This study comprised 23 patients with DSD who presented with asymmetric gonads at the Department of Pediatrics at Asan Medical Center Children's Hospital in Seoul, Korea. The presenting features, endocrinological findings, karyotypes, presence of Müllerian duct remnants, pathological findings of the gonads, sex of rearing, and pubertal outcomes were reviewed retrospectively.

Patients with sex chromosome DSD whose diagnoses were not confirmed pathologically were excluded from this study. Sex assignment was based on integrative assessments of the external genitalia, presence of a uterus, functioning testicular tissues, hormonal profiles, and karyotypes and was performed using a multidisciplinary approach with informed consent from the parents of each patient.

External genitalia were rated using the external masculinization score (EMS) [12]. A micropenis was defined as a stretched penile length less than 2.5 cm in a full-term neonate [13]. Internal genital organs were assessed by ultrasonography or magnetic resonance imaging.

A human chorionic gonadotropin (hCG) stimulation test was performed in 10 patients to evaluate Leydig cell function. Serum testosterone level was measured at baseline and on the fourth day after consecutive intramuscular hCG injections at a dose of 1,000 units/day for 3 days. The testosterone response to hCG was regarded as positive if the level increased to at least twice baseline or above the upper limit of the prepubertal testosterone level [14].

Chromosomal analysis was performed in all subjects by examining metaphase G bands prepared from peripheral blood lymphocytes using conventional techniques [15]. Histopathological diagnosis of the gonads to differentiate ovotesticular DSD from MGD was based on resected or biopsied tissues.

Gonadectomy or biopsy was performed at a median age of 2.9 years (range, 1 month–15.1 years). Subsequently, 14 patients were diagnosed with ovotesticular DSD, and 9 were diagnosed with MGD. The positions and histology of the gonads are summarized in Tables 1 and 2.

In the 14 patients with ovotesticular DSD, the most common karyotype was 46,XX (10 of 14, 71.4%), followed by 45,X/46,XY (3 of 14, 21.4%) and 46,XX/46,XY(1 of 14, 7.1%). A gonadal combination of testis and ovary was the most common finding (10 of 14, 71.4%), followed by bilateral ovotestes (2 of 14, 14.3%), ovary and ovotestis (1 of 14, 7.1%), and testis and ovotestis (1 of 14, 7.1%).

In the 9 patients diagnosed with MGD, the most common karyotype was 45,X/46,XY (6/9, 66.7%). Other mosaicisms were identified in the other 3 patients (33.3%): 45,X/46,X,del(Y) (q11.23), 45,X/46,X,add(Y)(p.11.3), and 45,X/47,XY,+del(Y) (q12).

All 23 patients presented with ambiguous genitalia, such as a micropenis, cryptorchidism, hypospadias, or clitoromegaly, at a median age of 1 month (range, 1 day–1.6 years). Eleven of 14 patients with ovotesticular DSD (78.6%) and all 9 patients with MGD (100%) presented with asymmetric gonads. The appearance of the genitalia included prominent labia majora or absent scrotal rugae (13 of 23, 56.5%), hypospadias (15 of 23, 65.2%), clitoromegaly (8 of 23, 34.8%), cryptorchidism (5 of 23, 21.7%), and micropenis (4 of 23, 17.4%). The EMSs ranged between 2.5 and 11.5. None of the patients exhibited the stigmata of Turner syndrome. Müllerian duct remnants were identified in 10 of 14 patients with ovotesticular DSD (71.4%) and in 5 of 9 patients with MGD (55.6%).

Level of 17α-hydroxyprogesterone was measured in 16 subjects and was normal in all, excluding the possibility of congenital adrenal hyperplasia. The hCG stimulation test was performed in 8 subjects with ovotesticular DSD and in 2 subjects with MGD during the prepubertal period (range, 4–11 months). Seven of the 8 subjects (87.5%) with ovotesticular DSD and both subjects (100%) with MGD showed a positive response.

Eight of the 14 patients (57.1%) with ovotesticular DSD were assigned as male, and 7 of these patients (50%) had preserved testis. The remaining 6 patients (42.9%) were raised as female, and the ovaries were preserved in 3 of these 6 patients (50%). Among the 8 male-assigned patients, unilateral gonadectomy was performed in 7 at a median age of 1.5 years (range, 4 months–15.1 years). In these 7 patients, the ovotestis or ovary was removed, whereas the testis was preserved to induce spontaneous puberty. Subject 3, a male-assigned patient with bilateral ovotestes in the scrotum, underwent bilateral gonadectomy at age 15.1 years due to spontaneous rupture of the left gonad. Of 6 female-assigned patients, 3 underwent bilateral or unilateral gonadectomy at a median age of 12 months (range, 1 month–9.2 years). Eight patients with ovotesticular DSD (5 males and 3 females) reached pubertal age during the study period, which was defined as ≥12 years for males and ≥10 years for females. Of these 8 patients, 6 with ovotesticular DSD (4 males and 2 females) showed spontaneous puberty (Table 3). The hCG stimulation test was performed in 3 of 4 male-assigned patients with spontaneous puberty, and all 3 patients were responsive. One female- and 3 male-assigned patients underwent unilateral gonadectomy at a median age of 2.4 years (range, 9 months–14 years). Subject 7, who underwent clitoroplasty at another hospital, was referred to our institute at the age of 9.1 years with clitoromegaly. The patient’s Tanner stage was breast II and pubic hair II with serum luteinizing hormone and follicle-stimulating hormone levels of 6.0 and 5.0 mIU/mL, respectively (Table 3). As the patient was reared as a female, bilateral gonadectomy was performed at 9.2 years of age. Three patients (subjects 3, 6, and 13) were treated with sex hormone replacement therapy. One male-assigned patient (subject 3) underwent bilateral gonadectomy due to spontaneous rupture of gonads at age 15.1 years; the patient was subsequently treated with testosterone enanthate. One female-assigned patient (subject 13) who underwent bilateral gonadectomy at the age of 1.3 years showed hypergonadotropic hypogonadism. This patient was treated with estrogen/progesterone replacement therapy starting at the age of 11.4 years. One male-assigned patient with ovotesticular DSD (subject 6) had sex identity problems and sex dysphoria at age 20 years. The patient changed his sex to female and subsequently underwent treatment with estrogen replacement therapy (Table 3, Fig. 1).

Seven of the 9 patients with MGD (77.8%) were raised as males, whereas the remaining 2 patients were raised as females. Six of the male-assigned patients underwent a unilateral gonadectomy. The 2 female-assigned patients underwent a bilateral (n=1) or unilateral (n=1) gonadectomy to avoid virilization. Two patients with MGD reached pubertal age. Of these, puberty occurred spontaneously in one phenotypic male at the age of 11.8 years (subject 19) with MGD, and sex hormone replacement was not necessary during the follow-up period (Table 3, Fig. 1). The remaining one female with MGD (subject 15) who underwent a right gonadectomy at the age of 1.2 years showed hypergonadotropic hypogonadism caused by a contralateral dysgenetic gonad and was treated with estrogen replacement therapy starting at 11.5 years of age.