SECTION 3: Genetic Disorders, CHROMOSOMAL

Name examples of autosomal dominant disorders.

Marfan syndrome
Huntington’s disease
Familial hypercholesterolemia
Neurofibromatosis type I

Name examples of autosomal recessive disorders.

Cystic fibrosis
Sickle cell anemia
Phenylketonuria (PKU)
Tay-Sachs disease

Name examples of X-linked recessive disorders.

Duchenne muscular dystrophy
Hemophilia A and B
G6PD deficiency
Color blindness

Name examples of X-linked dominant disorders.

Rett syndrome
Fragile X syndrome
Vitamin D-resistant rickets

What is a chromosomal abnormality?

A change in the normal number or structure of chromosomes, which can cause disease or developmental issues.

What are the types of chromosomal abnormalities?

Numerical: Abnormal number (e.g., trisomy, monosomy)
Structural: Deletions, duplications, translocations, inversions

Describe Down syndrome.

Trisomy 21
Intellectual disability, flat facial profile, hypotonia
Risk increases with maternal age
Diagnosed via karyotyping or prenatal screening

Describe Turner syndrome.

• Monosomy X (45,X)

• Affects females

• Short stature, webbed neck, infertility

• No secondary sexual characteristics

Describe Klinefelter syndrome.

• 47,XXY karyotype

• Affects males

• Small testes, gynecomastia, infertility

• Often diagnosed during puberty