Congenital adrenal hypoplasia with neurodevelopmental delay due to contiguous Xp21 deletion: a case series with review of literature

X-linked adrenal hypoplasia congenita (AHC) is a rare, life-threatening disorder caused by pathogenic variants in NR0B1 (DAX1), leading to adrenal insufficiency and hypogonadotropic hypogonadism. AHC is often associated with Xp21 contiguous gene deletion syndrome, which involves the deletion of multiple genes, including NR0B1, GK, DMD, and IL1RAPL1, resulting in a spectrum of phenotypic manifestations, such as glycerol kinase deficiency (GKD), Duchenne muscular dystrophy (DMD), and neurodevelopmental disorders. We report two cases of AHC with neurodevelopmental delays due to contiguous Xp21 deletions involving NR0B1 and IL1RAPL1, each diagnosed through distinct clinical pathways. Case 1 involved a neonate with adrenal insufficiency, persistent hyperCKemia, and excessive urinary glycerol excretion, leading to a diagnosis of Xp21 deletion syndrome with DMD and GKD. The patient's sister, an asymptomatic carrier, exhibited elevated CK levels and mild developmental delays. Array comparative genomic hybridization identified a novel complex structural variation, including duplication-deletion-duplication rearrangement, which may have modified clinical manifestations. Case 2 involved a 10-year-old boy with AHC and developmental delay that was initially considered a consequence of adrenal crises. Genetic analysis confirmed an Xp21 deletion, including IL1RAPL1, implicating it in his intellectual disability. A literature review reveals that Xp21 deletions involving IL1RAPL1 are strongly associated with neurodevelopmental delays, suggesting a distinct phenotype within Xp21 deletion syndromes. Early genetic diagnosis via chromosomal microarray analysis facilitates precise delineation of deletion regions, aiding in clinical management, genetic counseling, and early intervention strategies. Further studies are needed to elucidate genotype-phenotype correlations in Xp21 deletion syndromes and optimize individualized medical care.