Genetic Disorders - Sex Chromosome Disorders Flashcards
Which is more common - sex chromosome or autosome disorders?
Sex chromosome - more tolerated
2 factors of sex chromosome disorders?
- Lyonization of all but 1 x chromosome
2. Modest amount of genetic material carried by Y chromosome
What is the Lyon Hypothesis?
Only 1 X chromosome is active!
With the Lyon Hypothesis, when are the rest of the X chromosomes inactivated?
5th day gestation
How is one X chromosome inactivated?
Heteropyknosis
Normal females are mosaics which means?
1 set of cells with inactivated maternal X
1 set of cells with inactivated paternal X
What is the inactive X called morphologically?
Barr body
Barr body
Inactive X
- small mass in contact with nuclear membrane
Small mass in contact with nuclear membrane is probably?
Barr body
- Inactive X
Can some genes escape X inactivation?
Yes
Presence of a Y chromosome =
Male
If there is increased number X chromosomes, what will increase?
Intellectual disability
Severe intellectual disability correlates with more?
X chromosomes
Hermaphrodite
Presence of BOTH testicular tissue and ovarian tissue
Presence of BOTH testicular tissue and ovarian tissue
Hermaphrodite
Female Pseudohermaphrodite
Ovarian tissue with male external genitalia
Male Pseudohermaphrodite
Testicular tissue with female external genitalia
Klinefelter
47 XXY
47 XXY
Klinefelter
Most common cause of male hypogonadism?
Klinefelter
When does hypogonadism usually get diagnosed?
After puberty
Symptoms of Klinefelter
Long legs, small testes and small penis, gynecomastia, Low IQ, lack male characterisitics
Klinefelter men lack?
Male characteristics
Long legs, small testes and small penis, gynecomastia
Klinefelter
What metabolic and bone diseases are those with Klinefelter more at risk of developing?
Type 2 DM and metabolic syndrome
Osteoporosis
What type of tumors/cancers are those with Klinefelter more at risk of developing?
Teratomas, breast cancer
– Extragonadal germ cell tumors
Which sex chromosomal disorder is at risk of developing SLE?
Klinefelter
Turner Syndrome
45 X
45 X
Turner Syndrome
Most common sex chromosomal abnormality in females?
Turner Syndrome
If Turner syndrome patients have some Y chromosome sequences, what are they are risk for developing?
Gonadoblastoma
Physical finding of those with Turner Syndrome at birth?
Cystic hygroma
= edema swelling at neck
With Turner syndrome, what does the cystic hygroma turn into?
Bilateral neck webbing
Symptoms of Turner Syndrome?
Bilateral neck webbing, short stature, amenorrhea, streak ovaries
Bilateral neck webbing, short stature, amenorrhea, streak ovaries
Turner Syndrome
What are streak ovaries?
Fibrotic ovaries seen with Turner syndrome
What cardiovascular abnormalities are common in Turner Syndrome?
Coarctation of aorta
Bicuspid aortic valve
