Gene variants associated with obstructive sleep apnea (OSA) in relation to sudden infant death syndrome (SIDS)

Early-onset pharyngeal airway collapse in infants: a retrospective single-center study

BACKGROUND

Early-onset pharyngeal airway collapse (PAC) in infants, which presents with onset within 6-months old is relatively rare. This disease has not been given enough attention in clinic. The aim of this study was to explore the clinical features, endoscopic findings and outcomes of early-onset PAC in infants.

METHODS

The children of PAC with onset within 6-months old were included. A retrospective study was conducted.

RESULTS

(1) Total 26 cases were included. The age of onset was neonatal period in 20 cases, 1 to 3-months old in 5 cases, and 4 to 6-months old in 1 case. (2) The main clinical manifestations were noisy breathing (26/26), suprasternal retraction (18/26), snoring (14/26) and hypoxic episode (13/26). (3) Based on the endoscopic findings, collapse at the retropalatal level was most common (24/26). (4) Twelve cases underwent pharyngolaryngeal CT examination, which revealed abnormal findings in 7 cases. (5) Fifteen cases were accompanied with the other airway malformations. (6) In the group with comorbidities of cerebral impairment or craniofacial abnormalities, 1 case was lost to follow up, 4 cases died, and 10 cases survived, in which 9 cases had neurodevelopmental disorders. In the group without comorbidities, 2 cases were lost to follow up, 9 cases survived, in which 1 case had neurodevelopmental disorders. The incidence of poor prognosis including death and neurodevelopmental disorders was significantly higher in the group with comorbidities than that without comorbidities (P<0.01). (7) An symptomatic improvement of PAC was found in the majority of the survived cases (18/19) with age.

CONCLUSIONS

Early-onset PAC in infants usually exhibits varying degrees of relief with age, whereas the cases with comorbidities had a poor prognosis.

A rare early-onset neonatal case of Birk-Barel syndrome presenting severe obstructive sleep apnea: a case report

Background

Birk-Barel syndrome, also known as KCNK9 imprinting syndrome, is a rare fertility disorder. And the main clinical manifestations include congenital hypotonic, craniofacial malformation, developmental delay, and intellectual disability. Generally, such patients could be diagnosed beyond the infant period. Moreover, the delayed diagnosis might lead to a poor prognosis of rehabilitation therapy. However, neonatal obstructive sleep apnea (OSA) was seldom reported in Birk-Barel syndrome. Here, we reported a severe neonatal OSA case induced by Birk-Barel syndrome, resulting in an early diagnosis with improved outcomes by integrative management.

Case presentation

The proband was a neonate presenting with recurrent severe OSA, with craniofacial deformity and congenital muscle hypotonia. Bronchoscopy examinations indicated a negative finding of pharyngeal and bronchus stenosis, while laryngomalacia had been observed. Whole exon sequencing demonstrated a c. 710C>A heterozygous variant resulting in a change of amino acid (p.A237D). This variant resulted in a change of amino acid sequence, affected protein features and changed splice site leading to a structural deformation in KCNK9 protein. This p.A237D variant also affected the crystal structure on the p.G129 site. Additionally, we used the mSCM tool to measure the free energy changes between wild-type and mutant protein, which indicated highly destabilizing (-2.622 kcal/mol).

Conclusion

This case report expands the understanding of Birk-Barel syndrome and indicates that OSA could serve as the on-set manifestation of Birk-Barel syndrome. This case emphasized genetic variants which were associated with severe neonatal OSA. Adequate WES assessment promotes early intervention and improves the prognosis of neurological disorders in young children.

Variants in genes encoding the SUR1-TRPM4 non-selective cation channel and sudden infant death syndrome (SIDS): potentially increased risk for cerebral edema

Increasing evidence suggests that brain edema might play an important role in the pathogenesis of sudden infant death syndrome (SIDS) and that variants of genes for cerebral water channels might be associated with SIDS. The role of the sulfonylurea receptor 1 (SUR1)-transient receptor potential melastatin 4 (TRPM4) non-selective cation channel in cerebral edema was demonstrated by extensive studies. Therefore, we hypothesized that variants at genes of the SUR1-TRPM4 channel complex might be linked to SIDS. Twenty-four polymorphisms in candidate genes involved in the SUR1-TRPM4 non-selective cation channel were investigated in 185 SIDS cases and 339 controls. One (rs11667393 in TRPM4) of these analyzed SNPs reached nominal significance regarding an association with SIDS in the overall analysis (additive model: p = 0.015, OR = 1.438, 95% CI = 1.074-1.925; dominant model: p = 0.036; OR = 1.468, 95% CI = 1.024-2.106). In the stratified analysis, further 8 variants in ABCC8 (encoding SUR1) or TRPM4 showed pronounced associations. However, none of the results remained significant after correction for multiple testing. This preliminary study has provided the first evidence for a genetic role of the SUR1-TRPM4 complex in the etiology of SIDS, and we suggest that our initial results should be evaluated by further studies.

Sudden infant death syndrome revisited: serotonin transporter gene, polymorphisms and promoter methylation

BACKGROUND

Based on findings in the brain stems of SIDS victims, the serotonin transporter (5-HTT) gene has been discussed to be associated with SIDS.

METHODS

In the largest study to date, we investigated the promoter length (5-HTTLPR) and intron 2 VNTR polymorphisms in 274 cases and 264 controls and the Ile425Val polymorphism in 65 cases and 64 controls. Moreover, the methylation of the internal promoter region was investigated in 35 cases and 14 controls.

RESULTS

For 5-HTTLPR, we observed a trend towards an association of allele L (58.8% vs. 53.4%) with SIDS and significant results were observed after stratifying for age, season at death, and prone position. Nevertheless, when pooling all published data, a significant association of allele L with SIDS is confirmed (p: 0.001). For the intron 2 VNTR polymorphism, no significant differences were observed. After pooling, a significant accumulation of the rare allele 9 was observed in SIDS (2.1% vs. 0.6%; p: 0.018). For the Ile425Val polymorphism, no differences were observed.

CONCLUSION

We conclude that genetic variation at this gene might be of some importance in SIDS. Epigenetic analysis of the internal promoter, however, revealed no influence on the relative risk to succumb to SIDS.

IMPACT

This is the largest study published up to now on 5-HTT gene polymorphisms and SIDS. Polymorphisms in the 5-HTT gene appear to contribute (although to a small degree) to the risk to die from SIDS. There is no evidence that a methylation of the promoter region is of impact for the etiology of SIDS.

Obstructive sleep apnea and associated factors among hypertensive patients attending a tertiary cardiac center in Tanzania: a comparative cross-sectional study

Background

There is mounting evidence for a reciprocal yet bidirectional association between sleep-disordered breathing and hypertension. Obstructive sleep apnea (OSA), a common cause of systemic hypertension is an independent risk factor for hypertension-related cardiovascular morbidity and mortality. In this comparative hospital-based cross-sectional study, we sought to explore the burden of obstructive sleep apnea and its associated risk factors among hypertensive patients attending Jakaya Kikwete Cardiac Institute.

Methodology

A total of 1974 individuals (i.e. 1289 hypertensive and 685 normotensives) were consecutively enrolled in this study. The Berlin questionnaire and Epworth Sleepiness Scale were utilized in the assessment of OSA and excessive daytime sleepiness (EDS) respectively. Logistic regression analyses were employed in the determination of associated factors for OSA.

Results

The mean age was 53.4 years and females constituted the large majority (60.4%) of participants. About three quarters (74.1%) of participants had excess body weight, 11.6% had diabetes, 8.0% had asthma and 18.6% had history of recurrent nasal congestion. Positive family history of snoring was reported by 43.1% of participants and 36.9% had a personal history of snoring. Persons with hypertension displayed a higher frequency (42.1%) of OSA compared to their normotensive counterparts (11.8%), p < 0.001. Multivariate logistic regression analyses revealed hypertension (OR 5.1, 95% CI 3.2-8.2, p < 0.001), diabetes mellitus (OR 2.2, 95% CI 1.3-3.5, p < 0.01), chronic nasal congestion (OR 1.6, 95% CI 1.1-2.5, p = 0.01), obesity (OR 2.4, 95% CI 1.8-3.3, p < 0.001), increased neck circumference (OR 2.7, 95% CI 1.2-6.4, p = 0.02), family history of snoring (OR 5.5, 95% CI 4.0-7.5, p < 0.001), and working > 8 h/24 h (OR 0.6, 95% CI 0.4-1.0, p = 0.03) to have an independent association for OSA. Furthermore, participants with hypertension displayed superior odds for OSA compared to their normotensive counterparts across all subgroup analyses.

Conclusion

OSA is considerably common among patients with hypertension in a tertiary health care setting in Tanzania. Positive family history of snoring was the strongest associated factor; however, excess body weight proved to be the strongest modifiable risk factor. In view of its pervasiveness, OSA should be an integral part of the medical evaluation in hypertensive individuals.