Endocrine Abstracts

Background: Sex chromosome mosaicism is a recognized cause of disorders of sex development (DSD); Mixed gonadal dysgenesis (MGD) most often associated with 45, X/46 XY with broad phenotypes from m ambiguous genitalia to typical male or female appearance. Management is complex and multidisciplinary (sex assignment, surgical planning, fertility and tumor surveillance) Three lines mosaicism are uncommonly reported their phenotypic expression is unknown.

Method, Observation: Non consanguineous parents presented their child of pediatric endocrinology at 15 months of age for evaluation of ambiguous genitalia, raised as a girl with legal sex still undeclared. Examination revealed a phallic structure of 1.5 cm with a single mid-ventral urethral opening, asymmetrical rugose labioscrotal folds resembling a hypoplastic scrotum, a palpable right gonad, and no palpable left gonad including along the inguinal canal. Growth parameters were normal, and no dysmorphic features were observed. Born at term, with no particular familiar history. Hormonal evaluation at 2 days of life showed testosterone 7.56 nmol/l, low AMH 13.18 ng/mL, DHT 0.41 nmol/l, FSH 1.05 IU/L, LH 0.09 IU/L, and 17-hydroxyprogesterone 10 ng/mL, suggestive of detectable Leydig cell function with Sertoli dysfunction. At 1month urogenito-cystograhy and ultrasounds( US)revealed left lateralized uterus, vagina communicating with a male type curved urethra and a right testis within the scrotal bursa. Constitutional Karyotyping at 10 months demonstrated a rare three-line mosaicism: 46, XY (60%), 47, XYY (20%), 45, X (20%).

Results/Outcome: All finding consistent of gonadal dysgenesis. Parents were counseled regarding fertility, surgical reconstruction, and hormonal therapy. Initially,they intended to raise the child as a girl. However, following evaluation by a national multidisciplinary DSD board, male sex assignment was recommended and was subsequently accepted. Two Testosterone injections resulted in phallic growth and right testicular development. Ultrasound at 21 months suggested a hypoechogenic structure in the left inguinal hernia, likely a hypotrophic left gonad. AMH levels normalized, indicating improved Sertoli cell function.

To conclude : The child is now 3 years old, awaiting surgical staff/intervention, highlighting the prolonged diagnostic, legal, and therapeutic pathway in complex DSD