Question

In humans, XX males and XY Females are rare, such rare sexes are due to-

• A. Deletion of X chromosome
• B. Deletion of Y chromosome
• C. XY translocation
• D. Duplication of X chromosomes

Answer 1

The correct option is C XY translocation

• translocation results specific syndromes such as Down syndrome, Turner syndrome among others where the number of chromosome varies. In case of sex determination. The normal human male karyotype shows 46 XY and female 46 XX. However, the genotype-phenotype does not match always and there are phenotypically males with 46 XX and females with 46 XY. Such instances are very rare. • Males with 46 XX karyotype are referred as XX male syndrome or de la Chapelle syndrome. These individual are phenotypically male but are genetically female and the phenotype is clinically termed as XX male syndrome. The incidences are very rare (4 in 1 lakh). Individuals exhibit feminine characteristics, develop small testes, develop gynecomastia, without Müllerian tissue (that develop fallopian tubes, uterus, cervix, vagina etc in female),and are sterile. • Similarly, an individual having 46 XY does not always represent male characters; instead it may represent XY complete gonadal dysgenesis (CGD) or Swyer syndrome. Although, in these genetically male fetuses, the Y chromosome is present; gonads do not differentiate into active testes due to loss of SYR gene from Y chromosomes.. In such case the gonads represent as streak gonads without having ovarian or testicular tissue. Testosterone or antimüllerian hormone (AMH) does not produce due to lack of testis and therefore male sexual organs do not develop.