Sandbox Reserved 1120: Difference between revisions
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== Diseases== | == Diseases== | ||
=== Swyer syndrome (AKA XY gonadal dysgenis) | === Swyer syndrome (AKA XY gonadal dysgenis)=== | ||
If the TDF protein is not able to bind its targeted DNA sequences, the genes responsible for the testis development are not expressed. The patient owning this defective protein will then develop female characters, even though he has a XY karyotype. This phenomenon is known as the "Swyer Syndrome". | If the TDF protein is not able to bind its targeted DNA sequences, the genes responsible for the testis development are not expressed. The patient owning this defective protein will then develop female characters, even though he has a XY karyotype. This phenomenon is known as the "Swyer Syndrome". | ||
Different causes can explain this "XY gonadal dysgenis", as it is also called. About thirty mutations (named [http://www.uniprot.org/uniprot/Q05066#sequences "SRXY1"]) in the SRY gene have been shown to drive this phenotype development. It can also be due to crossovers during a meiosis. If a Y chromosome portion carrying the SRY gene is recombined into a X chromosome, a sperm cell will get this abnormal Y chromosome. If it then fecundates, a XY karyotype without any SRY gene will be formed. | Different causes can explain this "XY gonadal dysgenis", as it is also called. About thirty mutations (named [http://www.uniprot.org/uniprot/Q05066#sequences "SRXY1"]) in the SRY gene have been shown to drive this phenotype development. It can also be due to crossovers during a meiosis. If a Y chromosome portion carrying the SRY gene is recombined into a X chromosome, a sperm cell will get this abnormal Y chromosome. If it then fecundates, a XY karyotype without any SRY gene will be formed. | ||
=== De La Chapelle syndrome (AKA XX male syndrome) | === De La Chapelle syndrome (AKA XX male syndrome)=== | ||
From the meiosis just described would also result an abnormal X chromosome, carrying the SRY gene. If the sperm cell owning this chromosome fecundates an ovule, the resulting newborn will have a XX karyotype but a male phenotype. This is called the "De La Chapelle syndrome". In this case, the patient can either develop testis or both testis and ovarian tissues. As some epigenetic mechanisms can inactivate the X chromosome carrying SRY, this syndrome keeps most of the patients sterile<ref>PMID: 4622299</ref>. | From the meiosis just described would also result an abnormal X chromosome, carrying the SRY gene. If the sperm cell owning this chromosome fecundates an ovule, the resulting newborn will have a XX karyotype but a male phenotype. This is called the "De La Chapelle syndrome". In this case, the patient can either develop testis or both testis and ovarian tissues. As some epigenetic mechanisms can inactivate the X chromosome carrying SRY, this syndrome keeps most of the patients sterile<ref>PMID: 4622299</ref>. | ||
