Chromosomal Abnormalities

Question 1

Down Syndrome

Answer 1

Trisomy 21
95% meiotic nondisjunction due to advanced maternal age, 4% translocation, 1% mosaics
Mental retardation, cardiac septal defects, leukemia, Alzheimer’s, & Hirschsprung’s (missing nerves in colon)

Question 2

DiGeorge & Velocardiofacial Syndrome

Answer 2

22q11.2 deletion
Congenital heart disease (tetralogy of fallot)
Cleft palate
Thymic & & parathyroid hypoplasia -> impaired T cell immunity & hypocalcemia
Developmental delay, schizophrenia, bipolar disorder

Question 3

Klinefelter Syndrome

Answer 3

47XXY due to nondisjunction
Male hypogonadism
Testicular atrophy, low testosterone, high gonadotropin, infertility, gynecomastia, reduced facial hair, breast cancer, extragonadal germ cell tumors, lupus

Question 4

Turner Syndrome

Answer 4

45X
Primary hypogonadism, primary amenorrhea, short stature, webbed neck, lymphatic malformation, congenital heart disease, horseshoe kidney, hypothyroidism

Question 5

Patau Syndrome

Answer 5

Trisomy 13
Cleft lip
Polydactyly

Question 6

Edward Syndrome

Answer 6

Trisomy 18
Micrognathia (undersized jaw)
Overlapping fingers