A male infant born at 38 weeks gestation faced life-threatening respiratory failure shortly after birth, revealing a rare case of Congenital Central Hypoventilation Syndrome (CCHS).
While initial assessments at the birth hospital suggested potential pulmonary issues, the infant’s persistent, sleep-predominant apnea led to a transfer to a tertiary neonatal intensive care unit at 11 days of age, Cureus reported.
Medical teams excluded common metabolic, infectious, and structural causes of breathing difficulties before turning to genetic testing. Whole-exome sequencing confirmed a heterozygous PHOX2B polyalanine repeat expansion mutation, specifically a 20/31 genotype. This genetic variant, which affects the PHOX2B transcription factor, causes the brain to lose its automatic control over breathing, particularly during sleep.
Escalating Care Through Intubation, Tracheostomy and Infection Treatment
The infant’s condition required an escalation of care that moved beyond non-invasive support. By day of life 14, clinicians intubated the patient to manage worsening hypercapnia, a state where carbon dioxide levels build up because the body fails to trigger a sufficient breathing response.
To enable long-term mechanical ventilation, surgeons performed a tracheostomy at seven weeks of age. The infant also faced a secondary complication involving respiratory colonization and infection by AmpC-producing Enterobacter cloacae. Treatment with carbapenem therapy successfully normalized inflammatory markers, though the patient remained colonized with the bacteria.
Genetic Counseling Addresses De Novo Mutation and Recurrence Risks
The diagnostic process included comprehensive genetic counseling to address the parents’ concerns regarding future pregnancies. Testing confirmed the PHOX2B mutation was de novo, meaning it was not inherited from either parent.
However, the medical team cautioned that a "low but non-zero" recurrence risk remains for future siblings. This risk arises from the possibility of parental germline mosaicism, a condition where a small proportion of reproductive cells carry the mutation even if the parents’ blood tests appear normal. The patient himself faces a 50% risk of passing the variant to his own children in the future.
Transitioning to Home-Based Ventilation and Continuous Monitoring
The infant currently remains in the neonatal intensive care unit, where he is clinically stable on mechanical ventilation. The multidisciplinary team is coordinating a transition plan that focuses on home-based ventilatory support.
Care requires constant vigilance, as patients with CCHS do not display traditional signs of respiratory distress like gasping or increased work of breathing. The long-term plan involves continuous, 24-hour monitoring to prevent life-threatening respiratory decompensation.
Why CCHS Resembles Lung Disease and the Significance of the 20/31 Genotype
Why is CCHS often mistaken for lung disease?
CCHS patients often appear well while awake but suffer from shallow breathing or apnea during sleep. Because these symptoms resemble respiratory distress, clinicians often investigate primary lung or airway issues first before realizing the failure is in the brain’s autonomic control of breathing.
What is the significance of the 20/31 genotype?
The PHOX2B gene contains a stretch of alanine amino acids; in CCHS, this stretch is expanded. While a normal gene has 20 repeats, genotypes like 20/31 are associated with more severe phenotypes, including a higher likelihood of continuous ventilatory dependence and autonomic nervous system complications.
Is there a cure for this syndrome?
There is currently no cure for CCHS, and most affected individuals require lifelong ventilatory support. Management focuses on providing mechanical breathing assistance and closely monitoring for associated autonomic issues, such as heart rhythm irregularities or bowel problems.