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Questions and Answers
What is the primary focus when classifying disorders of sex development?
What is the primary focus when classifying disorders of sex development?
- Using descriptive terms based on the observed characteristics. (correct)
- Avoiding any reference to the karyotype to prevent confusion.
- Prioritizing chromosomal abnormalities over phenotypic traits.
- Referring to the karyotype of the individual.
A mosaic individual with a disorder of sex development has:
A mosaic individual with a disorder of sex development has:
- Uniform cell populations with identical genetic material.
- Cell populations derived from two separate individuals after fusion of zygotes.
- A complete absence of cell division due to mitotic errors.
- Different cell populations originating from the same individual. (correct)
Polled Intersex Syndrome (PIS) in goats is related to which genetic condition?
Polled Intersex Syndrome (PIS) in goats is related to which genetic condition?
- Dominance of the horned gene.
- Homozygosity for the polled gene. (correct)
- Heterozygosity of the polled gene.
- Recessive inheritance of the intersex gene.
What is a key characteristic of Freemartinism in cattle?
What is a key characteristic of Freemartinism in cattle?
In goats affected by Polled Intersex Syndrome, what is typically observed regarding the presence of SRY gene?
In goats affected by Polled Intersex Syndrome, what is typically observed regarding the presence of SRY gene?
The term 'freemartin' is derived from:
The term 'freemartin' is derived from:
What is the primary effect of AMH (Anti-Müllerian Hormone) in Freemartinism?
What is the primary effect of AMH (Anti-Müllerian Hormone) in Freemartinism?
What vascular event primarily contributes to the development of Freemartinism?
What vascular event primarily contributes to the development of Freemartinism?
In dogs with Persistent Mullerian Duct Syndrome (PMDS), what inheritance pattern is typically observed?
In dogs with Persistent Mullerian Duct Syndrome (PMDS), what inheritance pattern is typically observed?
Which diagnostic method involves identifying a specific fragment from the Y-chromosome?
Which diagnostic method involves identifying a specific fragment from the Y-chromosome?
What is the significance of the absence of PISRT1 and FOXL2 genes in goats?
What is the significance of the absence of PISRT1 and FOXL2 genes in goats?
Why is consideration of karyotype useful, but unnecessary references to karyotype should be avoided?
Why is consideration of karyotype useful, but unnecessary references to karyotype should be avoided?
What is the most common chromosomal sex in goats affected by Polled Intersex Syndrome (PIS)?
What is the most common chromosomal sex in goats affected by Polled Intersex Syndrome (PIS)?
What is the typical presentation of intersexes in the context of Polled Intersex Syndrome (PIS)?
What is the typical presentation of intersexes in the context of Polled Intersex Syndrome (PIS)?
Which cellular process can lead to mosaicism in individuals with disorders of sex development (DSDs)?
Which cellular process can lead to mosaicism in individuals with disorders of sex development (DSDs)?
In freemartin diagnosis, what vaginal length measurement would indicate the presence of Freemartinism in a calf up to 30 days old?
In freemartin diagnosis, what vaginal length measurement would indicate the presence of Freemartinism in a calf up to 30 days old?
What is the primary reason that a higher proportion of chimeric males might be culled compared to non-chimeric males?
What is the primary reason that a higher proportion of chimeric males might be culled compared to non-chimeric males?
What is the role of the Sertoli cells in the development of Freemartinism?
What is the role of the Sertoli cells in the development of Freemartinism?
How would you classify an individual with cell populations from different individuals and the fusion of two zygotes?
How would you classify an individual with cell populations from different individuals and the fusion of two zygotes?
Which hormone is the main driver of the testis development?
Which hormone is the main driver of the testis development?
What effect does Freemartinism have on a female in cattle?
What effect does Freemartinism have on a female in cattle?
What can clinical signs tell someone about animal infertility?
What can clinical signs tell someone about animal infertility?
What does the AMX/Y Diagnostic test search for?
What does the AMX/Y Diagnostic test search for?
Which cattle abnormality presents itself in males only?
Which cattle abnormality presents itself in males only?
What vascular even leads to Freemartinism in cattle?
What vascular even leads to Freemartinism in cattle?
Where do researchers believe Polled and PIS Genes come from?
Where do researchers believe Polled and PIS Genes come from?
Which of the following is NOT a key attribute of freemartinism?
Which of the following is NOT a key attribute of freemartinism?
If you examined a set of newborn calves, whose parents have histories of Freemartinism, which radioimmunoasssay would confirm Freemartinism?
If you examined a set of newborn calves, whose parents have histories of Freemartinism, which radioimmunoasssay would confirm Freemartinism?
Flashcards
What are DSD's?
What are DSD's?
Disorders of sex development, based on human DSD's with 46 chromosomes.
What is a Chimera?
What is a Chimera?
Cell populations from different individuals; possibly a fusion of two zygotes.
What is a Mosaic?
What is a Mosaic?
Different cell populations, but from the same individual, may be caused by mitotic errors.
What is Persistent Mullerian Duct Syndrome (PMDS)?
What is Persistent Mullerian Duct Syndrome (PMDS)?
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What is Goat Polled Intersex?
What is Goat Polled Intersex?
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Which goats are predisposed to Polled Intersex?
Which goats are predisposed to Polled Intersex?
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What causes Polled Intersex Syndrome (PIS) genes?
What causes Polled Intersex Syndrome (PIS) genes?
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What is Freemartinism?
What is Freemartinism?
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What happens in Freemartinism?
What happens in Freemartinism?
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Are AMH levels important in development?
Are AMH levels important in development?
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How to diagnose Freemartinism?
How to diagnose Freemartinism?
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Name examples of 46,XY DSD
Name examples of 46,XY DSD
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What is 45,X DSD?
What is 45,X DSD?
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Study Notes
Disorders of Sex(ual) Development
- Intersex refers to ambiguous genitalia.
Learning Objectives
- Understand the polled intersex syndrome in goats
- Understand the aetiology, diagnosis, and effects of Freemartinism in cattle
Disorders of Sex Development
- Based on human DSDs having 46 chromosomes.
Revised Nomenclature for DSD
- Karyotype classification should be avoided in favor of descriptive terms like "androgen insensitivity syndrome."
- AMH is Anti-Mullerian Hormone
- CAIS is Complete Androgen Insensitivity Syndrome
- DSD is Disorders of Sex Development
- MURCS is Mullerian, Renal, Cervicothoracic Somite Abnormalities
- PAIS is Partial Androgen Insensitivity Syndrome
- POR is Cytochrome P450 oxidoreductase.
Chimera vs Mosaic
- Chimera involves cell populations from different individuals, possibly from the fusion of two zygotes
- Mosaic involves different cell populations from the same individual, possibly with mitotic errors
Inherited Disorders in Sexual Development
- Further details can be found in Table 1.
Persistent Mullerian Duct Syndrome (PMDS)
- An example of a DSD
- Mullerian ducts fail to regress.
- Affected miniature schnauzers can have oviducts, uterine horns, uterine body, cervix, and cranial vagina
- Also posses male internal and external genitalia
- Approximately 50% are cryptorchid
- In miniature schnauzers it is inherited as a simple autosomal recessive trait with expression limited to XY males
- Affected embryos produce MIS throughout the critical period for Mullerian duct regression
Goat Polled Intersex
- Characterized as a 'sex reversed' female without the SRY gene.
- Mainly observed in Saanen goats.
- Wide variety in presentation, including feminization.
Genetics of Goat Polled Intersex
- Polled (P) is dominant (Chromosome 1).
- Intersex condition is related to homozygosity for the polled gene
- A horned male must be homozygous pp.
- Offspring will have at least one 'p' allele
- Features a 60XX karyotype ('male') without the SRY gene.
- Testes are invariably present.
- Both male and female genitalia are observed.
- AMH is produced from Sertoli cells
- Limited development of the uterus.
- Polled and PIS genes are close on chromosome 1.
- Absence of PISRT1 and FOXL2 genes is noted.
- Freemartinism occurs in goats (and sheep.).
- Mainly observed in dairy goats like Saanen, Toggenburg, and Alpine breeds.
- Intersexes display both male and female phenotypic traits.
- XX chromosomal sex.
- There is wide phenotypic expression: normal male to normal female.
- Influenced by PISRT1 and FOXL2 genes.
Freemartinism in Cattle Definition
- Infertility in a female born co-twin to a male
- Occurs in approximately 90% of cattle twin pregnancies with both a male and female fetus
- Can occur in other species as well.
- Derivation of the name: Frei = barren, Mart = an animal killed at Martinmas
Historical Context
- The condition was reported by John Hunter in 1779.
- Etiology was discovered in the early 1900s.
Pathophysiology
- Fusion of allantochorionic membranes.
- Vascular anastomoses leading to mixing of vascular content.
- Mixing of cells
- Mixing of hormones, especially AMH.
- Male embryo develops prior to the female.
- AMH secreted by the Sertoli cells prevents/decreases the growth of the paramesonephric ducts.
- Mullerian duct and gonads are not developed.
- Genital swelling is normal
- Vulva and vestibule are small
Fertility
- Male fertility is also likely affected.
- Testicular degeneration occurs histologically.
- Higher proportion of chimeras were culled because of poor fertility than normal controls
Diagnosis
- Includes history of being a twin (>90% of cases).
- Clinical signs include infertility
- Lack of a palpable cranial reproductive tract.
- Laboratory diagnostics include: PCR for Y chromosome, karyotype (XX/XY requires sufficient lymphocyte exam).
Prevalence
- 2 heifer/4cows= 50%= same as singles
Other Species
- Ovine (sheep)
- Caprine
- Cervidae (deer)
- Porcine (pigs)
- Equine (horses)
- Camelids
- Humans
Disorders of Sex Development Summary
- Freemartinism in cattle involves an infertile heifer born co-twin to a male
- Polled Intersex in goats involves a polled genetic female with male genitalia
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