Evaluation and treatment of autoimmune neurologic disorders in the pediatric intensive care unit

ROHHAD syndrome without rapid-onset obesity: A diagnosis challenge

BACKGROUND

ROHHAD syndrome (Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation) is rare. Rapid-onset morbid obesity is usually the first recognizable sign of this syndrome, however a subset of patients develop ROHHAD syndrome without obesity. The prevalence of this entity is currently unknown. Alteration of respiratory control as well as dysautonomic disorders often have a fatal outcome, thus early recognition of this syndrome is essential.

MATERIAL AND METHODS

A retrospective, observational, multicenter study including all cases of ROHHAD without rapid-onset obesity diagnosed in France from 2000 to 2020.

RESULTS

Four patients were identified. Median age at diagnosis was 8 years 10 months. Median body mass index was 17.4 kg/m². Signs of autonomic dysfunction presented first, followed by hypothalamic disorders. All four patients had sleep apnea syndrome. Hypoventilation led to the diagnosis. Three of the four children received ventilatory support, all four received hormone replacement therapy, and two received psychotropic treatment. One child in our cohort died at 2 years 10 months old. For the three surviving patients, median duration of follow-up was 7.4 years.

CONCLUSION

ROHHAD syndrome without rapid-onset obesity is a particular entity, appearing later than ROHHAD with obesity. This entity should be considered in the presence of dysautonomia disorders without brain damage. Likewise, the occurrence of a hypothalamic syndrome with no identified etiology requires a sleep study to search for apnea and hypoventilation. The identification of ROHHAD syndrome without rapid-onset obesity is a clinical challenge, with major implications for patient prognosis.

NUDT15 R139C variation increases the risk of azathioprine-induced toxicity in Chinese subjects: Case report and literature review

INTRODUCTION

Azathioprine (AZA) is widely used as an immunosuppressive agent, and its efficacy has been recommended by many clinical studies. However, leukopenia, the most common toxicity, still restricts its clinical applications. Recent studies found that NUDT15 R139C polymorphism is strongly associated with AZA-induced leukopenia in Koreans. However, the follow-up studies available are all limited to inflammatory bowel disease (IBD). Here, we report a case of a Chinese patient with Sjögren syndrome (SS) with wild-type TPMT*3C who was diagnosed with AZA-induced severe toxicity due to NUDT15 mutation based on clinical and laboratory characteristics.

CASE PRESENTATION

A 22-year-old Chinese woman with SS developed severe leukopenia after AZA administration for 21 days. Detection of 6-thioguanine nucleotides (6-TGN) showed that the erythrocyte concentration had beyond the monitoring range, indicating that severe leukopenia might be caused by AZA. Furthermore, gene sequencing showed that NUDT15 R139C (poor metabolizer) homozygosity might explain this adverse event. Based on the evidence, AZA administration was immediately stopped and supportive treatments provided, and the patient eventually recovered.

CONCLUSION

In this report, we first provide detailed clinical and laboratory characteristics of AZA-induced leukopenia in a patient with SS with a mutant NUDT15 R139C genotype (TT allele) and normal TPMT activity. This case indicates that NUDT15 R139C and TPMT*3C genotypes, and more importantly, 6-TGN levels, should be routinely monitored for those administered with AZA to predict and prevent AZA-induced toxicity.