CASE:
X is a 22-month-old White male infant with a complex medical history, including diagnoses of FBXO11 mutation, hypotonia, restrictive lung disease and mild intermittent asthma, laryngotracheomalacia, obstructive sleep apnea (OSA), feeding difficulties with a history of aspiration, gastroesophageal reflux disease (GERD), and developmental delays. X's medical presentation has resulted in multiple prior medical admissions for respiratory failure due to acute illnesses, procedures and treatments including gastrojejunostomy (GJ) tube dependence, supraglottoplasty to reshape tissues of the upper larynx, and the use of biphasic positive airway pressure (BiPAP) at night and room air during the day when he is at baseline. In addition, he has nocturnal events characterized by significant agitation, screaming, crying, body stiffening and limb movements with pauses in breathing, mouth breathing, restless sleep, and difficulty waking in the morning with concomitant daytime fatigue despite above treatments for OSA. There is no history of congenital heart disease or sudden unexplained death. Family history is noncontributory because parents are negative for the FBXO11 variant.
X's sleep disruption has led to significant sleep deficits for both X and his caregivers, who spend much of the night strategizing on how to console him. X has undergone several sleep studies, starting when X was aged 4 months, at several children's hospitals across the nation to determine the cause of his chronic sleep disturbance, which yielded limited information and treatment success. As an infant, X received a medical workup and was subsequently treated with a proton pump inhibitor (PPI) for reflux. At 12 months, he was diagnosed with disordered sleep with myoclonic jerks and started on melatonin and gabapentin for involuntary movements. At 13 months, gabapentin was weaned back because of intolerance, and at 15 months, nortriptyline and clonidine were started because of worsening symptoms to target potential neuropathic pain. While most of his symptoms were at night, he had occasional daytime screaming episodes, particularly when experiencing illness. Gabapentin and clonidine were stopped because nortriptyline seemed most effective.
At 17 months, the results from a sleep study led to a diagnosis of night terrors, and several clinicians agreed that X's sleep disruption was behavioral in nature. At this time, an infant mental health consultant met with a sleep psychologist on the family's behalf to support family in considering systematic desensitization therapy to increase tolerance to wearing his BiPAP mask, as well as other behavioral and sleep hygiene strategies, which were tried on several occasions and again, resulted in limited improvement in functioning.
At 19 months, X's multidisciplinary team reconsidered a night terror diagnosis after a failed trial of clonazepam and pursued a differential diagnosis of periodic limb movement disorder (PLMD). X trialed gabapentin again, but this time only a nighttime dose, per sleep medicine and psychiatry recommendation. While this brought some temporary relief from nighttime distress, despite increasing to the highest dose for age and weight (15 mg/kg/dose), this became less effective, and he was weaned off at 22 months. He had been on iron supplementation since age 6 months and received an iron infusion at 22 months because of persistently low ferritin levels and PLMD in sleep.
At 24 months, X was briefly trialed on levetiracetam. While no evidence for seizures on EEG was present, this medication was chosen for involuntary movements and genetic risk for seizures. However, this medication was not useful. At 25 months, an evaluation with a movement disorder physiatrist resulted in a diagnosis of nocturnal paroxysmal dystonia, and he was started on baclofen, which has provided some, but not complete relief to nighttime symptoms. Parents are reporting he has more “good nights” than “bad nights,” but “bad nights” come in stretches of a few days in length with no known trigger or relief.
Most recently, X was evaluated by general genetics. Whole exome sequencing (WES) was pursued which revealed a pathogenic de novo variant in FBXO11 and provides a likely cause for his neurodevelopmental phenotype. However, he has some features not explained by FBX011; thus, reanalysis of his WES was performed and revealed a de novo variant of uncertain significance in RAF1. Because pathogenic variants in RAF1 have been associated with dilated cardiomyopathy and Noonan spectrum disorder, it was recommended that X be followed periodically in a cardiac genetics clinic. Family is well connected into the FBXO11 community, including supportive Facebook groups. Parents have shared that they do not feel X's breathing issues and pain fit with the phenotype of other children with FBXO11 mutations.
X is also enrolled in a medical child care program to facilitate development and social-emotional functioning and receives learning, speech, occupational, physical, and feeding therapy while in attendance. Despite periods of absence due to contracting numerous viral illnesses over the past several months, X continues to make progress across developmental therapies and happily engages when at the program.
What additional diagnostic tests and treatment should be considered to better understand X's medical and behavioral presentation? What are the implications of chronic sleep deprivation and stress on the behavior and development of infant with X's profile? What are important psychosocial considerations because it relates to children with medical complexity (CMC), particularly for X and his family to support caregiver, family, and X's quality of life and overall well-being?
