Development in a 46 XX Boy with Positive SRY Gene

Abstract

We present the case of an 11 year-old boy, who asked for medical attention due to obesity and assumed underdeveloped external genitalia. He did not have genital anomalies, penile length was 5.3 cm, testicular volume 2 ml and pubic hair Tanner stage 1. His bone age was normal for chronological age. Endocrinological study showed normal results for his age. Karyotype revealed a 46 XX pattern. MRI of external genitalia showed bilateral scrotal testes which were normal in diameter for his age. The check of his historical growth chart and follow-up revealed normal growth with spontaneous pubertal development. However, hormonal studies showed progressive increase of FSH levels, indicative of failure of germinal epithelium. The presence of Y sequences, including SRY gene, was demonstrated by PCR. Our observation is in agreement with the view that 46 XX male subjects diagnosed at peripubertal age with the SRY gene in the genome have a good prognosis regarding growth and development, but the principal problem of these patients is infertility.

SRY gene transferred to the long arm of the X chromosome in a Y-positive XX true hermaphrodite

“…Numerous XX males have been characterized by the presence of a Yp fragment transferred to Xp22 [Andersson et al, 1986;Magenis et al, 1987;Margarit et al, 1998]. This Y fragment includes the testicular determinant gene SRY, giving maleness to XX individuals [Rego et al, 1996]. Interestingly, the same Xp/ Yp translocation has been found in 3 XX true hermaph-rodite patients [Berkovitz et al, 1992;McElreavey et al, 1992].…”

An Sry-Positive 46,XX Male

“…The FSH and LH levels were high and he had low levels of both total and free testosterone, accompanied by normal but small testes. A 46,XX boy with an SRY gene, without genital anomalies and progres sive increase in FSH levels, indicating failure of germinal epithelium has been reported [7]. In five infertile XX males, the FSH levels were elevated in three and LH level raised in two cases, whereas the testosterone levels were low in three cases [8]; they showed different variants in their phenotypes, such as small penises, hypospadias, cryptorchidism, flat scrotums and in some, small testes.…”

46,XX, der(15),t(Y;15)(q12;p11) karyotype in an azoospermic male

“…[2526] Translocations belonging to the first group, most commonly t(Y;15), have been seen in normal individuals and are therefore thought to be compatible with a normal phenotype including fertility. [2728] Translocations of the second type often lead to an abnormal phenotype, notably including sterility. [29]…”