Sexual Development, Puberty and Adolescence MCQs

Explanation: The SRY gene/region is the sex-determining gene/region located on the distal region of the short arm of the Y chromosome . It has a significant role in determining male sex and expresses at the 5th to 6th week of development. In XX karyotype the absence of this gene expression leads to ovarian development. Mutation of the SRY gene leads to Swyer syndrome. Patients with Swyer syndrome have a 46XY karyotype , but their Mullerian system develops normally. These individuals are phenotypically female with both female external and internal genitalia. Their gonads are usually streak ovaries composed only of gonadal stroma, while the vagina, uterus, and fallopian tubes are all formed. Reference: https://pubmed.ncbi.nlm.nih.gov/8840551/#:~:text=Abstract,testis%20from%20an%20undifferentiated%20gonad.

Explanation: In gonadal sex reversal syndrome with an XX karyotype, the most common cause is a translocation . Translocation is the rearrangement of chromosomal material between non-homologous chromosomes. Sex reversal syndrome, also known as disorder of sex development (DSD), arises when an individual's chromosomal, gonadal, and phenotypic sex do not align. In gonadal sex reversal syndrome with an XX karyotype, a translocation involving the SRY (Sex-determining Region Y) gene can cause the gene to be present on an X chromosome. Because the SRY gene initiates male development, its translocation to the X chromosome can cause individuals with an XX karyotype to develop testes rather than ovaries. Reference: https://afju.springeropen.com/articles/10.1186/s12301-021-00210-5

Answer- A.�8 year Precocious puberty�in a girl is the appearance of any of the secondary sexual characteristics before the age of 8 years or the occurrence of menarche before the age of 10 years. Precocious puberty�in boys is the onset of secondary sexual characteristics before the age of nine years.�

Bartholin’s gland is situated in the superficial perineal pouch and measures about 0.5 cm. The duct measures 2 cm. The gland is compound racemose and lined by columnar epithelium. During sexual excitement, it secretes abundant alkaline mucus which helps in lubrication. Duct opens outside the hymen at the junction of the anterior two-third and posterior one-third in the groove between the hymen and the labium minus. The duct is lined by columnar epithelium except near the opening, where it is lined by stratified squamous epithelium. The Bartholin’s gland corresponds to the bulbourethral gland of male. Reference: D C Dutta’s textbook of gynecology, 7th edition, chapter 1

Genes for male development SRY gene-Master Gene for testis development SOX 9-SRY & SOX 9 induce testis to form FGF-9 (chemotactic factor) FGF-9 causes tubules from mesonephric duct to penetrate gonadal ridge SF1 (steroidogenic factor)-It stimulates differentiation of sertole or leydig cells WNT-4 is an ovary-determining gene. This gene upregulates DAXI-which inhibits the fraction of SOX 9 in females. Reference: Langman embryology 12/e, pg. 246-247

Luteal Phase Defect During normal luteal phase, when there is adequate progesterone secretion by the corpus luteum, adequate development of secretory endometrium occurs for blastocyst implantation. Luteal phase defect refers to a condition when production of progesterone is suboptimal by corpus luteum. Inadequate progesterone secretion could be due to: Inadequate follicular development Inadequate FSH or LH secretion Hyperprolactinemia Reference: Novak 14 th /ed p 1225, 15 th /ed p 1161

Vagina has dual origin Upper 2/3 → from fused mullerian duct Distal 1/3 → from bilateral sinovaginal bulbs , which are cranial evaginations of the urogenital sinus. Junction of these two is called vaginal plate (forms hymen) Reference: williams obstetrics 26th edition chapter 3

Indications for using Synthetic GnRH In females: (In all those conditions where there is increased estrogen, GnRH analogues are useful). In males: Cryptorchidism: short-term intranasal nafarelin is used. Carcinoma prostate: GnRH agonists are as effective as orchidectomy in Ca prostate but if there are neurological symptoms or life-threatening metastatic disease - androgens should first be started followed by GnRH agonist. BPH: Daily administration of leuprorelin or nafarelin decreases obstructive urinary symptoms in 1-6 monthstime. Reference: Jeffcoate 7 th /ed p 652