Genetics/Dysmorphology

Question 1

Trisomy 21: Down Syndrome

abcd: decreased a/b, cushion defect

Answer 1

Decreased: MSAFP, Estriol
Increased: B-hcg, Inhibin-A

Question 2

Trisomy 21:

Answer 2

• Hearing exam; Echocardiogram; TSH;
• TEF, duodenal atresia association;
• increased risk of ALL, early-onset Alzheimer’s

Question 3

Trisomy 18: Edwards

can’t INHIBIT edward, the boxer

Answer 3

Decreased: MSAFP, Estriol, B-hcg
Normal: Inhibin-A

Question 4

Trisomy 18: Edwards -

‘the boxer”) (low-set ears; microcephaly, clenched hand, rocker bottom feet, hammer toe

Answer 4

• most do not survive first year
• association with omphalocele
• Echo (VSD, ASD, PDA); Renal U/S (polycystic kidneys)

Question 5

Trisomy 13: Patau Syndrome

Patau’s Palate, liP, holoProsencephaly

Answer 5

• Echocardioagram (VSD, ASD, PDA)
• Renal U/S: Polycystic kidneys
• Single umbilical artery

Question 6

Aniridia-Wilms tumor (WAGR)

-deletion on chromosome 11; WT1

Answer 6

Wilms; Anridia: GU anomalies: mental Retardation

work-up: abdominal U/S; CT; BUN/Cr

Question 7

Klinefelters (XXY): 1:500 males

-low IQ, slim with long limbs, gynecomastia

Answer 7

Testosterone levels: hypogonadism, hypogenitalism

Replace testosterone at 11-12 years of age

Question 8

Turner’s syndrome (XO):

sporadic - no genetic or IMA association

Answer 8

Renal U/S: horseshoe kidney, double renal pelvis
Cardiac: Bicuspid aortic valce, coarctation of aorta
Tsh, T4: Primary hypothyroidism
Tx: can give estrogen, GH, steroid replacement

Question 9

Fragile X syndrome: (GCC repeat)

-fragile site on long arm of X

Answer 9

• MCC mental retardation in boys; ADHD association

- large ears, large testes, macrocephaly

Question 10

Neurofibromatosis 1: NF1 chromosome 17 (AD)

Next step: perform opthalmologic exam to look for Iris hamartomas (lisch nodules)

Answer 10

diagnosis >/= 2 of the following (COFFINS) : (1) CALS (2) Optic glioma, (3) Family hx (1st degree relative) (4) Freckling (axillary) (5) Iris hamartomas (Lisch nodules) (6) NFs
(7) Skeletal (bone dysplasia)

Question 11

Prader-Willi: 15q11q13q deletion; paternal

Answer 11

-Decreased life expectancy (due to morbid obesity)

Obesity, MR, binge eating, small genitalia

Question 12

Angelman: 15q11q13q deletion: maternal

Answer 12

• 80% develop epilepsy

Recurrent seizures, MR, inappropriate laughter, absent speech or < 6 words; ataxia, jerky, puppet-like mvmts

Question 13

Robin sequence (Pierre Robin)
Associated with: Fetal Alcohol Syndrome, Edward's 18

Answer 13

-Monitory airway: obstruction possible over first 4 weeks

Mandibular hypoplasia, Cleft palate

Question 14

Beckwith-Wiedemann syndrome

IGF-2 disrupted at 11p15.5

Answer 14

• Increased risk abdominal tumors

- U/S + serum AFP Q 6 months through 6 yrs of age to look for Wilm’s tumor and Hepatoblastoma

Question 15

Beckwith-Wiedemann syndrome

IGF-2 disrupted at 11p15.5

Answer 15

Multiorgan enlargement: macrosomia, macroglossia, pancreatic beta cell hyperplasia (hypoglycemia),
large kidneys, neonatal polycythemia