Urinary Biomarkers as a Proxy for Congenital Central Hypoventilation Syndrome Patient Follow-Up.

Congenital Central Hypoventilation Syndrome (CCHS) is a rare genetic disorder of the autonomic nervous system and in particular of the respiratory control during sleep. No drug therapy is, to date, available; therefore, the survival of these patients depends on lifelong ventilatory support during sleep. Reactive oxygen species (ROS)-induced oxidative stress is a recognized risk factor involved in the pathogenesis of several chronic diseases. Therefore, monitoring systemic oxidative stress could provide important insights into CCHS outcomes. Because ROS-induced oxidative products are excreted as stable metabolites in urine, we performed an HPLC-MS/MS analysis for the quantitative determination of the three main representative oxidative biomarkers (i.e., diY, MDA, and 8-OHdG) in the urine of CCHS patients. Higher levels of urinary MDA were found in CCHS patients compared with age-matched control subjects. The noteworthy finding is the identification of urinary MDA as relevant biomarker of systemic oxidative status in CCHS patients. This study is a concise and smart communication about the impact that oxidative stress has in CCHS, and suggests the monitoring of urinary MDA levels as a useful tool for the management of these patients.

Generation of two hiPSC lines (UMILi027-A and UMILi028-A) from early and late-onset Congenital Central hypoventilation Syndrome (CCHS) patients carrying a polyalanine expansion mutation in the PHOX2B gene.

Congenital Central Hypoventilation Syndrome (CCHS) is a rare disorder of the autonomic nervous system (ANS), characterized by inadequate control of autonomic ventilation and global autonomic dysfunction. Heterozygous polyalanine repeat expansion mutations in exon 3 of the transcription factor Paired-like homeobox 2B (PHOX2B) gene occur in 90% of CCHS cases. In this study, we describe the generation and characterization of two human induced pluripotent stem cell (hiPSC) lines from female CCHS patients carrying a heterozygous + 5 alanine expansion mutation. The generated iPSC lines show a normal karyotype, express pluripotency markers and are able to differentiate into the three germ layers.

A Common 3'UTR Variant of the PHOX2B Gene Is Associated With Infant Life-Threatening and Sudden Death Events in the Italian Population.

Heterozygous mutations in the Paired like homeobox 2b (PHOX2B) gene are causative of congenital central hypoventilation syndrome (CCHS), a rare monogenic disorder belonging to the family of neurocristopathies and due to a defective development of the autonomic nervous system. Most patients manifest sudden symptoms within 1 year of birth, mainly represented by central apnea and cyanosis episodes. The sudden appearance of hypoxic manifestations in CCHS and their occurrence during sleep resemble two other unexplained perinatal disorders, apparent life-threatening event (ALTE) and sudden and unexpected infant death (SUID), among which the vast majority is represented by sudden infant death syndrome (SIDS). Differently from CCHS, characterized by Mendelian autosomal dominant inheritance, ALTE and SIDS are complex traits, where common genetic variants, together with external factors, may exert an additive effect with symptoms likely manifesting only over a "threshold." Given the similarities observed among the three abovementioned perinatal disorders, in this work, we have analyzed the frequency of PHOX2B common variants in two groups of Italian idiopathic ALTE (IALTE) and SUIDs/SIDS patients. Here, we report that the c*161G>A (rs114290493) SNP of the 3'UTR PHOX2B (i) became overrepresented in the two sets of patients compared to population matched healthy controls, and (ii) associated with decreased PHOX2B gene expression, likely mediated by miR-204, a microRNA already known to bind the 3'UTR of the PHOX2B gene. Overall, these results suggest that, at least in the Italian population, the SNP c*161G>A (rs114290493) does contribute, presumably in association with others mutations or polymorphisms, to confer susceptibility to sudden unexplained perinatal life-threatening or fatal disorders by increasing the effect of miR-204 in inducing PHOX2B expression down-regulation. However, these are preliminary observations that need to be confirmed on larger cohorts to achieve a clinical relevance.

Guidelines for diagnosis and management of congenital central hypoventilation syndrome.

BACKGROUND: Congenital Central Hypoventilation Syndrome (CCHS) is a rare condition characterized by an alveolar hypoventilation due to a deficient autonomic central control of ventilation and a global autonomic dysfunction. Paired-like homeobox 2B (PHOX2B) mutations are found in most of the patients with CCHS. In recent years, the condition has evolved from a life-threatening neonatal onset disorder to include broader and milder clinical presentations, affecting children, adults and families. Genes other than PHOX2B have been found responsible for CCHS in rare cases and there are as yet other unknown genes that may account for the disease. At present, management relies on lifelong ventilatory support and close follow up of dysautonomic progression. BODY: This paper provides a state-of-the-art comprehensive description of CCHS and of the components of diagnostic evaluation and multi-disciplinary management, as well as considerations for future research. CONCLUSION: Awareness and knowledge of the diagnosis and management of this rare disease should be brought to a large health community including adult physicians and health carers.

The multiagency approach to Sudden Unexpected Infant Deaths (SUID): eleven years' experience in the Tuscany Region.

BACKGROUND: The Sudden Unexpected Infant Death Syndrome (SUID) is one of the leading causes of mortality in the first year of life. The aim of this work was the retrospective evaluation of the incidence of SUID and the effectiveness of the multiagency approach to this phenomenon in the Tuscany Region. METHODS: Data were obtained from the regional registry of SUID cases in the period 2009-2019. The registry contains both sudden unexpected deaths in the first week of life (Sudden Unexpected Early Neonatal Deaths - SUEND), and those occurring after the first week up to 1 year of age (SUID). RESULTS: In this timeframe a total of 73 sudden unexpected deaths occurred in our region; 32 were Unexplained (i.e. Sudden Infant Death Syndrome - SIDS), 24 Explained, 10 Undetermined, and 7 SUEND. Autopsies were performed in 91% of cases, and in 95% of these by three groups of selected pathologists according to our protocol. We found a low incidence of SUID (0.21 ‰), and SIDS deaths accounted for 0.1‰ of live births (48% of cases) with a high prevalence of infants of non-Italian ethnicity (38% of cases). Bereaved families were able to receive psychological support from mental health professionals and have contact with the family association, Seeds for SIDS. Audits were organized when post-mortem examinations were not carried out or carried out incorrectly in procedural terms, and when the diagnosis was particularly uncertain. CONCLUSIONS: This paper first provides data on SUID mortality based on complete post-mortems in an Italian region. According to these findings we can state that our approach is effective both in terms of correctly performed autopsies and support for bereaved families. Future efforts are necessary to further reduce the incidence of SUID especially among non- Italian infants. An improvement action is also recommended for ensuring a more accurate and consistent picture of the circumstances of death. The final approval of the National Protocol for the management of SUID cases is therefore strongly advocated in order to improve surveillance in this specific field and abolish disparities among the Italian regions.

Can we still do something-and what? - for a seemingly missing syndrome?: "Yes we can".

In this letter, the authors compare the incidence of SUDI and SIDS in the Tuscany Region to the incidence reported by Campi and Bonati in their paper "Can we still do something-and what?- for a seemingly missing syndrome?" that was recently published in this journal. The Tuscany data are directly gathered from the autopsies while the others from the death certificates that are often not reilable, thus causing an understimation of the phenomenon. The real picture of the extent of SIDS is crucial to evaluate the effectiveness of back to sleep campaigns.

Apparent Life-Threatening Events (ALTE): Italian guidelines.

Five years after the first edition, we have revised and updated the guidelines, re-examining the queries and relative recommendations, expanding the issues addressed with the introduction of a new entity, recently proposed by the American Academy of Pediatrics: BRUE, an acronym for Brief Resolved Unexplained Events. In this manuscript we will use the term BRUE only to refer to mild, idiopathic cases rather than simply replace the acronym ALTE per se.In our guidelines the acronym ALTE is used for severe cases that are unexplainable after the first and second level examinations.Although the term ALTE can be used to describe the common symptoms at the onset, whenever the aetiology is ascertained, the final diagnosis may be better specified as seizures, gastroesophageal reflux, infection, arrhythmia, etc. Lastly, we have addressed the emerging problem of the so-called Sudden Unexpected Postnatal Collapse (SUPC), that might be considered as a severe ALTE occurring in the first week of life.

Sleeping problems in mothers and fathers of patients suffering from congenital central hypoventilation syndrome.

PURPOSE: Advanced medical technology has resulted in an increased survival rate of children suffering from congenital central hypoventilation syndrome. After hospitalization, these technology-dependent patients require special home care for assuring ventilator support and the monitoring of vital parameters mainly during sleep. The daily challenges associated with caring for these children can place primary caregivers under significant stress, especially at night. Our study aimed at investigating how this condition affects mothers and fathers by producing poor sleep quality, high-level diurnal sleepiness, anxiety, and depression. METHODS: The study included parents of 23 subjects with congenital central hypoventilation syndrome and 23 healthy subjects. All parents filled out the Pittsburgh Sleep Quality Index (PSQI) questionnaire, Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI-II), and Beck Anxiety Inventory (BAI). RESULTS: A comparison between the two groups showed that parents of patients had poorer sleep quality, greater sleepiness, and higher BDI-II scores compared to that of parents of healthy subjects (respectively, PSQI score 6.5 vs 3.8, ESS score 6.2 vs 4.3, BDI-II score 8.4 vs 5.7). Specifically, mothers of patients showed poorer sleep quality and higher BDI-II scores compared to that of mothers of controls (respectively, PSQI score 7.5 vs 3.8, BDI-II score 9.3 vs 5.9), whereas fathers of patients showed greater levels of sleepiness with respect to fathers of healthy children (respectively, ESS score 6.8 vs 4.0). These differences emerged in parents of younger children. CONCLUSIONS: Congenital central hypoventilation syndrome impacts the family with different consequences for mothers and fathers. Indeed, while the patients' sleep is safeguarded, sleeping problems may occur in primary caregivers often associated with other psychological disorders. Specifically, this disease affects sleep quality and mood in the mothers and sleepiness levels in the fathers.

Telemonitoring for infants at risk of apnoea, bradycardia and hypoxaemia: transmission of data improves the family compliance during home monitoring.

We evaluated the compliance of families using telemonitoring and families using conventional home monitoring in infants at risk of apnoea, bradycardia and hypoxaemia. Families who used the telemedicine system could perform the remote data transmission from their home. Families who used the conventional system had to come to the regional centre to download the cardiorespiratory traces captured by the monitor. A total of 175 patients examined at the Regional Centre for Sudden Infant Death Syndrome (SIDS) in Florence were included in the 5-year study. Good compliance was defined as an average daily use of 10 hours or more; insufficient compliance was defined as an average daily use of less than 10 hours. The Centre analysed 612 data downloads, 339 from the telemedicine system and 273 from the conventional system. This represented a total of 105,061 hours of data during 12,862 days of home monitoring. The compliance of families who used the telemedicine system was significantly higher than that of families who used the conventional system. Of the 105 families who used the conventional system, 50 (48%) were good compliers. Of the 70 families who used the telemedicine system, 49 (70%) were good compliers. Telemedicine was associated with a significant improvement in the compliance of families using cardiorespiratory monitors.

Fog-induced cough with impaired respiratory sensation in congenital central hypoventilation syndrome.

RATIONALE: Congenital central hypoventilation syndrome (CCHS) is a genetic disorder mainly characterized by failure of automatic control of breathing, causing alveolar hypoventilation. Little is known regarding cough in CCHS. Parental reports indicate that patients cough normally during airway infections; however, previous studies have demonstrated no cough response to fog inhalation. OBJECTIVES: To evaluate the sensory and motor components of cough, respiratory sensations, and changes in ventilation evoked by fog inhalation in children with CCHS and in sex- and age-matched control subjects. METHODS: Cough threshold was measured and cough intensity was indexed in terms of cough peak expiratory flow and integrated abdominal electromyographic activity. The pattern of breathing was recorded by inductive plethysmography. Respiratory sensations were also investigated. MEASUREMENTS AND MAIN RESULTS: All control subjects and six of seven patients coughed in response to fog inhalation. The seventh coughed with citric acid aerosol inhalation. Cough threshold values were similar in control subjects (range, 0.40-2.22 ml/min) and patients (range, 0.40-3.26 ml/min). Mean values of cough peak expiratory flow and of integrated abdominal electromyographic activity-related variables during coughing were also similar and corresponded to 80% of those recorded during maximum voluntary cough. Cough appearance was preceded by respiratory sensations and increases (P < 0.01) in ventilation in the control subjects but not in the patients. CONCLUSIONS: Children with CCHS have normal cough threshold and motor responses to fog inhalation. However, the lack of respiratory sensations and the likely related ventilatory changes typically elicited by tussigenic fog concentrations suggest a neural sensory deficit that may increase the risk of respiratory disease in these patients.

Cough in children with congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is defined as failure of the chemical (autonomic) control of breathing causing alveolar hypoventilation in the absence of pulmonary, cardiac, neuromuscular or patent brainstem lesions. Hypoventilation is predominant in non-rapid-eye-movement sleep, during which breathing is primarily under chemical control. Failure of the central integration of chemosensory inputs is proposed as the putative defect. A genetic basis for CCHS is supported by lines of evidence. In some diseases of the central nervous system there is more or less complete depression of the cough reflex, whereas spontaneous ventilation is generally preserved. Little is known regarding cough in CCHS patients. Parents consistently report that their children cough 'normally' during airway infections; in contrast, experimental lines of evidence suggest that CCHS children lack a cough response following inhalation of a tussigenic agent. Although several factors may account for the discrepancy, the possibility of a weakened or even absent cough reflex remains to be fully ascertained. Conceivably, a defective cough reflex, in conjunction with the well established lack of perception of respiratory discomfort, might result in an increased risk of potentially serious respiratory complications in CCHS patients.

Mutational analysis of the RNX gene in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is a rare syndrome characterized by failure of autonomic respiratory control, often presenting with other dysfunctions of the autonomic nervous system. Segregation analysis suggested a complex model of inheritance with a major locus involved. Disruption of the Rnx gene, a member of the Hox11 family of homeobox genes, in embryonic stem cells produced mice showing a phenotype similar to CCHS. Based on this observation, we have carried out mutation screening of the RNX gene in a set of 13 patients affected with CCHS, 2 of whom showing association with Hirschsprung disease. Single-strand conformational polymorphism analysis and direct sequencing of the whole coding portion of the RNX gene and of 1,311 bp of 5' flanking region were performed. No sequence variant was identified, with the exception of a private nucleotide change at position -874 bp from the ATG codon in two siblings affected with isolated CCHS. A functional test, performed by using the luciferase gene reporter system, has not shown any significant difference in the activity of the promoter region carrying this latter nucleotide change with respect to the wild-type allele. We conclude that RNX, and presumably its expression, are not altered in our index cases of CCHS.