Genetics

Question 1

What is aCGH used for?

Answer 1

chromosome deletions/duplications

Question 2

What is next generation sequencing for?

Answer 2

more specific parts of DNA - i.e. need to know what you’re looking for

Question 3

When can cardiac malformations be seen on scans?

Answer 3

12-20 weeks

Question 4

When can microcephaly be seen on scans?

Answer 4

> 22 weeks

Question 5

When can short limbs be seen on scans?

Answer 5

> 22 weeks

Question 6

What is required to do a DNA test on a baby in utero?

Answer 6

need tissue with the same genetic make up

Question 7

What is chorionic villious sampling a biposy of?

Answer 7

placenta

Question 8

What is amniocentesis a “biopsy” of?

Answer 8

skin/urine cells

Question 9

What is pre implantation genetic testing?

Answer 9

performing genetic tests on an embryo before reimplanting it with the correct genotype

Question 10

How is pre implantation genetic testing done?

Answer 10

use FISH to highlight chromosomes X,Y, 18

requires an IVF like procedure

Question 11

When is pre implantation genetic testing considered?

Answer 11

if there is a parental chromosome abnormality or X linked disorder

Question 12

What is Non Invasive Pre Natal Testing (NIPT)?

Answer 12

analyses free foetal DNA in the mothers circulation

Question 13

What is Non Invasive Pre Natal Testing (NIPT) used for?

Answer 13

sex determination and trisomy testing

Question 14

What is the problem with NIPT?

Answer 14

you can get false positives - due to the palcenta having patchy chromosomal abnormalities - always best to do a few tests

Question 15

What is confined placental mosaicism?

Answer 15

the palcenta having patchy chromosomal abnormalities

Question 16

What is a chromosome microarray?

Answer 16

1st line for chromosome abnormalities
rapid and high resolution
but doesnt pick up balanced translocations

Question 17

What are the signs of a floppy baby?

Answer 17

lack of head control
increased range of movements
frogged legged
possible breathing difficulties

Question 18

What most commonly causes a floppy baby?

Answer 18

central problems - intracranial haemorrhage, hypoxic ischaemic encephalopathy, cerebral malformations, chromosomal abnormalities, congenital infections

Question 19

Name some common congenital infections? (TORCH)

Answer 19

Toxoplasmosis
Others - syphilis, varcella zoster, parovirus
Rubella
Cytomegalovirus
HIV, Hepatitis, Herpes