Neuroimaging and Pathology Findings Associated With Rapid Onset Obesity, Hypothalamic Dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) Syndrome

Adipsic hypernatremia with marked hyperprolactinemia and GH deficiency in a 9-year-old boy

Adipsic hypernatremia is typically caused by congenital dysplasia of the hypothalamus and pituitary or brain tumors. However, cases of adipsic hypernatremia without underlying organic abnormalities are rare, and some cases have been reported to be complicated by hypothalamic-pituitary dysfunction. The patient in this case was a 9-yr-old boy who was referred to our hospital because of hypernatremia. His growth chart revealed that he had rapidly become obese since infancy, with growth retardation since the age of seven. His hands and feet were very cold, and he had erythema on his abdomen, indicating possible autonomic dysregulation due to hypothalamic dysfunction. Several hormone load tests showed severe GH deficiency (GHD) and marked hyperprolactinemia (peak: 302.8 ng/mL). Magnetic resonance imaging revealed no organic abnormalities in the hypothalamus and pituitary gland. GH replacement therapy was initiated. Although his growth rate improved, obesity persisted. To the best of our knowledge, this is the first report of adipsic hypernatremia without organic intracranial abnormalities that was treated with GH. Moreover, the patient's prolactin levels were higher than those reported in previous studies. In conclusion, adipsic hypernatremia requires the evaluation of pituitary function and appropriate therapeutic interventions.

High-Titer Anti-ZSCAN1 Antibodies in a Toddler Clinically Diagnosed with Apparent Rapid-Onset Obesity with Hypothalamic Dysfunction, Hypoventilation, and Autonomic Dysregulation Syndrome

Severe obesity in young children prompts for a differential diagnosis that includes syndromic conditions. Rapid-Onset Obesity with Hypothalamic Dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) syndrome is a potentially fatal disorder characterized by rapid-onset obesity associated with hypoventilation, neural crest tumors, and endocrine and behavioral abnormalities. The etiology of ROHHAD syndrome remains to be established, but recent research has been focusing on autoimmunity. We report on a 2-year-old girl with rapid-onset obesity during the first year of life who progressed to hypoventilation and encephalitis in less than four months since the start of accelerated weight gain. The patient had a high titer of anti-ZSCAN1 antibodies (348; reference range < 40), and the increased values did not decline after acute phase treatment. Other encephalitis-related antibodies, such as the anti-NDMA antibody, were not detected. The rapid progression from obesity onset to central hypoventilation with encephalitis warns about the severe consequences of early-onset ROHHAD syndrome. These data indicate that serial measurements of anti-ZSCAN1 antibodies might be useful for the diagnosis and estimation of disease severity. Further research is needed to determine whether it can predict the clinical course of ROHHAD syndrome and whether there is any difference in antibody production between patients with and without tumors.

Anti-ZSCAN1 Autoantibodies Are a Feasible Diagnostic Marker for ROHHAD Syndrome Not Associated with a Tumor

Recent studies have reported the presence of autoantibodies against zinc finger and SCAN domain-containing protein 1 (ZSCAN1) in the sera of patients with rapid-onset obesity with hypoventilation, hypothalamic and autonomic dysregulation (ROHHAD) syndrome associated with neuroendocrine tumors, suggesting immunologic and paraneoplastic processes as the pathologic underpinnings. Moreover, several hypothalamic regions, including the subfornical organ (SFO), were reported to exhibit antibody reactivity in a patient with ROHHAD syndrome not associated with a tumor. Whether ROHHAD syndrome not associated with a tumor is associated with anti-ZSCAN1 autoantibodies remains unclear. We used a comprehensive protein array analysis to identify candidate molecules in the sera of patients with ROHHAD syndrome and identified ZSCAN1 as a target antigen. We also found that ZSCAN1 was co-expressed at the site of antibody reactivity to the IgG in the patient serum observed in mouse SFOs and an enzyme-linked immunosorbent assay showed that >85% of the patients with ROHHAD syndrome were positive for anti-ZSCAN1 autoantibodies. These results suggest anti-ZSCAN1 autoantibodies as a feasible diagnostic marker in ROHHAD syndrome regardless of the presence of a tumor.

ROHHAD syndrome spectrum in an adult: a possible new variant

This case report describes for the first time the evolution of a mature patient with all the diagnostic criteria for ROHHAD syndrome. It shows a rare case of central alveolar hypoventilation with hypothalamic impairment, dysautonomia and rapid weight gain. https://bit.ly/49AN3Vv.

Whole genome sequencing in ROHHAD trios proved inconclusive: what's beyond?

Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation (ROHHAD) is a rare, life-threatening, pediatric disorder of unknown etiology, whose diagnosis is made difficult by poor knowledge of clinical manifestation, and lack of any confirmatory tests. Children with ROHHAD usually present with rapid onset weight gain which may be followed, over months or years, by hypothalamic dysfunction, hypoventilation, autonomic dysfunction, including impaired bowel motility, and tumors of neural crest origin. Despite the lack of evidence of inheritance in ROHHAD, several studies have been conducted in recent years that have explored possible genetic origins, with unsuccessful results. In order to broaden the search for possible genetic risk factors, an attempt was made to analyse the non-coding variants in two trios (proband with parents), recruited in the Gaslini Children's Hospital in Genoa (Italy). Both patients were females, with a typical history of ROHHAD. Gene variants (single nucleotide variants, short insertions/deletions, splice variants or in tandem expansion of homopolymeric tracts) or altered genomic regions (copy number variations or structural variants) shared between the two probands were searched. Currently, we have not found any potentially pathogenic changes, consistent with the ROHHAD clinical phenotype, and involving genes, regions or pathways shared between the two trios. To definitively rule out the genetic etiology, third-generation sequencing technologies (e.g., long-reads sequencing, optical mapping) should be applied, as well as other pathways, including those associated with immunological and autoimmune disorders, should be explored, making use not only of genomics but also of different -omic datasets.

Blood Lymphocyte Subsets and Proinflammatory Cytokine Profile in ROHHAD(NET) and non-ROHHAD(NET) Obese Individuals

Context

Rapid-onset obesity with central hypoventilation, hypothalamic dysfunction, and autonomic dysregulation with neural crest tumors (ROHHAD-NET) syndrome pathophysiology remains elusive. Acquired neuroimmunological dysfunction has been proposed as a possible pathogenetic pathway.

Objective

The aim of our study was to characterize lymphocyte subpopulations subsets in peripheral blood (PB) and to evaluate a panel of proinflammatory cytokines/chemokines in ROHHAD(NET) patients vs controls.

Methods

We included 11 ROHHAD(NET) patients, 7 ROHHAD and 4 ROHHAD-NET, selected by clinical criteria. Controls were 11 simple obese children, matched for age and sex. Flow cytometric analysis and enzyme-linked immunosorbent assay were performed on PB and serum samples of the 2 groups.

Results

Analysis revealed that T lymphocytes are significantly increased in ROHHAD(NET) patients (P = .04) with a prevalence of CD4-T cells (P = .03) and a lower number of activated CD8-T cells (P = .02). With regard to regulatory subset, patients displayed increased regulatory B cells (P = .05) and type-1 regulatory T cells (P = .03). With regard to CD8-T cells, a lower number of T effector memory was observed (P = .02). In contrast, among CD4-T cells, we found a higher number of T naive (P = .04) and T effector (P = .0008). Interleukin-8 (IL-8) levels and monocyte chemotactic protein-1 were increased in patients vs controls (P = .008 and P = .01, respectively). Furthermore, IL-8 levels were higher in the subgroup with neural tumor (P = .0058) (ROHHAD-NET) than in patients without neural tumor (ROHHAD). Soluble HLA-G was significantly lower in patients vs controls (P = .03).

Conclusion

Our findings contribute to support the hypothesis of immune dysregulation, which may underlie this complex, often fatal disease. Because ROHHAD(NET) syndrome is an ultra-rare disease, multicentric studies are needed to improve the effect of our data in the management of this condition.

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD): a collaborative review of the current understanding

PURPOSE

To provide an overview of the discovery, presentation, and management of Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD). To discuss a search for causative etiology spanning multiple disciplines and continents.

METHODS

The literature (1965-2022) on the diagnosis, management, pathophysiology, and potential etiology of ROHHAD was methodically reviewed. The experience of several academic centers with expertise in ROHHAD is presented, along with a detailed discussion of scientific discovery in the search for a cause.

RESULTS

ROHHAD is an ultra-rare syndrome with fewer than 200 known cases. Although variations occur, the acronym ROHHAD is intended to alert physicians to the usual sequence or unfolding of the phenotypic presentation, including the full phenotype. Nearly 60 years after its first description, more is known about the pathophysiology of ROHHAD, but the etiology remains enigmatic. The search for a genetic mutation common to patients with ROHHAD has not, to date, demonstrated a disease-defining gene. Similarly, a search for the autoimmune basis of ROHHAD has not resulted in a definitive answer. This review summarizes current knowledge and potential future directions.

CONCLUSION

ROHHAD is a poorly understood, complex, and potentially devastating disorder. The search for its cause intertwines with the search for causes of obesity and autonomic dysregulation. The care for the patient with ROHHAD necessitates collaborative international efforts to advance our knowledge and, thereby, treatment, to decrease the disease burden and eventually to stop, and/or reverse the unfolding of the phenotype.

ZSCAN1 Autoantibodies Are Associated with Pediatric Paraneoplastic ROHHAD

OBJECTIVE

Rapid-onset Obesity with Hypothalamic Dysfunction, Hypoventilation and Autonomic Dysregulation (ROHHAD), is a severe pediatric disorder of uncertain etiology resulting in hypothalamic dysfunction and frequent sudden death. Frequent co-occurrence of neuroblastic tumors have fueled suspicion of an autoimmune paraneoplastic neurological syndrome (PNS); however, specific anti-neural autoantibodies, a hallmark of PNS, have not been identified. Our objective is to determine if an autoimmune paraneoplastic etiology underlies ROHHAD.

METHODS

Immunoglobulin G (IgG) from pediatric ROHHAD patients (n = 9), non-inflammatory individuals (n = 100) and relevant pediatric controls (n = 25) was screened using a programmable phage display of the human peptidome (PhIP-Seq). Putative ROHHAD-specific autoantibodies were orthogonally validated using radioactive ligand binding and cell-based assays. Expression of autoantibody targets in ROHHAD tumor and healthy brain tissue was assessed with immunohistochemistry and mass spectrometry, respectively.

RESULTS

Autoantibodies to ZSCAN1 were detected in ROHHAD patients by PhIP-Seq and orthogonally validated in 7/9 ROHHAD patients and 0/125 controls using radioactive ligand binding and cell-based assays. Expression of ZSCAN1 in ROHHAD tumor and healthy human brain tissue was confirmed.

INTERPRETATION

Our results support the notion that tumor-associated ROHHAD syndrome is a pediatric PNS, potentially initiated by an immune response to peripheral neuroblastic tumor. ZSCAN1 autoantibodies may aid in earlier, accurate diagnosis of ROHHAD syndrome, thus providing a means toward early detection and treatment. This work warrants follow-up studies to test sensitivity and specificity of a novel diagnostic test. Last, given the absence of the ZSCAN1 gene in rodents, our study highlights the value of human-based approaches for detecting novel PNS subtypes. ANN NEUROL 2022;92:279-291.

Identification of clinical factors related to antibody-mediated immune response to the subfornical organ

OBJECTIVE

We recently reported cases of adipsic hypernatremia caused by autoantibodies against the subfornical organ in patients with hypothalamic-pituitary lesions. This study aimed to clarify the clinical features of newly identified patients with adipsic hypernatremia whose sera displayed immunoreactivity to the mouse subfornical organ.

DESIGN

Observational cohort study of patients diagnosed with adipsic hypernatremia in Japan, United States, and Europe.

METHODS

The study included 22 patients with adipsic hypernatremia but without overt structural changes in the hypothalamic-pituitary region and congenital disease. Antibody response to the mouse subfornical organ was determined using immunohistochemistry. The clinical characteristics were compared between the patients with positive and negative antibody responses.

RESULTS

Antibody response to the mouse subfornical organ was detected in the sera of 16 patients (72.7%, female/male ratio, 1:1, 12 pediatric and 4 adult patients). The prolactin levels at the time of diagnosis were significantly higher in patients with positive subfornical organ (SFO) immunoreactivity than in those with negative SFO immunoreactivity (58.9 ± 33.5 vs. 22.9 ± 13.9 ng/ml, p < .05). Hypothalamic disorders were found in 37.5% of the patients with positive SFO immunoreactivity. Moreover, six patients were diagnosed with rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation/neural tumor syndrome after the diagnosis of adipsic hypernatremia. Plasma renin activity levels were significantly higher in patients with serum immunoreactivity to the Na_x channel.

CONCLUSIONS

The patients with serum immunoreactivity to the SFO had higher prolactin levels and hypothalamic disorders compared to those without the immunoreactivity. The clinical characteristics of patients with serum immunoreactivity to the subfornical organ included higher prolactin levels and hypothalamic disorders, which were frequently associated with central hypothyroidism and the presence of retroperitoneal tumors.

Autoimmunity Related to Adipsic Hypernatremia and ROHHAD Syndrome

Specific antibody responses to subfornical organs, including Na_x antibody, have been reported in patients with adipsic hypernatremia of unknown etiology who do not have structural lesions in the hypothalamic–pituitary gland. The subfornical organ, also referred to as the window of the brain, is a sensing site that monitors sodium and osmotic pressure levels. On the other hand, ROHHAD syndrome is a rare disease for which the etiology of the hypothalamic disorder is unknown, and there have been some reports in recent years describing its association with autoimmune mechanisms. In addition, abnormal Na levels, including hypernatremia, are likely to occur in this syndrome. When comparing the clinical features of adipsic hypernatremia due to autoimmune mechanisms and ROHHAD syndrome, there are similar hypothalamic–pituitary dysfunction symptoms in addition to abnormal Na levels. Since clinical diagnoses of autoimmunological adipsic hypernatremia and ROHAD syndrome might overlap, we need to understand the essential etiology and carry out precise assessments to accurately diagnose patients and provide effective treatment. In this review, I review the literature on the autoimmune mechanism reported in recent years and describe the findings obtained so far and future directions.

Developmental disorders affecting the respiratory system: CCHS and ROHHAD

Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) and Congenital Central Hypoventilation Syndrome (CCHS) are ultra-rare distinct clinical disorders with overlapping symptoms including altered respiratory control and autonomic regulation. Although both disorders have been considered for decades to be on the same spectrum with necessity of artificial ventilation as life-support, recent acquisition of specific knowledge concerning the genetic basis of CCHS coupled with an elusive etiology for ROHHAD have definitely established that the two disorders are different. CCHS is an autosomal dominant neurocristopathy characterized by alveolar hypoventilation resulting in hypoxemia/hypercarbia and features of autonomic nervous system dysregulation (ANSD), with presentation typically in the newborn period. It is caused by paired-like homeobox 2B (PHOX2B) variants, with known genotype-phenotype correlation but pathogenic mechanism(s) are yet unknown. ROHHAD is characterized by rapid weight gain, followed by hypothalamic dysfunction, then hypoventilation followed by ANSD, in seemingly normal children ages 1.5-7 years. Postmortem neuroanatomical studies, thorough clinical characterization, pathophysiological assessment, and extensive genetic inquiry have failed to identify a cause attributable to a traditional genetic basis, somatic mosaicism, epigenetic mechanism, environmental trigger, or other. To find the key to the ROHHAD pathogenesis and to improve its clinical management, in the present chapter, we have carefully compared CCHS and ROHHAD.

ROHHAD (Rapid-onset Obesity with Hypoventilation, Hypothalamic Dysfunction, Autonomic Dysregulation) Syndrome-What Every Pediatrician Should Know About the Etiopathogenesis, Diagnosis and Treatment: A Review

Rapid-onset obesity with hypoventilation, hypothalamic dysfunction, autonomic dysregulation (ROHHAD) syndrome is a rare disease with unknown and debated etiology, characterized by precipitous obesity in young children, hypoventilation and autonomic dysregulation with various endocrine abnormalities. Neuroendocrine tumors can be associated in more than half of the cases. This rare condition has a severe outcome because of high morbidity and mortality. We provide a comprehensive description of the etiopathogenetic theories of the disease, clinical presentation, diagnostic workup and treatment possibilities.