Genetics

Question 1

what are Qualities of a good counsellor

Answer 1

• Respect and establish trust
• Confidentiality
• Patient autonomy / non-directiveness
• Empathic
• Non-judgmental attitude
• Patient advocate
• Individualization
• Sensitivity to language and cultural differences
• Role of health professional: ‘supportive’, ‘enabler

Question 2

what are Clinical signs of down syndrome

Answer 2

• Short palpebral fissures
• Small nose
• Flattened face
• Smooth philtrum
• Thin upper lip
• Upward slanting eyes
• small eyes
• short neck
• One crease in the palm of their hand (palmar crease).

they are at risk of leukaemia and alzhemiers when older

Question 3

what are other features of Down syndrome

Answer 3

• Poor/weak muscle tone
• Impaired intellectual ability
• Heart defects

Question 4

name screening tests for Down syndrome

Answer 4

Ultrasound
Maternal serum screening
non-invasive parinatal screening(NIPS/NIPT)

Question 5

WHEN Can you use each of the screening tools for Down syndrome

Answer 5

Ultrasound in first trimester: nuchal translucency scan 11-13weeks. Increased NT
detects 75% T21 cases.
- Maternal serum screening: 15-18 weeks, triple test (AFP, BhCG, oestradiol), 60%
T21
- Ultrasound in second trimester: 18-23 weeks, FA scan
- Non-invasive perinatal screening (NIPS/NIPT): >10 weeks, cell free DNA in
maternal blood, most accurate for T21

Question 6

what are the SCREENING tests for Down syndrome

Answer 6

Ultrasound in first trimester: nuchal translucency scan 11-13weeks. Increased NT
detects 75% T21 cases.
- Maternal serum screening: 15-18 weeks, triple test (AFP, BhCG, oestradiol), 60%
T21
- Ultrasound in second trimester: 18-23 weeks, FA scan
- Non-invasive perinatal screening (NIPS/NIPT): >10 weeks, cell free DNA in
maternal blood, most accurate for T21

Question 7

what can you look at for diagnosing Down syndrome

Answer 7

karyotype and QF-PCR

Question 8

Why a couple might battle to decide whether to have testing done or not

Answer 8

• Risks associated with screening
• Religious beliefs
• Denial
• Differing opinions

Question 9

Which medications are contraindicated in pregnancy

Answer 9

 Roaccutane
 Warfarin
 Carbamazepine

Question 10

what are teratogenic factors

Answer 10

o Medications - Drug categories
o Contraindicated
 Roaccutane
 Warfarin
 Carbamazepine
o Infections
 TORCH
o Maternal illness
 Uncontrolled diabetes

Question 11

what happens in FDA category C

Answer 11

Risk cannot be ruled out, potential benefits may justify potential risk

Question 12

what happens in FDA category A

Answer 12

no risk is shown in the drug

Question 13

what happens in FDA category X

Answer 13

the drug is contraindicated in pregnancy

Question 14

what are indications for genetic counselling

Answer 14

 Prenatal risk for Down syndrome: AMA or other screening
 Ultrasound identified abnormalities
 Family History of genetic condition – e.g. cystic fibrosis
 Previous abnormality – e.g. child with Down syndrome
 Exposure to teratogens
o Medications - Drug categories
o Contraindicated
 Roaccutane
 Warfarin
 Carbamazepine
o Infections
 TORCH
o Maternal illness
 Uncontrolled diabetes
 Consanguinity
 Increased risk of recessive conditions

Question 15

what is the deal with advanced maternal age and which age group is that

Answer 15

women above the age of 35

o The risk of chromosomal abnormalities of a fetus increases with increasing age of the
mother.
o Older women have a greater chance of underlying disease that may increase the risk
of congenital abnormalities in their offspring, e.g. Diabetes Mellitus

Question 16

Ultrasound in second trimester - Fetal anomaly (FA) scan (18 to 23 weeks

Answer 16

o Soft markers, e.g.
o Echogenic bowel
o Short femur
o Short humerus
o Nuchal fold more than 6mm
o Hypoplastic nasal bone
o Hydronephrosis
o Major abnormalities e.g.
 cardiac defects
 Neural tube defects

Question 17

Maternal serum screening

Answer 17

o 15-18 weeks
o “triple test”- AFP, BhCG, Oestradiol
o T21 - 60% <35 / 75-90% >35 T18 - 60 –75%)
o 4 in 1 test- adds dimeric inhibin A (increases detection +- 10%)
o Increased AFP – useful in detection of open NTD’s
o Not offered in the state system

Question 18

Ultrasound in first trimester

Answer 18

o Nuchal Translucency scan:
o 11 – 13 weeks
o Increased NT - Detects up to 75% Down syndrome
o Combined with and BhCG PAPP-A (85% )
o Combined with presence/absence of nasal bone (95%)
o New U/S markers being added
o (5% false +)
o Major abnormalities (e.g. anencephaly)

Question 19

SCREENING TESTS VS DIAGNOSTIC TESTS

Answer 19

Screening tests are non-invasive and are used for prenatal screening. Only give us an
indication as to how likely it is that the fetus has a specific condition. Screening tests can
identify cases that may benefit from diagnostic testing. Diagnostic tests can provide a clear
diagnosis, but are associated with a risk of miscarriage.

Question 20

DIAGNOSTIC TESTS

Answer 20

 Foetal karyotype obtained by:
o Chorionic villus sampling (CVS)
 11-13 weeks
 1-2% risk of miscarriage
 Results: 2-3 weeks
o Amniocentesis
 16-20 weeks
 1 in 500 risk of miscarriage
 Results: 72 hours or 3 weeks depending on test
o Cordocentesis
 After 20 weeks
 2% risk of miscarriage
 Results: 3 days

Question 21

Karyotype

Answer 21

o Results takes 2 to 3 weeks
o Cells are cultured
o Full karyotype
o Provide information on numerical and structural abnormalities of all chromosomes
o Indicated when multiple abnormalities are detected on ultrasound

Question 22

QF-PCR

Answer 22

o Result within 72 hours
o No culture required
o Also only give info about possible trisomy 13,18, 21 and sex chromosomes
o Can’t distinguish between trisomy and translocations
o Indicated when one of the above trisomies are suspected

Question 23

FISH (Fluorescent In Situ Hybridization)

Answer 23

o can be requested for quick result (2-3 days)
o Will only give info about possible trisomy 13,18, 21 and sex chromosomes.
o Not full karyotype
o Indicated when one of the above trisomies are suspected

Question 24

TOP ACT - CHOICE ON TERMINATION OF PREGNANCY ACT, 1996 (ACT NO. 92, 1996.)

Answer 24

• First 12 weeks – upon request
• 13-20 weeks – a medical practitioner in consultation with the woman finds a :
  – Risk of injury to the physical or mental health of the woman
  – Substantial risk of severe physical or mental abnormality to the fetus
  – Rape or incest
  – Significant effect to the social or economic circumstances of the woman
• After 20 weeks - a medical practitioner, after consultation with another medical practitioner
  or a registered midwife, finds that the pregnancy will:
  – Endanger the woman’s life
  – Result in severe malformation of the fetus
  – Pose risk of injury to the fetus

Question 25

Doctor/ genetic counsellor should provide:

Answer 25

o Non-directive genetic counselling on abnormal results
o Diagnosis and prognosis for the fetus
o Discussion of options related to pregnancy
* TOP (TOP act*)
* TOP for Down syndrome allowed up to 24 weeks
o Full implications of all choices
o Time for decision-making
o Supportive counseling

Question 26

The doctor/ genetic counsellor, at all times, must

Answer 26

o Maintain a non-judgmental attitude
o Accept the policy of freedom of choice
o Believe in the rights and worth of the individual
o Believe that people choose what is right for them in their situation, and according to
their values and beliefs
o Provide individualized counselling

Question 27

Grief response

Answer 27

o Denial, anger, bargaining, depression, acceptance
o Search for cause.
o Guilt
o May be couple differences in reaction to diagnosis

Question 28

Breaking bad news (After Robert Buckman’s six step protocol)

Answer 28

o Getting started
o How much does the patient know
o How much does the patient want to know
o Information sharing
o Responding to feelings
o Planning and follow-up