SAT-428 Successful Treatment Of Congenital Adrenal Hyperplasia 11 Beta Hydroxylase Deficiency With Crenessity

Abstract Disclosure: C. Jedel: None. E. Volcotrub: None. A. Khattab: None. S.B. Ten: None. Successful treatment of Congenital Adrenal Hyperplasia 11 Beta Hydroxylase Deficiency with Crenessity.Case report.Introduction.The FDA approved Crinecerfont (Crenessity) on December 13, 2024, to treat classic congenital adrenal hyperplasia (CAH). Crenessity selectively blocks CRF binding to CRF1 receptors in the pituitary gland, directly reducing ACTH and the downstream production of androgens. The current standard of treatment is daily supraphysiologic doses of glucocorticoids, which leads to numerous complications. Crenessity reduces excessive adrenal androgen production, which can help decrease the amount of glucocorticoid medication needed and improve adrenal function.Case report.We report the first case of a combination of Crenessity and Cortef therapy in a 8 11/12-year-old boy with CAH, 11 Beta Hydroxylase Deficiency.He was born after a normal pregnancy, FT, with a BW of 8 lbs. His mother noticed pubic hair at 6 years of age. On examination, the testes were Tanner I, prepubertal, and pubic hair Tanner II. His BP and electrolytes were normal.He was growing more at 99 % while his target height was at 50 % (70”). Bone age (BA) was advanced to 11 6/12 yrs at Chronological age (CA) 6.4 yrs. BA was 13.6 to 14 yrs at CA 8 11/12 yrs.At 6.4 yrs., his 17 OHP 320 ng/dl ( Nl < 137 mg/dl), DHEA 620 ( Nl < 487 ng/dl), DHEAS 209 ( Nl < 22 mcg/dl), and testosterone 81 ng/dl ( Nl < 25 ng/dl), ACTH 120 (Nl 9-57 pg/ml) were elevated, cortisol 17 ( Nl 3-25 mcg/dl) and 21CYP21A2 gene analysis were normal. LH, FSH were prepubertal. 11-Deoxycortisol 9981 (Nl < 195 ng/dl ) and Deoxycorticosterone (DOC) 1123 ( Nl < 44 ng/dl) were elevated. Genetic analysis revealed CYP11 B1 Deletion (Exons 1-6), heterozygous pathogenic, and CYP11 B1 c.1268A>G (p.Tyr423Cys), heterozygous novel mutation.Before Crenessity was started at 8 11/12 yrs, on Cortef 10.2 mg/m2: Deoxycorticosterone was 161 ng/dl, 11-Deoxycortisol was 749 ng/dl, testosterone 10 ng/dl.Six weeks later after Crenessity was started at 50 mg twice a day, the steroid profile became normal for the first time in the last 3 years: Deoxycorticosterone 20 ng/dl, 11-Deoxycortisol 150 ng/dl, Androstenedione 17 ng/dl, testosterone 2 ng/dl, and ACTH 16 pg/ml.Dose was decreased to 8.2 mg/m2 and Crenessity was continued at the same dose, 50 mg twice a day.Six weeks later, testosterone increased to 6 ng/dl within the normal range, Deoxycorticosterone increased to 324 ng/dl ( NL < 44), and ACTH increased to 35 pg/ml (NL 9-57 pg/ml). He complained of an episode of fatigue. I advised to increase the dose of Cortef to 10.2 mg/m2 and continue Crenessity 50 mg twice a day. Conclusion: The combination of Crenessity and Cortef normalized the steroid profile for the first time in 3 years of treatment in the case of CAH 11 beta-hydroxylase deficiency. There were no complications, and the child tolerated therapy well. Presentation: Saturday, July 12, 2025