PLOD1 and Klinefelter syndrome: Although SRY-positive individuals rarely present with genital abnormalities, they often show the phenotypic features of Klinefelter syndrome, such as hypogonadism, gynecomastia, azoospermia, and hyalinization of the seminiferous tubules, all of which are associated with altered hormone levels during puberty (low testosterone, elevated follicle-stimulating hormone (FSH), and luteinizing hormone [LH]) [66].