Objective: To analyze the clinical and genetic characteristics of a patient with congenital isolated adrenocorticotropic hormone deficiency (IAD).
Methods: Clinical characteristics of the patient was reviewed. Genomic DNA of the child was subjected to whole exome sequencing.
Results: Genetic testing has confirmed the diagnosis of congenital IAD by identification of compound heterozygous variants of the TBX19 gene, which included a pathogenic nonsense c.535C>T (p.R179X) variant inherited from his father and a novel missense c.298C>T (p.R100C) variant inherited from his mother.
Conclusion: Congenital IAD due to variants of the TBX19 gene is a rare autosomal recessive disease. It is characterized by low plasma adrenocorticotropic hormone and cortisol levels but normal levels of other pituitary hormones. Delayed diagnosis may lead to severe early-onset adrenal failure and wrong treatment which may result in neonatal mortality. Hydrocortisone replacement is effective. Detection of pathogenic variant of TBX19 gene is the key to diagnosis.