Genetics Morphology Terminology Am J Gen

Cranium

Brachycephaly - short AP head diameter

(measure inter-parietal bns distance / distance bn glabella and occiput)

Dolichocephaly - long AP head diameter

( " " " "...)

Scaphocephaly - a subtype w pointed ant and post aspects, boat shaped head

Macrocephaly - enlarged head circ >97th %ile

Microcephaly - reduced head circ <3rd %ile

Flat Occiput - reduced occiput convexity

Prominent Occiput - increased occiput convexity

Plagiocephaly - asymmetric head shape- usually bc of unilat occipital flattening w ipsilat frontal prominence --> rhomboid cranial shape

Cloverleaf Skull - trilobar skull if viewed fr front or behind

Trigoncephaly - wedged-shaped, triangle shaped - apex at forehead

Turricephaly - tall head relative to width & length

Scalp Hair

Frontal Upsweep of Hair - aka Cowlick (no longer used) - upward and/or sideward ant hair growth

Abnormal Hair Whorl Number - >2 clockwise hair whorls; most ppl hae one clockwise hair whorls, at a single pt on scalp, lat to midline but near the vertex of the skull. %5 of ppl have 2 whorls. 10% of ppl have counterclockwise whorls.

Double Crown - Abnormal position of hair whorl- growth from a single pt on scalp in any other location than above; can be parietal, vertex, eccentric, nor abNl # of whorls

Frontal Balding - no hair at ant midline +/- parietal areas

High Anterior Hairline - >2 standard deviations above mean distance bn hairline and glabella

Low Anterior Hairline - >2 standard dev below ...

Low Posterior Hairline - often seen in later childhood, as neck lengthens in pts w who have redundant neck skin

Sparse Scalp Hair - decreased number of hairs

Widow's peak - frontal hairline has bilat arcs to form a low pt in the forehead midline

-might need to pull hair back to see it

Face

Broad Face - upper and lower face width >2SD above mean

Course Face - no fine/sharp appearance of brows, nose, lips, mouth, chin - bc of rounded and heavy features or thickened skin +/- thickening of subQ and bony tissues

Expressionless Face - reduced facial movement --> reduced crease formation

Flat Face - absence of concavity or convexity of the face when viewed in profile

-imagine a line connecting glabella to ant most part of mandible touches the top of the philtrum where it meets teh base of the columella. The glabella is the most prominent pt of the frontal bn above the root of the nose, the sup philtrum is ant to this line in a convex face and post to the line in a concave face

Long Face - height >2SD above mean

Short Face - height >2SD below mean

Narrow Face - upper and lower face >2SD below mean

Round Face - more circular than usual when viewed fr front

Square Face - in frontal vivews, face has a broad upper face/cranium and lower face/mandible--> square

-ddx broad jaw- jaw is broader than forehead

Triangular Face - triangle from frontal view, w broad head at temples, narrows to chin...

Forehead

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Genetic Testing Review

Amniocentesis

-drawn at___ for___

Chorionic Villus Sampling

-drawn at __ for ___

FISH- fluorescence in situ hybridization - localize a cloned segment of DNA on a chromosome by binding complementary DNA and then visualizing it's location with flurorescence microscopy

Microarray- grid of multiple DNA fragments fixed to a glass slide for hybridization to test sequence

Comparitive genomic hybridization - take a control and reference DNA sample, and competitively hybridize them to a reference sequence--> detects deletions or duplications

Complex Segregration Analysis - analyze the pattern of genetic transmission by testing various models to explain the dataset, and establish a best fit model (of transmission)