Abstract
Background: Steroidogenic Acute Regulatory (StAR) deficiency is a rare form of congenital adrenal hyperplasia characterized by dysregulated cholesterol transport mediated by StAR enzyme across mitochondrial membranes. Adrenal dysfunction is due to the two-hit hypothesis: 1) defective StAR protein and 2) cholesterol accumulation in the adrenals and gonads. With variable cellular damage, adrenal crisis can occur early or late. Clinical cases: We present two cases of StAR deficiency with contrasting presentations. Case 1: A 9-day old ex full term female from a nonconsanguineous union presented to a rural hospital with hypothermia, lethargy, and poor feeding. She had hypoglycemia 41 mg/dL (60–105), hyponatremia 120 mEq/L (135–145), hyperkalemia 7.7 mEq/L (3.5–5.5) and cortisol < 0.4 ug/dL (4.5–23). Baby was started on hydrocortisone (HCT) 100 mg/m2 and one-time fludrocortisone (FCT). She decompensated requiring chest compressions, intubation and pressors. She was transferred to our institution. Newborn screen was normal; she had typical female external genitalia. US demonstrated a uterus; ovaries and adrenals were not identified. Upon extubation and clinical improvement, her HCT was weaned to physiologic doses. She became hyponatremic requiring FCT and salt supplements. Post-HCT wean, ACTH level was 304 pg/mL (7–63) with aldosterone < 4.0 ng/dL (6.5–86). Karyotype was 46,XX. Genetic analysis revealed a novel heterozygous likely pathogenic variant in the STAR gene, (STAR c.65-12_68del variant) without defect in the other STAR gene. Case 2: A 9-month-old ex full-term female of Iraqi descent from a nonconsanguineous union presented with fatigue, poor oral intake and weight loss from 50%-ile to 3%-ile. She had hyponatremia 122 mEq/L, hyperkalemia 8.0 mEq/L, but was normoglycemic. She was normotensive; EKG was normal. Parents noted progressive hyperpigmentation including her gums, palmar and plantar creases. She had typical external female genitalia with a hypoplastic clitoris (2 mm x 2 mm). ACTH stimulation test showed low cortisol (0.5 ug/dL) at 60 minutes. She was treated with HCT 100 mg/m2 for 5 days, then tapered to maintenance dosing, with FCT and salt supplements. Her ACTH level returned > 5000 pg/ml. Aldosterone, 17-OH-Progesterone, 17-OH-Pregnenolone, 11-Deoxycortisol and androstenedione were undetectable. Pelvic US did not identify uterus or ovaries. Pelvic MRI identified bilateral inguinal testes with enlarged adrenal glands. Karyotype was 46, XY. We suspected StAR deficiency with sex-reversal. Genetic analysis revealed a known homozygous mutation in STAR (c.545G>A). Conclusion: StAR deficiency is clinically indistinguishable from P450scc deficiency and genetic testing is needed. Both entities can present with early or delayed adrenal crisis. While classic for StAR deficiency, adrenal enlargement is inconsistent. Karyotype is vital to identify sex reversal.
Genetic analysis does not confirm non-classical congenital adrenal hyperplasia in more than a third of the women followed with this diagnosis
