As the WNT4 gene is essential for developing a protein that is essential for female sex development, the Müllerian duct is either absent or deformed when this gene is not present. The development of the female reproductive system may be disrupted in the absence of the WNT4 proteins regulation. Abnormal androgen production is also induced, eventually leading to hyperandrogenism and Müllerian aplasia. Bardet-Biedl Syndrome
Bardet-Biedl syndrome (BBS) is a ciliopathic human genetic disorder that can affect various parts of the body. Parts of the urogenital system where the effects of BBS are seen include: ectopic urethra, kidney failure, uterus duplex, hypogonadism, septate vagina, and hypoplasia of the fallopian tubes, uterus, ovaries. Some of the common characteristics associated with this syndrome include intellectual disorders, loss of vision, kidney problems, and obesity.The mechanism that causes BBS is still remains unclear. Mutations in more than 20 genes can cause BBS and is an inherited recessive condition. Some of the gene mutations that occur in BBS are listed below:
BBS1, BBS2, ARL6 (BBS3), BBS4, BBS5, MKKS (BBS6), BBS7, TTC8 (BBS8), BBS9, BBS10, TRIM32 (BBS11), BBS12, MKS1 (BBS13), CEP290 (BBS14), WDPCP (BBS15), SDCCAG8 (BBS16), LZTFL1 (BBS17), BBIP1 (BBS18), IFT27 (BBS19), IFT72 (BBS20), and C8ORF37(BBS21) The majority of the genes that are related to BBS encode proteins which are called cilia and basal bodies, which are related structures. Fraser Syndrome
Fraser syndrome is a disorder that affects the development of the child prior to birth. Infants born with Fraser syndrome often have eyes that are malformed and completely covered by skin.
The McMredie-McBride hypothesis explains that the limbs of the infants become malformed as a result of the thalidomide harming the neural tissue—simply because the neural tissue has such a large impact on formation and development of the limbs. Causes
Thalidomide
Thalidomide was released onto the market in 1958 in West Germany under the name Contergan. Primarily prescribed as a sedative or hypnotic, thalidomide also claimed to cure "anxiety, insomnia, gastritis, and tension". Afterwards it was used against nausea and to alleviate morning sickness in pregnant women. Thalidomide became an over-the-counter drug in Germany around 1960, i.e. it could be bought without a prescription. Shortly after the drug was sold, in Germany between 5,000 and 7,000 infants were born with phocomelia. Only 40% of these children survived.Research also proves that although phocomelia did exist through the 1940s and 1950s cases of severe phocomelia multiplied in the 1960s when thalidomide was released in Germany; the direct cause was traced to thalidomide. The statistic was given that "50 percent of the mothers with deformed children had taken thalidomide during the first trimester of pregnancy." Throughout Europe, Australia and the United States 10,000 cases were reported of infants with phocomelia; only 50% of the 10,000 survived. Thalidomide became effectively linked to death or severe disabilities among babies. Those subjected to thalidomide while in the womb experienced limb deficiencies in that the long limbs either were not developed or presented themselves as stumps. Other effects included deformed eyes, hearts, alimentary and urinary tracts, blindness and deafness.