Genetics Review - Final XLS in CSV form - Sheet1 Flashcards
What is the most common trisomy in abortuses?
Trisomy 16
What aneuploidy is seen with holoprosencephaly and midline facial defects?
Trisomy 13
Triple screen shows a normal AFP, normal HCG and a low E3. What condition is this associated with?
X-linked icthyoses and SLOS
What is the most common cause of CAH?
21 alpha hydroxylase deficiency
How do you treat the fetus is the mother has CAH?
Dexamthasone, starting at 7-8 weeks. To prevent virilization of female fetus
What karyotype is suggestive of uniparental disomy?
From any trisomy as a trisomic rescue
( i.e you have trisomy 13 on CVS, the fetus tries to save itself by losing chromosome 13 but loses the wrong one and gets a uniparental disomy)
Which maternal karyotype has the highest risk of Down syndrome?
21:21 Translocation (100% of live babies are T21, but of total gametes 50% would be monosomy 21)
What is the most common finding with Trisomy 21 on sono at 18-20 weeks?
Nuchal Fold
What is the most common finding of a term infant with Down syndrome?
- Simian crease
- Hypotonia
- LBW <2500gm
Hypotonia
Most common outcome if NT is increased?
Normal
What syndrome has coarctation of the aorta?
Turners
What condition with CF carries a poor prognosis?
Cor Pulmonale
Which syndrome has absent radius, polyhydramnios and hydronephrosis?
Thrombocytopenia absent radius (TAR) Syndrome
- can have kidney, heart and thrombocytopenia with absent radius
- both radii are missing but thumbs are present
Which is not related to non-disjunction in the mother?
- Turners
- Klienfelters
- XXX
Turners
The single X is maternal in origin in 70% of cases. Paternal is lost
Anomaly of what system is most commonly seen with diaphragmatic hernia ?
Cardiac
What is the risk of Down syndrome with a prior afected child?
1% or the age related risk, whichever is higher
Which condition is most likely associated with aneuploidy?
- Cardiac
- Omphalocele
Omphalocele
What pattern of inheritance is passed through maternal only?
Mitochondrial
Which maternal cardiac lesion is associated with the greatest fetal risk of transmission?
- AS
- MS
- VSD
- TOF
Aortic stenosis (15-18% risk of fetal transmission)
IHSS: 50%
Coarctation: 14%
Which condition is most likely to transmit to the fetus?
- ASD
- VSD
- Coarctation
- TOF
Coarctation
45XX, der(13,21)(q10q10) is associated with what?
Normal.
This is a balanced translocation on 13q;21q
What mechanisms result in uniparental disomy?
2 chromosomes inherited from one parent, trisomic rescue
Ex: Beckwith, Angelman, Prader-Willi
Amniotic fluid acetylcholinesterase is least helpful with what condition?
- Omphalocele
- Gastroschisis
- Congenital nephrosis
- Anencephaly
Congenital nephrosis
What should you do if cord insertion at 8 weeks is abnormal?
Repeat ultrasound because of physiologic herniation
Which situation is most likely to result in a fetus having T21?
- mom 45XX rob(14;21)
- dad 45XX rob(14:21)
Mom 10-15%
Dad: <5%
Which of the following is not associated with AMA? T21 T13 T18 45XO
45 XO
Which of the following is associated with coarctation of the aorta?
45 XO
As a class, what is the most common etiology for fetal malformations?
Genetic
Which karyotype is the result of a uniparental disomy?
A Trisomy - results in UPD from trisomic rescue
Fetus has cleft lip/palate, VSD, holoprosencephay. What is the most likely diagnosis?
T13
What is the most reliable ultrasound criteria for dating?
Cerebellum
Foot length
Which disease is AD and is associated with telengiectasia, ataxia, thrombocytopenia?
Osler Weber Rendu
Elevated AF Acetylcholinesterase is NOT associated with which of the following? Apalsia Cutis Omphalocele Anencephaly Encephalocele Congenital nephrosis
Congenital nephrosis
What are the two AF molecules elevated with aplasia cutis?
AFP and Acetylcholinesterase
- elevated with all open wall defects
Choroid plexus cysts are most commonly associated with which aneuploidy?
- T21
- T13
- T18
T18
30-50% of T18 have CPC
Multiple intraabdominal echogenecities are least associated with which condition?
- CF
- Aneuploidy
- Toro
- Parvo
- Meconium peritonitis
Parvo
Which of the following syndromes is caused by uniparental disomy?
Angelman
Beckwith
Prader- Willi
CVS cannot diagnose which conditions?
NTD
Fragile X
Early amniocentesis at 14 weeks is associated with?
It is associated with: fetal loss, club foot, failed procedure, PROM
What is the sensitivity of Quad screen in detecting T21 in a patient <35 years?
75%
Patient has a fetus with T21, what is the risk of recurrence?
1%, or age related risk whichever is higher
Fragile X inheritance is associated with what number of repeats? What are the repeat letters?
> 200
What would be the pattern on QUAD screen of a fetus with Down syndrome?
High: HCG & Inhibin
Low: Estriol, AFP
Which anomaly is associated with the highest risk of aneuploidy?
- Omphalocele
- Cardiac defects
- Gastroschisis
Omphalocele
What is the most common reason for birth defects?
Genetic
What is the most common genetic cause of mental retardation?
Fragile X
Karyotype shows 45XX t(14;21). What is the phenotype?
Normal
Balanced translocation
Holoprosencephaly is most commonly associated with which of the following chromosomal abnormalities?
Trisomy 13
Ultrasound findings would increase the risk of Down syndrome, except: Duodenal atresia Increased Nuchal Fold Cardiac anomaly Short femur Sandal gap
Sandal gap
What is the most common non-infectious, non-genetic cause of MR?
Fetal alcohol syndrome
All of the following US findings would be present in a fetus with a neural tube defect EXCEPT: Small cisterna Scalloped cerebellum Incavatated cranium Ventrculomegaly Increased BPD
Increased BPD
What is the best treatment for in utero CAH?
Dexamthasone, starting at 7-8 weeks. To prevent virilization of female fetus
Which chromosomal abnormality is not increased in offspring of AMA females?
Turner Syndrome
Which malfomation has the greatest risk of underlying aneuploidy? CHD Gastroschesis Omphalocele Clubbed foot
Omphalocele
What causes virilization of a female fetus? Luteoma of pregnancy Cystadenoma Prolactinoma OCPs
Luteoma of pregnancy
What is associated with fetal abdominal calcifications?
CMV
Which syndrome is associated with fetal thrombocytopenia?
- Absent radius
- Gestational thrombocytopenia
- Erythroblastosis fetalis
- Bernard Soulier syndrome
TAR Syndrome - Thrombocytopenia, Abset radius syndrome (but thumb present)
Which can also pretsent with Kidney or Heart issues
What is associated with pancytopneia and absent radius?
Fanconi’s anemia
Gaucher’s disease is a disorder of:
Glucocerebrosidase
What type of inheritence is associated wuth Leber’s optic atrophy?
Mitochondrial
Which disorder is associated with UPD? Cri du chat Williams Prader Willi Hydantoin
Prader Willi
All of the following diseases are associated with DNA repeats except: Fragile X Huntington's CF Myotonic Dystrophy
Cystic Fibrosis Repeats: FraGile X (CGG) Huntingtons (CAG) MyoTonic Dystrophy (CTG)
A normal woman has a homozygoous 21/21 translocation. What percent of her offspring will have Down syndrome?
100%
A normal woman has a homozygoous 21/21 translocation. What percent of her conceptuses will have monosomy 21?
50%
What percent of omphaloceles will have a chromosomal aneuploidy?
30 - 40%
Duodenal atresia is associated with what other findings?
Polyhydramnios
Aneuploidy with duodenum abnormality?
T21 in 30%
What are the causes of non-immune hydrops?
Idiopathic Cardiovascular Chromosomal - Turners Infections CCAM, Sacrococcygeal teratoma
Increased nuchal fold is associated the most with what aneploidy?
T21
NTD is associated with what intercranial findings?
Banana sign
Lemon sign
Ventriculomegaly
Small cisterna magna
What cardiac anomaly cannot be identified with 4 chamber view ?
TGA
Coarctation
VSD
What is the best megahertz to assess abdominal circumference at 20 weeks?
3.5 mHz
What are the ultrasound findings of holoprosencephaly?
Single ventricle
Absent corpus callosum
Doppler studies reflect what parameter?
Velocity
What is the preferred mode of delivery for Omphalocele?
Vaginal unless >5cm or liver is out
What is the management hydrocephaly?
US, infectious and genetic workup
Which of the following is the LEAST likely diagnosis with micromelia and hypocalcification of the skull are seen or ultrasound? OI Achondrogenesis Hypophosphatemia Thanatophoric dysplasia
Thanatophoric dysplasia
What is the most common associated anomaly with single umbilical artery?
Cardiac defects
Mom presents with acute chest syndrome due to HbSS. Dad not tested. But carrier rate is 1/12. What is the risk of an affected fetus?
.1/24
