17-KSR Deficiency

17-KSR deficiency or 17-beta hydroxysteroid dehydrogenase III deficiency is an intersex variation that affects 1 in 147,000 newborn CTM or AMAB individuals (however, those with this variation are also sometimes incorrectly assigned female at birth).

Most individuals with this variation have a vagina, ambiguous genitals, or a micropenis instead of an average penis (despite their wolffian chromosomes). Those who do have an average penis usually have an oddly placed urethra. Because of this, they often also have hypogonadism and aromatase excess syndrome. All individuals with this variation have testicles. Depending on their type of genitalia, testes may be undescended (cryptorchidism), in the inguinal canal, or within the labia.

Hypothyroidism occasionally occurs in those with this variation as well.

Upon puberty, individuals with this variation usually gain muscle mass and have a deepening voice, facial and body hair, and possibly breasts as well. They are unable to produce fertile sperm, making them infertile.

Causes

This variation occurs when the HSD17B3 gene does not properly provide instructions to an active enzyme in testicle production. Because of this, one does not produce testosterone at the same level as wolffians and thus has more femininized traits outwardly.

History

This variation was originally described in 1971 by Saez and his colleagues.

17-KSR deficiency in Israel

In a specific area within Israel, incest and inbreeding are highly common, which causes the genetic development of many individuals to turn out in an unlikely manner. Because of this, 1 in every 100-150 individuals in this area were born with 17-KSR, which is a drastically high amount compared to the average rarity of the variation.

This does not mean that incestual relations are the reason for this variation, but rather means that it can intensify the likelihood of it in development.