Cholestasis and Hepatic Iron Deposition in an Infant With Complex Glycerol Kinase Deficiency

We present a 6-week-old male infant with persistent hyperbilirubinemia, hypertriglyceridemia, elevated creatine kinase levels, and transaminitis since the second week of life. When he developed hyperkalemia, clinical suspicion was raised for adrenal insufficiency despite hemodynamic stability. A full endocrine workup revealed nearly absent adrenocorticotropic hormone. Coupled with his persistent hypertriglyceridemia (peak of 811 mg/dL) and elevated creatine kinase levels (>20 000 U/L), his corticotropin level lead to a clinical diagnosis of complex glycerol kinase deficiency (GKD), also known as Xp21 deletion syndrome. This complex disorder encompasses the phenotype of Duchenne muscular dystrophy, GKD, and congenital adrenal hypoplasia due to the deletion of 3 contiguous genetic loci on the X chromosome. Our case exemplifies the presentation of this disorder and highlights the important lesson of distinguishing between adrenal hypoplasia congenita and congenital adrenal hyperplasia, as well as the sometimes subtle presentation of adrenal insufficiency. To our knowledge, it is also the first reported case of complex GKD deficiency with the additional finding of hepatic iron deposition, which may indicate a potential area for exploration regarding the pathogenesis of liver injury and cholestasis seen in cortisol-related endocrinopathies.