and Potocki-Lupski in another were confirmed as de novo. Potocki-Lupski syndrome in two fetuses was confirmed to be from maternal inheritance. The prenatal ultrasound phenotypes of Smith-Magenis syndrome and Potocki-Lupski syndrome in fetuses vary; single nucleotide polymorphism array analysis is a powerful diagnostic tool for these diseases. The ultrasonic phenotypes of these cases may enrich the clinical database.

Endogenous melatonin and sleep in individuals with Rare Genetic Neurodevelopmental Disorders (RGND): A systematic review

Individuals with Rare Genetic Neurodevelopmental Disorders (RGND) present with significant sleep problems and circadian rhythm abnormalities of uncertain aetiology. Abnormal melatonin secretion may play a role in sleep disturbance in individuals with higher incidence developmental disabilities, however, RGND research is limited. This review compared the melatonin profiles in a range of RGND with that of the general population and considered the impact of any differences on sleep. A systematic search identified 19 studies that met inclusion criteria. Each study was examined to extract data relating to the study design, participant characteristics, objectives, sleep measures and results, and melatonin measures and findings. Studies were evaluated using the BIOCROSS quality appraisal tool. Nine studies focussed on Smith-Magenis syndrome (SMS), the rest included individuals with Angelman (AS), Fragile-X (FXS), Prader-Willi (PWS), septo-optic dysplasia, PAX6/WAGR and Williams (WS) syndromes (N = 349). Individuals with RGND present with a range of sleep problems, particularly dyssomnias. The melatonin profile varied within and between RGND, with low nocturnal melatonin levels commonly reported. Understanding the relationship between specific sleep and melatonin parameters within RGND may help inform sleep intervention.

Circadian disruption, melatonin rhythm perturbations and their contributions to chaotic physiology

The aim of this report is to summarize the data documenting the vital nature of well-regulated cellular and organismal circadian rhythms, which are also reflected in a stable melatonin cycle, in supporting optimal health. Cellular fluctuations in physiology exist in most cells of multicellular organisms with their stability relying on the prevailing light:dark cycle, since it regulates, via specialized intrinsically-photoreceptive retinal ganglion cells (ipRGC) and the retinohypothalamic tract, the master circadian oscillator, i.e., the suprachiasmatic nuclei (SCN). The output message of the SCN, as determined by the light:dark cycle, is transferred to peripheral oscillators, so-called slave cellular oscillators, directly via the autonomic nervous system with its limited distribution. and indirectly via the pineal-derived circulating melatonin rhythm, which contacts every cell. Via its regulatory effects on the neuroendocrine system, particularly the hypothalamo-pituitary-adrenal axis, the SCN also has a major influence on the adrenal glucocorticoid rhythm which impacts neurological diseases and psychological behaviors. Moreover, the SCN regulates the circadian production and secretion of melatonin. When the central circadian oscillator is disturbed, such as by light at night, it passes misinformation to all organs in the body. When this occurs the physiology of cells becomes altered and normal cellular functions are compromised. This physiological upheaval is a precursor to pathologies. The deterioration of the SCN/pineal network is often a normal consequence of aging and its related diseases, but in today's societies where manufactured light is becoming progressively more common worldwide, the associated pathologies may also be occurring at an earlier age.

Sleep in children with Smith–Magenis syndrome: a case–control actigraphy study

Study Objectives

The objectives of the study were (1) to compare both actigraphy and questionnaire-assessed sleep quality and timing in children with Smith–Magenis syndrome (SMS) to a chronologically age-matched typically developing (TD) group and (2) to explore associations between age, nocturnal and diurnal sleep quality, and daytime behavior.

Methods

Seven nights of actigraphy data were collected from 20 children with SMS (mean age 8.70; SD 2.70) and 20 TD children. Daily parent/teacher ratings of behavior and sleepiness were obtained. Mixed linear modeling was used to explore associations between total sleep time and daytime naps and behavior.

Results

Sleep in children with SMS was characterized by shorter total sleep time (TST), extended night waking, shorter sleep onset, more daytime naps, and earlier morning waking compared to the TD group. Considerable inter-daily and inter-individual variability in sleep quality was found in the SMS group, so caution in generalizing results is required. An expected inverse association between age and TST was found in the TD group, but no significant association was found for the SMS group. No between-group differences in sleep hygiene practices were identified. A bidirectional negative association between TST and nap duration was found for the SMS group. In the SMS group, increased afternoon sleepiness was associated with increased irritability (p = .007) and overactivity (p = .005).

Conclusion

These findings evidence poor sleep quality in SMS and the need to implement evidence-based interventions in this population.

The use and misuse of exogenous melatonin in the treatment of sleep disorders

PURPOSE OF REVIEW

To explore the evidence for using exogenous melatonin in the treatment of sleep disorders, both primary and secondary, in children and adults.

RECENT FINDINGS

A number of recently published meta-analyses have shown that there is evidence for the efficacy of exogenously administered melatonin in a number of sleep disorders. However, melatonin is likely to be prescribed largely for reasons of perceived minimal side-effect profile and very low cost in situations in which high-quality evidence for its usefulness is not forthcoming.

SUMMARY

There is evidence for the efficacy of melatonin in the management of insomnia and some intrinsic disorders of circadian rhythm in adults and children as well as in reducing sleep onset latency in jet-lag and shift work disorder in adults. Melatonin is used routinely in the treatment of rapid-eye movement sleep-behaviour disorder despite limited trial evidence. Increasingly, dual melatonin receptor agonists are being trialled in a variety of sleep disorders. Long-term adverse effects are currently not fully identified.

Signatures of selection and environmental adaptation across the goat genome post-domestication

BACKGROUND

Since goat was domesticated 10,000 years ago, many factors have contributed to the differentiation of goat breeds and these are classified mainly into two types: (i) adaptation to different breeding systems and/or purposes and (ii) adaptation to different environments. As a result, approximately 600 goat breeds have developed worldwide; they differ considerably from one another in terms of phenotypic characteristics and are adapted to a wide range of climatic conditions. In this work, we analyzed the AdaptMap goat dataset, which is composed of data from more than 3000 animals collected worldwide and genotyped with the CaprineSNP50 BeadChip. These animals were partitioned into groups based on geographical area, production uses, available records on solid coat color and environmental variables including the sampling geographical coordinates, to investigate the role of natural and/or artificial selection in shaping the genome of goat breeds.

RESULTS

Several signatures of selection on different chromosomal regions were detected across the different breeds, sub-geographical clusters, phenotypic and climatic groups. These regions contain genes that are involved in important biological processes, such as milk-, meat- or fiber-related production, coat color, glucose pathway, oxidative stress response, size, and circadian clock differences. Our results confirm previous findings in other species on adaptation to extreme environments and human purposes and provide new genes that could explain some of the differences between goat breeds according to their geographical distribution and adaptation to different environments.

CONCLUSIONS

These analyses of signatures of selection provide a comprehensive first picture of the global domestication process and adaptation of goat breeds and highlight possible genes that may have contributed to the differentiation of this species worldwide.

Dissipative structures and biological rhythms

Sustained oscillations abound in biological systems. They occur at all levels of biological organization over a wide range of periods, from a fraction of a second to years, and with a variety of underlying mechanisms. They control major physiological functions, and their dysfunction is associated with a variety of physiological disorders. The goal of this review is (i) to give an overview of the main rhythms observed at the cellular and supracellular levels, (ii) to briefly describe how the study of biological rhythms unfolded in the course of time, in parallel with studies on chemical oscillations, (iii) to present the major roles of biological rhythms in the control of physiological functions, and (iv) the pathologies associated with the alteration, disappearance, or spurious occurrence of biological rhythms. Two tables present the main examples of cellular and supracellular rhythms ordered according to their period, and their role in physiology and pathophysiology. Among the rhythms discussed are neural and cardiac rhythms, metabolic oscillations such as those occurring in glycolysis in yeast, intracellular Ca⁺⁺ oscillations, cyclic AMP oscillations in Dictyostelium amoebae, the segmentation clock that controls somitogenesis, pulsatile hormone secretion, circadian rhythms which occur in all eukaryotes and some bacteria with a period close to 24 h, the oscillatory dynamics of the enzymatic network driving the cell cycle, and oscillations in transcription factors such as NF-ΚB and tumor suppressors such as p53. Ilya Prigogine's concept of dissipative structures applies to temporal oscillations and allows us to unify within a common framework the various rhythms observed at different levels of biological organization, regardless of their period and underlying mechanism.

Blood transcriptome based biomarkers for human circadian phase

Diagnosis and treatment of circadian rhythm sleep-wake disorders both require assessment of circadian phase of the brain’s circadian pacemaker. The gold-standard univariate method is based on collection of a 24-hr time series of plasma melatonin, a suprachiasmatic nucleus-driven pineal hormone. We developed and validated a multivariate whole-blood mRNA-based predictor of melatonin phase which requires few samples. Transcriptome data were collected under normal, sleep-deprivation and abnormal sleep-timing conditions to assess robustness of the predictor. Partial least square regression (PLSR), applied to the transcriptome, identified a set of 100 biomarkers primarily related to glucocorticoid signaling and immune function. Validation showed that PLSR-based predictors outperform published blood-derived circadian phase predictors. When given one sample as input, the R² of predicted vs observed phase was 0.74, whereas for two samples taken 12 hr apart, R² was 0.90. This blood transcriptome-based model enables assessment of circadian phase from a few samples.

DOI:http://dx.doi.org/10.7554/eLife.20214.001

Sleep Complaints and the 24-h Melatonin Level in Individuals with Smith-Magenis Syndrome: Assessment for Effective Intervention

AIMS

Individuals with Smith-Magenis syndrome (SMS) are reported to have a disrupted circadian rhythm. Our aim was to examine problematic sleeping in those attending our sleep clinic for the first time.

METHODS

At intake, caregivers of 50 children and nine adults with SMS were surveyed about the sleep pattern and potential melatonin administration. Sampling of salivary melatonin levels was performed.

RESULTS

At intake, exogenous melatonin was used by 16 children (27.1% of sample; 56.3% male) with mean age 6.8 ± 2.8 years, whereas 34 children (57.6%; 7.5 ± 4.8 years old; 64.7% male) and nine adults (15.3%; 36.8 ± 15.3 years old; 44.4% male) were not taking melatonin at intake. Participants were reported to have problems with night waking and early awakenings regardless of melatonin administration. Overall, moderate to high levels of salivary melatonin at noon were found in individuals with SMS. In particular, children with SMS showed a disrupted melatonin pattern. Furthermore, the endogenous melatonin level, age, and gender may potentially interact, yielding the severity range of sleep disturbances reported in SMS.

CONCLUSION

Treatment of sleep problems in SMS is complex, and our findings may support person-centered sleep and medication management. Future clinical trials including larger groups may shed light on such approaches.

Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders

Melatonin is a physiological hormone involved in sleep timing and is currently used exogenously in the treatment of primary and secondary sleep disorders with empirical evidence of efficacy, but very little evidence from randomised, controlled studies. The aim of this meta-analysis was to assess the evidence base for the therapeutic effects of exogenous melatonin in treating primary sleep disorders. An electronic literature review search of MEDLINE (1950-present) Embase (1980- present), PsycINFO (1987- present), and Scopus (1990- present), along with a hand-searching of key journals was performed in July 2013 and then again in May 2015. This identified all studies that compared the effect of exogenous melatonin and placebo in patients with primary insomnia, delayed sleep phase syndrome, non 24-h sleep wake syndrome in people who are blind, and rapid eye movement-behaviour disorder. Meta-analyses were performed to determine the magnitude of effect in studies of melatonin in improving sleep. A total of 5030 studies were identified; of these citations, 12 were included for review based on the inclusion criteria of being: double or single-blind, randomised and controlled. Results from the meta-analyses showed the most convincing evidence for exogenous melatonin use was in reducing sleep onset latency in primary insomnia (p = 0.002), delayed sleep phase syndrome (p < 0.0001), and regulating the sleep-wake patterns in blind patients compared with placebo. These findings highlight the potential importance of melatonin in treating certain first degree sleep disorders. The development of large-scale, randomised, controlled trials is recommended to provide further evidence for therapeutic use of melatonin in a variety of sleep difficulties.

Delayed diagnosis in a house of correction: Smith-Magenis syndrome due to a de novo nonsense RAI1 variant

We report a 25-year-old female confirmed to have Smith-Magenis syndrome (SMS) due to a de novo RAI1 variant. Her past history is significant for developmental and intellectual delay, early and escalating maladaptive behaviors, and features consistent with significant sleep disturbance, the etiology of which was not confirmed for over two decades. The diagnosis of SMS was initially suspected in 1998 (at age 12 years), but that was 5 years before the initial report of RAI1 variants as causative of the SMS phenotype; cytogenetic fluorescence in situ hybridization studies failed to confirm an interstitial deletion of 17p11.2. Re-evaluation for suspected SMS was pursued with RAI1 sequencing analysis in response to urgent parental concerns of escalating behaviors and aggression with subsequent incarceration of the subject for assault of a health professional. Genetic analysis revealed a de novo RAI1 (NM_030665.3) nonsense variant, c.5536C>T; p.Q1846X. This case illustrates the importance of confirming the SMS diagnosis, which is associated with cognitive and functional impairment, as well as significant psychiatric co-morbidities and behavioral problems. The diagnosis was particularly relevant to the legal discussion and determination of her competence to stand trial. As other similar cases may exist, this report will help to increase awareness of the possibility of a very late diagnosis of SMS, with the need for re-evaluation of individuals suspected to have SMS who were initially evaluated prior to the identification of the RAI1 gene. © 2016 Wiley Periodicals, Inc.

Williams-Beuren syndrome: computed tomography imaging review

Williams-Beuren syndrome (WBS) affects young infants and children. The underlying etiopathogenesis of this rare disease is due to the mutation of the elastin gene that is responsible for the elasticity of the arterial wall. As a result of inadequate elastin production, the major systemic arteries become abnormally rigid and can be manifested by an impediment to the blood flow. The most common cardiovascular abnormalities encountered in WBS are supravalvular aortic stenosis, pulmonary arterial stenosis, and mitral valve prolapse. Less frequently observed cardiovascular abnormalities include coarctation of the aorta, ventricular septal defect, patent ductus, subaortic stenosis, and hypertrophic cardiomyopathy. Coronary artery stenosis and severe impediment to the bi-ventricular outflow as a result of supravalvular aortic and pulmonary artery stenosis predispose patients to sudden death. Patients with progressed arterial stenosis and severe stenosis are likely to require intervention to prevent serious complications. Rarely, imaging findings may precede clinical presentation, which allows the radiologist to participate in the patient care. However, to be more prudent, the radiologist must be accustomed to the imaging characteristics of WBS as well as the patient's clinical information, which could raise the suspicion of WBS. We performed a retrospective analysis of all the available images from patients diagnosed with WBS in last 4 years at our institution, and present key imaging findings along with a review of the literature to summarize the clinically relevant features as demonstrated by multidetector computed tomography in WBS. Cross-sectional imaging plays a vital role in the diagnosis of WBS cases with equivocal clinical features. MDCT evaluation of complex cardiovascular abnormalities of WBS including coronary artery disease is feasible with modern MDCT scanners and in the future, this approach could provide accurate information for planning, navigation, and noninvasive assessment of the secondary arterial changes in WBS and thus reducing the dependence upon invasive contrast catherization techniques.

Genetics of bipolar disorder

Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a "risk" allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are currently not fulfilled for common genomic variants in psychiatric disorders. Further work is clearly needed before genetic testing for common variants in psychiatric disorders should be established.