Sex Chromosome Aneuploidies ✅ Flashcards
What chromosome determines maleness?
The Y chromosome
What is the implication of the Y chromosome determining maleness when considering sex chromosome aneuploidies?
A person is male if he has a Y chromosome, regardless of how many X chromosomes are present
Give 2 sex chromosome aneuplodies
- Turner’s syndrome
- Klinefelter’s syndrome
What kind of chromosomal abnormality is Turner’s syndrome?
Monosomy
What is significant about Turner’s syndrome being an monosomy?
It is the only survival monosomy
What happens to most fetuses with Turner’s syndrome?
They abort spontaneously
What abnormality may be seen with surviving fetuses with Turner’s syndrome?
They can be grossly hydropic
What is the genotype of Klinefelter’s syndrome?
XXY
What is the prevalence of Klinefelter’s syndrome?
1 in 500 males
How might babies and young children with Klinefelter’s syndrome present?
- Hypospadias
- Micropenis
- Cryptorchidism
- Developmental delay
How might school aged children with Klinefelter’s syndrome present?
- Language delay
- Learning difficulties
- Behaviourial problems
How may older children with Klinefelter’s syndrome present?
- Incomplete pubertal development
- Gynaecomastia
- Small testes
Is Klinefelter’s syndrome always diagnosed in childhood?
No, may be diagnosed in later life
What increases the chances of Klinefelter’s syndrome not being diagnosed until later life?
Some boys with this condition have normal facial features
How might adults with Klinefelter’s syndrome present?
Infertility
