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Radiology
Trisomy 13
Built from Obstetric Imaging
What’s inside
8 sections · 74 slides
Overview
- What you will learn here
An extra chromosome 13
What the disorder is, how it arises, and how common it is
- Start with the chromosomes
- Trisomy 13 in one look
- Chromosome count in Patau syndrome
- How the spare chromosome gets there
- Chromosomes failing to separate in meiosis
- Two routes to the same result
- Why so many organs are affected
- From spare chromosome to abnormal face
- Advanced maternal age is the known risk factor
- 0.5–2.0
- Who it affects
What happens to the pregnancy and the baby
Losses before birth, findings at birth, and survival afterwards
- The natural course, stage by stage
- Most are found before birth
- What the newborn looks like: head and face
- What the newborn looks like: the rest of the body
- Undivided forebrain in a fetal brain specimen
- Holoprosencephaly, explained
- Survival after birth
- The heart drives the outcome
- Why heart surgery stays controversial
Seeing it on ultrasound
The primary imaging test, and what it shows in each trimester
- Ultrasound is the main test
- >90%
- What the detection studies found
- How screening has changed
- First-trimester ultrasound findings
- Widened fluid space behind the fetal neck
- What nuchal translucency actually is
- Blood screening does not replace the scan
- The ultrasound clues, gathered
- The second trimester: two dominant groups
- Heart defects seen in the fetus
- The face on the anatomy scan
- Split in the fetal upper lip
- Hands and feet
- Extra digit on the fetal hand
- Six-digit hand on radiograph
- Kidneys and the abdominal wall
- Bowel bulging at the cord insertion
- Why an omphalocele changes everything
- Growth restriction
When MRI is added
A second-line look, mainly at the brain
- Fetal MRI as the second look
Conditions that look the same
Five differentials that share the brain, face and limb findings
- Why the differential matters
- Isolated holoprosencephaly
- Pseudo-trisomy 13
- How pseudo-trisomy 13 is defined
- Mosaic trisomy 13
- Smith-Lemli-Opitz syndrome
- Smith-Lemli-Opitz: limbs and spectrum
- Meckel-Gruber syndrome
- The look-alikes at a glance
Confirming it and caring for the family
From a suspicious scan to a definitive answer and a care plan
- From suspicion to answer
- Routes for testing during pregnancy
- Offering the definitive test
- Genetic counselling belongs here
- There is no treatment before birth
- Decisions around labour
- Planning care after delivery
- When the karyotype confirms it
- Problems in infants who survive
- What surgery can and cannot buy
Bringing it together
The referral message, the key points, and the sources
- What the referring clinician needs to know
- The message to give the family
- Key points
- “
- Suggested readings
- References
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- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition