Familial Glucocorticoid Deficiency Presenting with Tonic-Clonic Seizure: A Case Report

HIGHLIGHTS: Familial glucocorticoid deficiency is a rare disease with nonspecific clinical presentations that can lead to late diagnosis with high rates of morbidity and mortality. In a child with features of low serum cortisol and high ACTH, namely, hypoglycemia and hyperpigmentation, FGD should have a place in the differential diagnosis list. ABSTRACT: Introduction: Familial glucocorticoid deficiency (FGD) is a rare cause of adrenal insufficiency in children. The condition can present with features of low cortisol and high adrenocorticotropic hormone (ACTH). Late diagnosis can be associated with high morbidity and high mortality rates. Patient: The presented case was a three-year-old Saudi girl who presented with dehydration and seizures as a complication of hypoglycemia. The initial examination and investigations revealed hyperpigmentation and normal arterial blood pressure. The lab investigation and genetic study revealed hypoglycemia, metabolic acidosis, low serum cortisol: 53 nmol/L (N: 140–690 nmol/L), normal androgens: 0.65 nmol/L (N: 0.5–2.4 nmol/L) and aldosterone: 50 pgmL (N: 2–200 pg/mol), and normal serum electrolytes. The ACTH level was more than 2000 pg/mL. A genetic study indicated a homozygous likely variant in the nicotinamide nucleotide transhydrogenase (NNT) gene, consistent with a genetic diagnosis of autosomal recessive glucocorticoid deficiency type 4. No mutations were found regarding MC2R, MRAP, and TXNRD2. Intervention and outcome: The child was started on hydrocortisone, initially at 100 mg/m(2)/dose IV and then 100 mg/m(2)/day divided to q 6 hr. The dose was gradually decreased to 15 mg/m(2)/day PO BID, with clinical improvement and normalization of the serum ACTH level. Conclusions: The autosomal recessive glucocorticoid deficiency, a variant of FGD type 4, is a very rare condition that may lead to high rates of mortality when the diagnosis and treatment occur late. Therefore, early diagnosis and treatment is essential for good outcomes.