1004 Smith-<Magenis Syndrome (SMS) Circadian Abnormalities And Biological Rhythms

Introduction

SMS is a rare neurodevelopmental disorder that manifests with craniofacial abnormalities, behavioral disturbances, and a severe sleep disorder. It has been reported that many SMS patients have an inverted melatonin secretion pattern (peaking during the daytime) although a small minority have near normal patterns. The goal of this study was to better characterize the intra- and inter-patient variability of melatonin secretion patterns and investigate a potential relationship with sleep behavior in SMS patients.

Methods

In this observational study, sleep behaviors of patients (N=8, 1 female, ages: 7 - 35) with SMS were characterized through caretaker surveys. On 3 separate occasions, patients had hourly serum melatonin levels sampled for 36 hours. From these data, peak serum melatonin concentration and time of peak concentration were determined. Inter- and intra-patient variability was characterized by zero lag correlation of the melatonin concentration timeseries across and within patients, respectively. The relationship between peak melatonin concentration, peak time, and sleep latency was analyzed by a generalized linear model, GLM.

Results

Peak melatonin concentrations varied across SMS patients with a range of 3.55pg/ml - 49.65pg/ml (mean 14.18 ± 15.19pg/ml). Time of peak melatonin concentrations ranged from 0400h-2100h (mean 1422 ± 6h). Correlation coefficients characterizing intra-patient variability ranged from -0.0098 to 0.89 (mean 0.55 ± 0.2533). Correlation coefficients characterizing inter-patient variability ranged from -0.75 to 0.79 (mean of 0.18 ± 0.52). Sleep latency ranged from 8.4min - 36.35min (mean of 21.99 ± 9.77 min). GLM analysis demonstrated a significant, positive effect of peak time with sleep latency (p=0.022).

Conclusion

Consistent with previous findings, our study confirms that SMS patients have abnormal circadian rhythms. Our work extends this body of literature by demonstrating a significant degree of inter-patient variability with relatively stable intra-patient variability. Preliminary evidence suggests that the timing of melatonin peak may be related to sleep onset latency.

Support

This work was supported by Vanda Pharmaceuticals Inc.

1161 Tasimelteon Shows Persistence Of Efficacy In Improving Sleep Disturbances In Patients With Smith-Magenis Syndrome (SMS) In Open-Label Extension Study

Introduction

Smith-Magenis Syndrome (SMS) is a rare (1/15,000 - 25,000 births) neurodevelopmental disorder resulting from an interstitial deletion of chromosome 17p11.2, or from a point mutation in the RAI1 gene. Severe sleep disorder is almost universal in patients with SMS and poses a significant challenge to patients and their families. Tasimelteon improved sleep symptoms in a randomized, double-blind, two-period, crossover study; and here we show that this effect persists for up to four years in an open-label extension. To our knowledge, this is the largest interventional study of SMS patients to date.

Methods

Following the 4-week crossover study, all eligible participants had the option to enroll in an open-label extension. 31/39 (79.4%) of all individuals who participated in the efficacy study have continued on tasimelteon treatment. Participants in the open-label extension provided daily diary sleep quality (DDSQ), and daily diary total sleep time (DDTST) measures via parental post sleep questionnaire and characterized behavior using the Aberrant Behavior Checklist (ABC).

Results

In the open-label extension, tasimelteon continued to show improvement in the primary endpoints of 50% worst sleep quality (mean = 0.7, SD = 0.94) and 50% worst total nighttime sleep duration (mean = 53.3, SD = 59.01) when compared to baseline. Tasimelteon also improved overall sleep quality (mean=0.7, SD=0.83) and overall total nighttime sleep duration (mean = 51.9, SD=53.03). ABC scores also improved with tasimelteon (mean= -16.3, SD = 15.82).

Conclusion

Tasimelteon continues to demonstrate persistence in efficacy (longest approximately 4 years) with similar magnitudes observed in the 4-week crossover study for sleep quality and total sleep time. Interestingly, daytime behavior also demonstrates long-term improvement in patients with SMS treated with tasimelteon. These results further confirm tasimelteon as a novel therapy for the treatment of sleep disorders in patients with SMS and may provide benefit for behavioral symptoms.

Support

This work was supported by Vanda Pharmaceuticals Inc.

Correlation of age-of-onset of Atopic Dermatitis with Filaggrin loss-of-function variant status

The genetic background of Atopic Dermatitis (AD) with chronic pruritus is complex. Filaggrin (FLG) is an essential gene in the epidermal barrier formation s. Loss-of-function (LOF) variants in FLG associated with skin barrier dysfunction constitute the most well-known genetic risk factor for AD. In this study, we focused on the frequency and effect of FLG loss-of-function variants in association with self-reported age-of-onset of AD. The dataset consisted of 386 whole-genome sequencing (WGS) samples. We observe a significant association between FLG LOF status and age-of-onset, with earlier age of onset of AD observed in the FLG LOF carrier group (p-value 0.0003, Wilcoxon two-sample test). We first tested this on the two most prevalent FLG variants. Interestingly, the effect is even stronger when considering all detected FLG LOF variants. Having two or more FLG LOF variants associates with the onset of AD at 2 years of age. In this study, we have shown enrichment of rare variants in the EDC region in cases compared with controls. Age-of-onset analysis shows not only the effect of the FLG and likely EDC variants in terms of the heightened risk of AD, but foremost enables to predict early-onset, lending further credence to the penetrance and causative effect of the identified variants. Understanding the genetic background and risk of early-onset is suggestive of skin barrier dysfunction etiology of AD with chronic pruritus