Dysmorphology Flashcards
Genetic vital signs
- Height
- Weight
- Head circumference
Plot on growth chart over time
Microcephaly
Small head —> sign of abnormal brain growth…since usually the head growths with the brain
Eye measurements
Hypotelorism = eyes too close together
Hyper = eyes too far apart
Hallmark sign of fetal alcohol syndrome
Palpebral fissure length
Three things to consider when evaluating
- Ethnic background
- Familial features
- Compare bilateral structure
If a patient has 2+ anomalies
What should be done?
A chromosomal analysis…
A microarray is better to pick up small abnormalities compared to karyotyping
Smith-Lemli-Opitz Syndrome
Defect in cholesterol metabolism in the growing fetus
From a single gene mutation that cause multiple congenital anomalies
Categories of anomalies
- Sequence
- Dysplasia
- Disruption
- Deformation
- Association
‘Sequence’
One anomaly leads to other developmental anomalies
Exs: POTTERS and Prune Belly
POTTERS
P=pulmonary hypoplasia O=oligohydramnios T=twisted skin T=twisted face E=extremity abnormalities R=renal agenesis
**posterior urethral valve blockage can cause this
Usually don’t live past a few days…hard to ventilate
Prune belly syndrome
Results from an enlarged structure in the abdomen that stretches skin…probably ureters
Eventually regresses but skin remains stretched
Symptoms = flat face and club foot deformity
Dysplasia
INTRINSIC developmental abnormality…usually demonstrates in defective cellular org.
Ex: skeletal dysplasia = achondroplasia
Teratogens = FAS
Histology = mis organization of the zones of bone formation
Disruption
Interruption of normal development caused by EXTRINSIC force
So will be asymmetric
ex: amniotic band limb reduction
Deformation
Anomaly caused by EXTRINSIC force (not a loss of structure)
Ex: clubfoot
Any fetal disorder that prevents movement in utero can lead to limb deformation
—> CNS, muscle disease,oligo
Association
An exclusion diagnosis…described by a non-random pattern of associated features
VATER(L) and CHARGE
VATER(L)
V=vertebral A=anal atresia T/E=TEF R=renal/radial L=cardiac and limbs
CHARGE
C=coloboma of iris or retina H=heart A=atresia choanae R=regression of growth G=gentalia E=ears
Multiple hair whirls =
Neural tube defects
Radial ray defects (thumb and index finger)
Greater significance to genetic problems
OMIM
Database you search when trying to diagnose
Always search most rare symptoms presenting
Midline cleft = sign of what
Very rare
Predicts major failure of brain to divide into 2 normal halves (holoprosencephaly)
Severe will die within days
Synophyrs
Unibrow,
Predicts brain defects
Trisomy 13
Has holoprosencephaly
Characteristics of achondroplasia
- Frontal bossing
- Anti-verted nares, flattened nasal bridge
- Trident hand deformity, fingers are grouped in 3
Lysosomal storage disease (general)
Progressive
Head is large relative to thorax
Flat bones
Skeletal dysplasia - progessive after birth
Flat broad ribs
Diabetic embryopathy
Teratogen example
Macrosomia, neural tube defects
Thalidomide embryopathy
Sever limb reduction
Methylmercury embryopathy in Japan
Very neurally fucked
Folate deficiency when pregnant
Moms get folic acid now in pre-natal vitamins
