Sleep and sleep disorders in rare hereditary diseases: a reminder for the pediatrician, pediatric and adult neurologist, general practitioner, and sleep specialist

Do metabolic deficits contribute to sleep disruption in monogenic intellectual disability syndromes?

Intellectual disability is defined as limitations in cognitive and adaptive behavior that often arise during development. Disordered sleep is common in intellectual disability and, given the importance of sleep for cognitive function, it may contribute to other behavioral phenotypes. Animal models of intellectual disability, in particular of monogenic intellectual disability syndromes (MIDS), recapitulate many disease phenotypes and have been invaluable for linking some of these phenotypes to specific molecular pathways. An emerging feature of MIDS, in both animal models and humans, is the prevalence of metabolic abnormalities, which could be relevant for behavior. Focusing on specific MIDS that have been molecularly characterized, we review sleep, circadian, and metabolic phenotypes in animal models and humans and propose that altered metabolic state contributes to the abnormal sleep/circadian phenotypes in MIDS.

Sleep problems in children with Angelman Syndrome: The effect of a behavioral intervention program

BACKGROUND & AIMS

The aim of this study was to investigate the effect of a behavioral intervention on sleep problems, which are significant and an unmet clinical need in children with Angelman Syndrome (AS).

METHODS & PROCEDURES

Children (2-18 years) with AS and sleep problems were randomized to a behavioral intervention program or a control group. Intervention consisted of a standardized program including home visits, psycho-education, feedback based on direct observation of bedtime routine and video footage of the night and behavioral treatment techniques by a behavioral therapist. Change in sleep duration (primary) and parental sleep, nighttime visits, sleep hygiene, daytime behavior, parental stress and quality of life (secondary) were assessed post-intervention and at follow-up using questionnaires, diary, actigraphy and videosomnography.

OUTCOMES & RESULTS

The groups, 9 children in each, did not differ at baseline. We found a significant effect of intervention on wake after sleep onset with classical statistical analysis (videosomnography). With single case analysis we found a positive effect on total sleep time (diary and actigraphy) and wake after sleep onset (diary) with a persistent effect on total sleep time (actigraphy) and wake after sleep onset (diary). On secondary outcome there was a significant and persistent effect on sleep hygiene and several quality of life domains.

CONCLUSIONS & IMPLICATIONS

Behavioral intervention has a positive and persistent effect on sleep problems in children with AS. We advise psycho-education for all parents and use of videosomnography for both evaluation of and feedback on sleep behavior patterns, individual behavioral advice and specific behavioral techniques for children with sleep problems.

Management of CLN1 Disease: International Clinical Consensus

BACKGROUND

CLN1 disease (neuronal ceroid lipofuscinosis type 1) is a rare, genetic, neurodegenerative lysosomal storage disorder caused by palmitoyl-protein thioesterase 1 (PPT1) enzyme deficiency. Clinical features include developmental delay, psychomotor regression, seizures, ataxia, movement disorders, visual impairment, and early death. In general, the later the age at symptom onset, the more protracted the disease course. We sought to evaluate current evidence and to develop expert practice consensus to support clinicians who have not previously encountered patients with this rare disease.

METHODS

We searched the literature for guidelines and evidence to support clinical practice recommendations. We surveyed CLN1 disease experts and caregivers regarding their experiences and recommendations, and a meeting of experts was conducted to ascertain points of consensus and clinical practice differences.

RESULTS

We found a limited evidence base for treatment and no clinical management guidelines specific to CLN1 disease. Fifteen CLN1 disease experts and 39 caregivers responded to the surveys, and 14 experts met to develop consensus-based recommendations. The resulting management recommendations are uniquely informed by family perspectives, due to the inclusion of caregiver and advocate perspectives. A family-centered approach is supported, and individualized, multidisciplinary care is emphasized in the recommendations. Ascertainment of the specific CLN1 disease phenotype (infantile-, late infantile-, juvenile-, or adult-onset) is of key importance in informing the anticipated clinical course, prognosis, and care needs. Goals and strategies should be periodically reevaluated and adapted to patients' current needs, with a primary aim of optimizing patient and family quality of life.

De Novo KAT5 Variants Cause a Syndrome with Recognizable Facial Dysmorphisms, Cerebellar Atrophy, Sleep Disturbance, and Epilepsy

KAT5 encodes an essential lysine acetyltransferase, previously called TIP60, which is involved in regulating gene expression, DNA repair, chromatin remodeling, apoptosis, and cell proliferation; but it remains unclear whether variants in this gene cause a genetic disease. Here, we study three individuals with heterozygous de novo missense variants in KAT5 that affect normally invariant residues, with one at the chromodomain (p.Arg53His) and two at or near the acetyl-CoA binding site (p.Cys369Ser and p.Ser413Ala). All three individuals have cerebral malformations, seizures, global developmental delay or intellectual disability, and severe sleep disturbance. Progressive cerebellar atrophy was also noted. Histone acetylation assays with purified variant KAT5 demonstrated that the variants decrease or abolish the ability of the resulting NuA4/TIP60 multi-subunit complexes to acetylate the histone H4 tail in chromatin. Transcriptomic analysis in affected individual fibroblasts showed deregulation of multiple genes that control development. Moreover, there was also upregulated expression of PER1 (a key gene involved in circadian control) in agreement with sleep anomalies in all of the individuals. In conclusion, dominant missense KAT5 variants cause histone acetylation deficiency with transcriptional dysregulation of multiples genes, thereby leading to a neurodevelopmental syndrome with sleep disturbance, cerebellar atrophy, and facial dysmorphisms, and suggesting a recognizable syndrome.

Uncovering sleep in young males with Duchenne muscular dystrophy

OBJECTIVES

Sleep health in rare disease is often overlooked due to the complex nature of the disease. For males with Duchenne muscular dystrophy, sleep assessment is typically focused on pulmonary function and identification of sleep disordered breathing. Unfortunately for young boys with Duchenne muscular dystrophy, sleep assessment is often neglected, resulting in a dearth of knowledge on sleep health in this population. This study describes sleep quantity and quality in both younger (4-9 years) and older (10-17 years) males with Duchenne muscular dystrophy (n = 19) and compares these characteristics with sleep characteristics of unaffected peers (n = 17).

METHODS

This study was a longitudinal, observational study. Sleep measures were collected using the parent-proxy Children's Sleep Habits Questionnaire-Abbreviated version and objective sleep measures from actigraphy (sleep efficiency, awakenings, and awakening duration) over 30 days for all participants. Means and standard deviations were examined, and effect sizes were computed to quantify the magnitude of difference between the Duchenne muscular dystrophy and unaffected groups.

RESULTS

Overall, boys with Duchenne muscular dystrophy were found to experience worse sleep than their unaffected peers as measured by parent report and actigraphy. Effect sizes of both measures demonstrated moderate to large magnitudes of difference in many of the sleep variables. Parents of boys with Duchenne muscular dystrophy reported higher scores (indicating worse sleep) in all subsections and total score of the Children's Sleep Habits Questionnaire - Abbreviated version. Actigraphy data indicated that the Duchenne muscular dystrophy group had lower percent sleep efficiency, more night awakenings and longer duration of night awakenings than their unaffected peers.

CONCLUSION

Our findings offer a novel look into sleep in young boys with Duchenne muscular dystrophy. Both parent-report and actigraphy data indicate poor sleep health in this population compared with age-matched unaffected peers. Actigraphy was found to align with parent-report of sleep in this population, supporting the use of these two different ways to measure sleep in Duchenne muscular dystrophy. Results from this study should encourage clinicians and researchers alike to further explore sleep and its impact on disease in young boys with Duchenne muscular dystrophy.

Obstructive Sleep Apnea in Jacobsen Syndrome

Purpose

Many congenital disorders are associated with an elevated risk of obstructive sleep apnea due to craniofacial abnormalities, hypotonia, and obesity. We describe a male with an 11q deletion (Jacobsen syndrome) with obstructive sleep apnea.

Report of Case

The patient was diagnosed with severe obstructive sleep apnea, but was unable to adhere to positive airway pressure therapy due to mask discomfort.

Discussion

Obstructive sleep apnea is common in many congenital disorders. Implications for cognitive functioning, as well as the potential for cognitive improvements following treatment are discussed. Screening polysomnography may be indicated in patients with Jacobsen syndrome given their high likelihood of obstructive sleep apnea.

Case Report of Pediatric Channelopathies With UNC80 and KCNJ11 Mutations Having Abnormal Respiratory Control Treated With Positive Airway Pressure Therapy

ABSTRACT

There have been no published reports of central respiratory control abnormalities in pediatric patients with UNC80 or KCNJ11 mutations which cause neurologic channelopathies. We describe an 8-year-old male with a pathogenic UNC80 mutation, intellectual disability, hypotonia and epilepsy with severe central sleep apnea (213.5 events/h) on polysomnography (PSG). We also describe a 20-month-old female with a KCNJ11 mutation, neonatal diabetes and developmental delay who had severe central sleep apnea (131.1 events/h). Both patients had irregular respiratory patterns during sleep and wakefulness and were placed on empiric bilevel positive airway pressure therapy, which was well tolerated with resolution of abnormal respiratory control and hypercapnia. Patients with UNC80 and KCNJ11 gene mutations may have abnormal respiratory rhythm during sleep and wakefulness, mirroring animal models. We recommend routine PSG tests and further investigation into the respiratory control of patients with pediatric channelopathies involved in chemoreceptor function or central integration of respiratory control.

Altered sleep patterns in patients with non-functional GHRH receptor

OBJECTIVES

GH-releasing hormone (GHRH) exerts hypnotic actions increasing the non-rapid eye movement (NREM) sleep. Conversely, GH stimulates the REM sleep. GH deficiency (GHD) often leads to sleep problems, daytime fatigue and reduced quality of life (QoL). GHD may be due to lack of hypothalamic GHRH or destruction of somatotroph cells. We have described a cohort with isolated GHD (IGHD) due to GHRH resistance caused by a homozygous null mutation (c.57 + 1G > A) in the GHRH receptor gene. They have normal QoL and no obvious complaints of chronic tiredness. The aim of this study was to determine the sleep quality in these subjects.

METHODS

A cross-sectional study was carried out in 21 adult IGHD subjects, and 21 age- and gender-matched controls. Objective sleep assessment included polygraphic records of the awake, stages NREM [N1 (drowsiness), N2 and N3 (already sleeping)] and REM (R). Subjective evaluation included the Pittsburgh Sleep Quality Index, the Insomnia Severity Index and the Epworth Sleepiness Scale.

RESULTS

IGHD subjects showed a reduction in sleep efficiency (P = 0.007), total sleep time (P = 0.028), duration of N2 and R in minutes (P = 0.026 and P = 0.046 respectively), but had increased duration and percentage of N1 stage (P = 0.029 and P = 0.022 respectively), wake (P = 0.007) and wake-time after sleep onset (P = 0.017). There was no difference in N3 or in sleep quality questionnaire scores.

CONCLUSION

Patients with IGHD due to GHRH resistance exhibit objective reduction in the sleep quality, with changes in NREM and REM sleep, with no detectable subjective consequences. GHRH resistance seems to have a preponderant role over GHD in the sleep quality of these subjects.