Groups of anomalies

21 important questions on Groups of anomalies

What kind of defect pattern is a sequence?


Single known or presumed structural defect or mechanical factor leading to a cascade of secondary anomalies (domino effect)

Explain the Pierre Robin sequence.


Jaw constraint → micrognathia (small lower jaw) → glossoptosis (tongue too posteriorly sitting) → U–shaped cleft palate

Can the pierre robin sequence be corrected?

It can be corrected surgically to reduce its functional implications
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Can the potter sequence be treated?

No, it is lethal in 100% of cases

What kind of defect pattern is a syndrome?

Multiple defects (major or minor) that occur together in a recognizable way/pattern.

How are the defects in a syndrome related?

Defects in a syndrome are pathogenetically related

What defect patterns does a syndrome not fall under?

Excludes patterns known to represent a single sequence or a polytopic field defect

What are the symptoms of down syndrome (trisomy 21)?


- Short neck, with excess skin at the back of the neck
- Flattened facial profile and nose
- Small head, ears, and mouth
- Upward slanting eyes
- Wide, short hands with short fingers
- A single, deep, crease across the palm of the hand (single palmar crease, also a normal variation)
- A deep groove between the first and second toes
- Intellectual deficiencies

What is the cause of fetal alcohol syndrome?

Caused by teratogen, when the pregnant mother drinks alcohol

What are the symptoms of fetal alcohol syndrome?


1. Facial features (small eye openings, smooth philtrum, thin upper lip)
- higher teratogen/alcohol exposure = more pronounced facial features
2. Neurological features/intellectual disability
3. Growth deficiency

What kind of defect pattern is a polytopic field defect?

Multiple anomalies in the same developmental region that arises from the disturbance of a single developmental field

What is a single developmental field?

Region or part of an embryo that responds as a unit to embryonic interactions

How can a sequence and a polytopic field defect be differentiated?

The cause of the pattern of defects must be identified to indicate whether that pattern is a sequence or a polytopic field

What is DiGeorge syndrome?

Deletion of chromosome 22q11.2 that affects 3rd and 4th pharyngeal arch

What are the defects characterised in DiGeorge syndrome?

Truncus arteriosus
Thymic and parathyroid hypoplasia
Facial dysmorphism
Cleft palate

What is Holoprosencephaly spectrum?


Failure/abnormal development of forebrain, which affects development of the face

What kind of pattern of defect is association?


Non-random combination of anomalies which occur together more frequently than by chance alone, but the origin is (still) unknown

How can association be classified as a syndrome instead?

Once the cause of that pattern of defect is identified, that association can be classified as a syndrome instead.

What are the other patterns of defects that an association does not fall under the same category of?

Association excludes polytopic field defect, sequence, or syndrome

How many cases of individuals with that pattern of defect needs to be identified for it to be classified as an association?

Need to be present in 2 or more individuals with statistically related symptoms

What are the defects that follow VACTERL association?


Vertebral defects
Anal atresia
Cardiac defects
Tracheo-esophageal fistula
Renal defects
Limb defects
All defects arise from the mesoderm.

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