To describe clinical, laboratory, and radiologic findings in kernicterus due to glucose-6-phosphate dehydrogenase (G6PD) deficiency, with emphasis on early recognition and treatment.

G6PD deficiency is an X-linked disorder affecting 1 in 10 African American males and can result in severe hyperbilirubinemia and chronic bilirubin encephalopathy, or kernicterus. Symptoms of kernicterus include hypotonia, apneic episodes, hearing impairment, motor dysfunction, and seizures. MRI characteristically shows abnormal signal in the basal ganglia, correlating with bilirubin deposition in these structures. Surviving patients may have long-term neurologic deficits. 

A 7-day old African American boy born at full term presented for evaluation of jaundice, hypotonia, and poor feeding. Initial evaluation showed indirect bilirubin of 29.4 mg/dl. The patient was admitted for phototherapy to treat presumed breast milk jaundice. Overnight, he developed apneic episodes requiring noninvasive positive-pressure ventilation and was noted to have rhythmic twitching of the right side of the mouth.

Exam showed diffuse hyperreflexia, hypotonia, and an incomplete Moro reflex without adduction or anterior flexion. EEG showed several multifocal seizures and sharp waves indicative of a widespread encephalopathic process. MRI brain demonstrated abnormal increased T1 signal bilaterally in the globus pallidus. His G6PD level returned at 2.4 U/g Hb (normal 9.9-16.6 U/g Hb).

He was initiated on phenobarbital for his seizures with excellent response. Bilirubin levels normalized on day 3 of admission with phototherapy. He was evaluated in the clinic 2 weeks following discharge, with continued seizure freedom, improved tone, and no abnormal movements. Genetic testing eventually revealed a pathogenic “A-“ allele consistent with a diagnosis of G6PD deficiency.

Kernicterus is a preventable cause of neurologic disability. G6PD deficiency remains an important cause of kernicterus in developed countries. ºÃÉ«ÏÈÉú of healthcare workers and parents in the recognition of neonatal jaundice in high-risk infants is critical to early treatment and prevention of long-term neurologic complications.