Chromosome Disorders

Question 0

What chromosomal disorder has a recurrence risk of 1/800?

Answer 0

Trisomy 21-47, XY or XX, +21 “Down syndrome”

Question 1

What chromosome disorder is caused by aneuploidy, nondisjunction at c21, usually at maternal meiosis 1

Answer 1

Trisomy 21-47, XY or XX, +21 “Down syndrome”

Question 2

The following phenotype is characteristic of what chromosomal disorder:
- congenital hypotonia, facial dysmorphology, moderate mental retardation, communication disorder, 40% congenital heart disease hearing loss due to otitis, media strabismus and refractive errors, hypothyroidism, upturned palpebral fissures,1st and 2nd toe gap

Answer 2

Trisomy 21-47, XY or XX, +21 “Down syndrome”

Question 3

In what chromosomal disorder are 95% of trisomies due to maternal nondisjunction, 95% non familial?

Answer 3

Trisomy 21-47, XY or XX, +21 “Down syndrome”

Question 4

What chromosomal disorder is caused by aneuploidy, fusion of acrocentric chromosomes near the centromere w/ loss of short arms, 14p and 21 (parent = 45c)

Answer 4

Robertsonian Translocation - 46, XY or XX, t (14,21)

Question 5

The following phenotype is characteristic of what chromosomal disorder:
- hypotonia, facial dysmorphology, moderate mental retardation, communication disorder, 40% congenital heart disease, hearing loss due to otitis media, strabismus and refractive errors, hypothyroidism, 1st and 2nd toe gap

Answer 5

Robertsonian Translocation - 46, XY or XX, t (14,21)

Question 6

What chromosomal disorder is 4% of trisomies and karyotype of parents?

Answer 6

Robertsonian Translocation - 46, XY or XX, t (14,21)

Question 7

What chromosomal disorder has a mixture of normal cells and trisomic cells?

Answer 7

Mosaic trisomy

Question 8

What chromosomal disorder represents 1% of trisomies?

Answer 8

Mosaic Trisomy

Question 9

What chromosomal disorder has aneuploidy nondisjunction of c18?

Answer 9

Trisomy 18 “Edwards syndrome”

Question 10

What chromosomal disorder has a 1/5000 to 1/7500 recurrence risk?

Answer 10

Trisomy 18 “Edwards syndrome”

Question 11

What chromosomal disorder has the following phenotype:
- short sternum, overlapping fingers w/ clenched fist, genital anomaly and left foot with missing digits, cardiac defect, renal anomaly, severe mental retardation, facial features: low frontal hairline, short palpebral fissures, blunt nasal tip w/ small nostrils, small chin, high nasal bridge, fawn like ears?

Answer 11

Trisomy 18 “Edwards syndrome”

Question 12

What chromosomal disorders are semi lethal?

Answer 12

Trisomy 18 “Edwards syndrome”

Trisomy 13 “patau’s syndrome”

Question 13

What chromosomal disorder has aneuploidy nondisjunction of c13?

Answer 13

Trisomy 13 “patau’s syndrome”

Question 14

What chromosomal disorder has a recurrence risk of 1/10,000 to 1/20,000?

Answer 14

Trisomy 13 “patau’s syndrome”

Question 15

What chromosomal disorder has the following phenotype:
- holoprosencephaly w/ premaxillary agenesis (cleft lip/palate), microphthalmia, fixed fingers, polydactyly, cryptochidism, abnormal scrotum, cardiac defect, cystic kidneys, short prominent sternum, omphalocele, micropenis, rocker bottom feet

Answer 15

Trisomy 13 “patau’s syndrome”

Question 16

In what chromosomal disorder is it necessary to karyotype the parents?

Answer 16

Trisomy 13 “patau’s syndrome”

Question 17

What chromosomal disorder has a 100% transmittance from carrier to offspring?

Answer 17

Trisomy 21-46, XX or XY, t(21,21)

Question 18

What chromosomal disorder has nondisjunction of c8 in some cells only?

Answer 18

Trisomy 8 mosaic -46

Question 19

What chromosomal disorder has the following phenotype:

- facial dysmorphology, strabismus (esotropia), moderate mental retardation?

Answer 19

Trisomy 8 mosaic -46

Question 20

In what chromosomal disorder is the full trisomy 8 lethal?

Answer 20

Trisomy 8 mosaic -46

Question 21

In what chromosomal disorder is he zygote dispermy or polar body retained?

Answer 21

Triploidy - XXX

Question 22

The following phenotype is characteristic of what chromosomal disorder:
- severe growth restriction, syndactyly, dysmorphic fetus

Answer 22

Triploidy - XXX

Question 23

What chromosomal disorder is 100% fatal?

Answer 23

Triploidy - XXX

Question 24

In what chromosomal disorder does the affected individual receive 3 copies of every chromosome?

Answer 24

Triploidy - XXX

Question 25

What are examples of chromosomal disorders?

Answer 25

Trisomy 21-47, XY or XX, +21 (Down's Syndrome)
Robertsonian Translocation-46, XY or XX, t(14,21)
Mosaic Trisomy
Trisomy 18 "Edward's Syndrome"
Trisomy 13 "Patau's Syndrome"
Trisomy 21-46, XX or XY, t(21,21)
Trisomy 8 mosaic -46
Triploidy- XXX