Dysmorphology Flashcards
It’s important to use objective measurement. What are some genetic vital signs?
Height, weight, head circumference, growth/stature, microcephaly
Ex) Obesity for Prader-Wili syndrome
Ex) Palpebral fissure length for Fetal Alcohol Syndrome
Other considerations when assessing a patient other than objective measurements
Ethnic background
Familial features
Bilateral structures
Progression
Consider all structures!
Use the ___ anomaly in searching for a diagnosis
rarest
Most structural anomalies are isolated/multiple
Isolated and sporadic (no known cause)
Ex) Cleft lip, cong heart malformation
Intrinsic abnormalities
Abnormalities in the genes or chromosomes OR changes at the cellular level that may be caused by teratogens.
(Instruction manual has mistakes or mistakes were put in and things grow wrong from onset)
Extrinsic abnormalities
Outside factors cause a malformation
Ex) Too little room, amniotic bands, etc
Sequence
One anomaly (intrinsic or extrinsic cause) leads to other developmental anomalies
Ex) POTTER Syndrome: kidney fluid isn’t released –> no amniotic fluids –> variety of symptoms
Dysplasia
Malformations from
- Intrinsic forces (single gene defects) OR
- Abnormalities in cellular organization due to things like teratogens
Ex) Thalidomide in fetal alcohol syndrome causes limb dysplasia
Disruptions
There is normal development of tissues but it gets destroyed due to extrinsic effects
*destruction of tissue*
Ex) Amniotic bands from intra-uteric infections can cause amputation/limb reductions
Deformations
Extrinsic effects leading to abnormal development
Especially common in the 2nd trimester
Ex) Clubfoot can result from there not being enough space or normal nerve development
Ex) CNS malformations leading to severe arthrogryposes due to decreased fetal movement
Association
Exclusion diagnosis described by a group of anomalies that occur together more often than expected by chance, but with no known etiology
Ex) VATER/VACTERL and CHARGE
Syndrome
Recognizable pattern of anomalies due to a single known or presumed etiology
-Can be caused by chromosomal abnormalities, contiguous gene deletions, single gene defects or teratogens
Thalidomide causes
Limb dysplasia
Of the multiple anomalies, only 50% have known etiology. Of those with known etiology, the majority are caused by _____, thus ______.
Chromosomal abnormalities, so chromosomal analysis should always be the first test done
VATER and CHARGE are both associations. Which has more intellectual development?
VATER
