Genetic Syndromes

Trissomy 21

Down's Syndrome

overall 1:700; rises with maternal age (5% by 45)

Cardiac defects ==> 40% AVSD

1% risk of leukemia

Hypothyroidism

Low IQ / developmental delay

Trissomy 18

Edwards Syndrome

1:6000;

microcephaly (proeminent occipital), microphtalmia, coloboma of iris

Cleft lip/palate; micrognathia

Cardiac defects ==> 60%

Profound MR

90% die in 1st year

Trissomy 13

Patau Syndrome

1:10.000

Microcephaly (sloping forehead), microphtalmia

Midline anomalies, cleft lip/palate

Severe IUGR, Proound MR

90% die in 1st year

DiGeorge Syndrome

Microdeletions of 22q11

2nd most common genetic diagnosis

CATCH 22

Cyanotic CHD

Anomalies

Thymic hypoplasia

Cognitive impairment

Hypoparathyroidism

22q11 microdeletion

Prader-Willi

Lack of paternal 15q11

H30

Hypotonia

Hypogonadism

Obesity (obssesive hyperphagia)

Developmental delay

Angelman

Lack of maternally 15q11

Severe MR, seizures, tremoulesness

Uncrontrollable laughter

Noonan Syndrome

Autossomic dominant inheritance with variable expression

Phenotype similar to Turner's

MR in 25%

Right-sided CHD ==> pulmonary sternosis

Delayed puberty

Turner Syndrome

45,X0

mild MR-normal IQ

streak ovaries

Cardiac defects

bicuspid aortic valve, CoAo

Tx:

GH for short stature

Estrogen in adolescence

Klinefelter

47, XXY

1:1000; increases with maternal age

Tall, long limbs, slim, underweight

hypogonadism ==> gynecomastia, lack facial hair

behavioural/psychiatric disorders

Tx: testosterone in adolescence

Fragile X Syndrome

X-linked; anticipation disorder

Most common cause of MR in boys

Proeminent jaw, forehead and nasal bridge; long, thin face

High-arched palate

Macroorchidism

Mild-moderate MR; ADHD and/or autism