(ABGC) American Genetic Counseling Boards Review –
Questions & Answers
A young patient (5yrs) presents for the first time to a new dentist with
crowded teeth, making them very hard to clean. In further exploration of the
issue, she learns that the child had delayed eruption of his teeth. The patient's
mother also relays that her pediatrician has several times noted how
prominent the veins of his scalp are and his short stature. However, she thinks
that this is just part of the spectrum seen in their family given that she herself
is quite short and has fair skin, making it easier to see her veins. You speak
with the dentist who isn't sure whether or not to refer the family. You are
most concerned about what mutation:
LMNA G1138A
LMNA G608G
FGFR3 Exon 11 deletion
FGFR3 G608G Correct Ans - LMNA G608G
The current prenatal screening test used in your clinic has a sensitivity of 96%
and a specificity of 89%. In speaking to representatives from the lab, you learn
that they want to adjust their reading of this test by increasing the cutoff
levels. Which of the following effects would you expect to see if this change
was implemented?
i. Increase sensitivity
ii. Increase specificity
iii. Decrease false positives
iv. Decrease false negatives Correct Ans - ii, iii
Which of the following scenarios would MTHFR testing be appropriate?
a. Recurrent pregnancy loss
b. Thrombophilia, in the presence of negative primary thrombophilia testing
c. Open neural tube defect identified on prenatal ultrasound, despite adequate
folic acid intake
d. Patients about to start a methotrexate chemotherapy regimen
e. none of the above Correct Ans - None of the above are reasons that
MTHFR testing should be conducted
Genetic drift is an exception of which of the following assumptions of Hardy
Weinberg:
,a. No mutation
b. No migration
c. Population is infinitely large
d. Random mating Correct Ans - c
For which indication would telehealth service delivery model be
inappropriate?
Breast cancer
Marfan Syndrome
Carrier screening
Cascade testing Correct Ans - Marfan Syndrome (utility of testing
influenced by physical evaluation)
A couple is seen for preconception counseling. The woman's brother has
Gaucher disease, and she has Ashkenazi Jewish ancestry (Gaucher disease
incidence of 1 in 1,000). Before doing any genetic testing, which of the
following is closest to the risk of the couple having an affected child?
1/50
1/100
1/150
1/200 Correct Ans - 1/100
--With incidence of disease in AJ being 1/1000, man's carrier risk is about
1/18
--Woman's risk of being a carrier is 2/3 since her parents are obligate carriers
and she is not affected
-- ⅔ x ½ x 1/18 x ½ = 1/108 = ~1/100
You are meeting a 3 year old little boy in the pediatric genetics clinic. His
parents were referred to the clinic by his astute dentist who mentioned he did
not have as many teeth as expected. On meeting the boy, you also note he has
sparse hair. His parents also tell you he tends to get overheated when he plays
outside. Based on these findings, what is the most likely genetic cause of his
signs and symptoms?
a. Missense mutation in IKBKG
b. Deletion in OCA2
c. Missense mutation in EDA1
*The condition being described is hypohidrotic ectodermal dysplasia which is
most often caused by EDA1 mutations.
,d. Translocation interrupting SPRED1 Correct Ans - c. Missense
mutation in EDA1 *The condition being described is hypohidrotic ectodermal
dysplasia which is most often caused by EDA1 mutations.
A genetic counselor in the ophthalmology clinic is meeting with a family who
have a 12 year old son recently diagnosed with retinitis pigmentosa.
Throughout the appointment, the patient's father makes disparaging remarks
about blindness and his son being handicapped. The genetic counselor finds
herself to be annoyed and angry with the father. The genetic counselor has a
good friend with RP and she can't help but think about him as she talks with
the family. What best describes the behavior and feelings of the genetic
counselor?
a. Transference
b. Countertransference
c. Resistance
d. Resentment Correct Ans - b. Countertransference *The GC is
displaying countertransference as she is transferring her feelings and
experiences with RP in her friend onto the client/the family.
You are meeting with a 30 year old woman to discuss a family history of
reported Alport syndrome. She is hoping to start a family in the near future
and wishes to know her risk to have a child with the condition. After taking
the family history, you notice that only males are affected and there is no
male-male transmission. The patient's maternal uncle is affected. Based on
this family history, what is the highest recurrence risk you would quote for
this patient to have a child with Alport syndrome?
a. 50%
b. 25%
c. 12.5%
d. Less than 1% Correct Ans - c. 12.5%
Alport syndrome can be XLR, AD or AR. However, the most common form and
the form consistent with the pedigree is XLR. This means for the woman's
mom, there is a 50% chance she is a carrier. She has a 50% chance of passing
on that X to the patient. The patient has a 50% chance of passing that onto the
future child. Note, that because it's X linked, females with the condition may or
may not manifest in symptoms.
½ * ½ *½ = ⅛ or 12.5%
, A 12 year old female is referred to genetics after her PCP finds 5 café au lait
spots on physical exam. She also has freckling in her armpits. Which of the
following clinical findings would be most helpful for diagnosing her?
a. Learning disability
b. Lisch nodules
c. ADHD
d. Polydactyly Correct Ans - b. Lisch nodules. Learning disabilities and
ADHD can be seen in Legius and NF1, lisch nodules are the most common
clinic sign of NF1 and do not occur in NF2 or Legius, polydactyly is a key
feature of any of these conditions
A 15 year old female is referred to genetics for ataxia. Which of the following
clinical findings would be most helpful for diagnosing her?
a. Oculomotor apraxia
b. If she currently uses a wheelchair
c. If she has ocular telangiectasias
d. When her ataxia began Correct Ans - c. If she has ocular
telangiectasias. Ocular telangiectasias and ataxia are features of AT and help
distinguish this condition from ataxia with oculomotor apraxia
A 1 year old girl is referred to pediatrics clinic due to a skin rash that began as
many blisters and slowly changed. It not appears as hypopigmentation that
follows the lines of blaschko. After taking the family history you find that she
has an 11 year old paternal half sister who presented with the same
symptoms as an infant. She currently has hypo and hyperpigmented skin,
problems with her eyes and a learning disability. What is the most likely
pattern of inheritance in this family?
a. Autosomal Recessive
b. X linked dominant
c. X linked recessive
d. Germline mosaicism Correct Ans - d. Germline mosaicism. Rashes
that begin as blisters, change to appear wart like and end in hypo or
hyperpigmentation that follows blaschko's lines are characteristic of
incontinentia pigmenti syndrome. This condition has XLD inheritance BUT
this condition is lethal in males in the first trimester. The only way for dad to
pass this on is if he is germline mosaic.
Questions & Answers
A young patient (5yrs) presents for the first time to a new dentist with
crowded teeth, making them very hard to clean. In further exploration of the
issue, she learns that the child had delayed eruption of his teeth. The patient's
mother also relays that her pediatrician has several times noted how
prominent the veins of his scalp are and his short stature. However, she thinks
that this is just part of the spectrum seen in their family given that she herself
is quite short and has fair skin, making it easier to see her veins. You speak
with the dentist who isn't sure whether or not to refer the family. You are
most concerned about what mutation:
LMNA G1138A
LMNA G608G
FGFR3 Exon 11 deletion
FGFR3 G608G Correct Ans - LMNA G608G
The current prenatal screening test used in your clinic has a sensitivity of 96%
and a specificity of 89%. In speaking to representatives from the lab, you learn
that they want to adjust their reading of this test by increasing the cutoff
levels. Which of the following effects would you expect to see if this change
was implemented?
i. Increase sensitivity
ii. Increase specificity
iii. Decrease false positives
iv. Decrease false negatives Correct Ans - ii, iii
Which of the following scenarios would MTHFR testing be appropriate?
a. Recurrent pregnancy loss
b. Thrombophilia, in the presence of negative primary thrombophilia testing
c. Open neural tube defect identified on prenatal ultrasound, despite adequate
folic acid intake
d. Patients about to start a methotrexate chemotherapy regimen
e. none of the above Correct Ans - None of the above are reasons that
MTHFR testing should be conducted
Genetic drift is an exception of which of the following assumptions of Hardy
Weinberg:
,a. No mutation
b. No migration
c. Population is infinitely large
d. Random mating Correct Ans - c
For which indication would telehealth service delivery model be
inappropriate?
Breast cancer
Marfan Syndrome
Carrier screening
Cascade testing Correct Ans - Marfan Syndrome (utility of testing
influenced by physical evaluation)
A couple is seen for preconception counseling. The woman's brother has
Gaucher disease, and she has Ashkenazi Jewish ancestry (Gaucher disease
incidence of 1 in 1,000). Before doing any genetic testing, which of the
following is closest to the risk of the couple having an affected child?
1/50
1/100
1/150
1/200 Correct Ans - 1/100
--With incidence of disease in AJ being 1/1000, man's carrier risk is about
1/18
--Woman's risk of being a carrier is 2/3 since her parents are obligate carriers
and she is not affected
-- ⅔ x ½ x 1/18 x ½ = 1/108 = ~1/100
You are meeting a 3 year old little boy in the pediatric genetics clinic. His
parents were referred to the clinic by his astute dentist who mentioned he did
not have as many teeth as expected. On meeting the boy, you also note he has
sparse hair. His parents also tell you he tends to get overheated when he plays
outside. Based on these findings, what is the most likely genetic cause of his
signs and symptoms?
a. Missense mutation in IKBKG
b. Deletion in OCA2
c. Missense mutation in EDA1
*The condition being described is hypohidrotic ectodermal dysplasia which is
most often caused by EDA1 mutations.
,d. Translocation interrupting SPRED1 Correct Ans - c. Missense
mutation in EDA1 *The condition being described is hypohidrotic ectodermal
dysplasia which is most often caused by EDA1 mutations.
A genetic counselor in the ophthalmology clinic is meeting with a family who
have a 12 year old son recently diagnosed with retinitis pigmentosa.
Throughout the appointment, the patient's father makes disparaging remarks
about blindness and his son being handicapped. The genetic counselor finds
herself to be annoyed and angry with the father. The genetic counselor has a
good friend with RP and she can't help but think about him as she talks with
the family. What best describes the behavior and feelings of the genetic
counselor?
a. Transference
b. Countertransference
c. Resistance
d. Resentment Correct Ans - b. Countertransference *The GC is
displaying countertransference as she is transferring her feelings and
experiences with RP in her friend onto the client/the family.
You are meeting with a 30 year old woman to discuss a family history of
reported Alport syndrome. She is hoping to start a family in the near future
and wishes to know her risk to have a child with the condition. After taking
the family history, you notice that only males are affected and there is no
male-male transmission. The patient's maternal uncle is affected. Based on
this family history, what is the highest recurrence risk you would quote for
this patient to have a child with Alport syndrome?
a. 50%
b. 25%
c. 12.5%
d. Less than 1% Correct Ans - c. 12.5%
Alport syndrome can be XLR, AD or AR. However, the most common form and
the form consistent with the pedigree is XLR. This means for the woman's
mom, there is a 50% chance she is a carrier. She has a 50% chance of passing
on that X to the patient. The patient has a 50% chance of passing that onto the
future child. Note, that because it's X linked, females with the condition may or
may not manifest in symptoms.
½ * ½ *½ = ⅛ or 12.5%
, A 12 year old female is referred to genetics after her PCP finds 5 café au lait
spots on physical exam. She also has freckling in her armpits. Which of the
following clinical findings would be most helpful for diagnosing her?
a. Learning disability
b. Lisch nodules
c. ADHD
d. Polydactyly Correct Ans - b. Lisch nodules. Learning disabilities and
ADHD can be seen in Legius and NF1, lisch nodules are the most common
clinic sign of NF1 and do not occur in NF2 or Legius, polydactyly is a key
feature of any of these conditions
A 15 year old female is referred to genetics for ataxia. Which of the following
clinical findings would be most helpful for diagnosing her?
a. Oculomotor apraxia
b. If she currently uses a wheelchair
c. If she has ocular telangiectasias
d. When her ataxia began Correct Ans - c. If she has ocular
telangiectasias. Ocular telangiectasias and ataxia are features of AT and help
distinguish this condition from ataxia with oculomotor apraxia
A 1 year old girl is referred to pediatrics clinic due to a skin rash that began as
many blisters and slowly changed. It not appears as hypopigmentation that
follows the lines of blaschko. After taking the family history you find that she
has an 11 year old paternal half sister who presented with the same
symptoms as an infant. She currently has hypo and hyperpigmented skin,
problems with her eyes and a learning disability. What is the most likely
pattern of inheritance in this family?
a. Autosomal Recessive
b. X linked dominant
c. X linked recessive
d. Germline mosaicism Correct Ans - d. Germline mosaicism. Rashes
that begin as blisters, change to appear wart like and end in hypo or
hyperpigmentation that follows blaschko's lines are characteristic of
incontinentia pigmenti syndrome. This condition has XLD inheritance BUT
this condition is lethal in males in the first trimester. The only way for dad to
pass this on is if he is germline mosaic.
