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Abnormal Karyotype
Ultrasound Fetal Abnormal Karyotype Terms
Term | Definition |
---|---|
abnormal nuchal translucency | >3mm associated with chromosomal abnormality, >4mm = even higher risk |
Trisomy 21 | Down's Syndrome |
Trisomy 21 | most common |
Trisomy 21 | extra chromosome #21 |
Trisomy 21 | physical features include: - brachiocephalic head - nuchal fold measurement >6mm - flattened/absent nasal bone - protruding tongue |
Trisomy 21 | sonographically: - nuchal translucency >3mm - nuchal fold >6mm - cardiac defects - duodenal atresia - shortened extremities - clinodactyly of 5th finger - echogenic foci in heart - short femur for GA |
Trisomy 18 | Edward's Syndrome |
Trisomy 18 | extra chromosome #18 |
Trisomy 18 | poor prognosis: lethal |
Trisomy 18 | sonographically: - small chin (micrognathia) - low set ears - strawberry head - clinched hands - rocker bottom feet - IUGR - polyhydramnios - cleft lip/palate - single umbilical artery |
Trisomy 13 | plateau syndrome |
Trisomy 13 | most severe: lethal |
Trisomy 13 | extra chromosome #13 |
Trisomy 13 | most miscarry early |
Trisomy 13 | sonographically: - holoprosencephaly - hypotelorism - micrognathia - polydactyly - echogenic kidneys - cleft lip/palate - cranial anomalies |
Triploidy | 3 sets of chromosomes |
Triploidy | 69 chromosomes |
Triploidy | most abort 1st trimester |
Triploidy | 1 egg is fertilized by 2 sperm |
Triploidy | partial molar pregnancies |
Turner's Syndrome | 45X |
Turner's Syndrome | sex chromosome is absent |
Turner's Syndrome | only occurs in females |
Turner's Syndrome | sonographically: - cystic hygroma (most common association) - cardiac defects - hydrops |
Turner's Syndrome | physically: - short stature - mental retardation - not diagnosed until puberty (lack of menses) |
Pierre Robin Syndrome | sonographically: - micrognathia - glossoptosis (abnormal downward tongue) - cleft palate (creates difficulty in eating) |