Learning Objective: By the end of this session, the learner will be able to: Identify key genetic disorders associated with specific human chromosomes and correlate them with common clinical presentations and inheritance patterns.
Summary Table: Genetic Disorders by Chromosome
| Chromosome | Selected Examples |
|---|---|
| 3 | von Hippel–Lindau disease, renal cell carcinoma |
| 4 | ADPKD (PKD2), achondroplasia, Huntington disease |
| 5 | Cri-du-chat syndrome, familial adenomatous polyposis |
| 6 | Hemochromatosis (HFE) |
| 7 | Williams syndrome, cystic fibrosis |
| 9 | Friedreich ataxia, tuberous sclerosis (TSC1) |
| 11 | Wilms tumor, β-globin gene defects (eg, sickle cell disease, β-thalassemia), MEN1 |
| 13 | Patau syndrome, Wilson disease, retinoblastoma (RB1), BRCA2 |
| 15 | Prader–Willi syndrome, Angelman syndrome, Marfan syndrome |
| 16 | ADPKD (PKD1), α-globin gene defects (eg, α-thalassemia), tuberous sclerosis (TSC2) |
| 17 | Neurofibromatosis type 1, BRCA1, TP53 (Li–Fraumeni syndrome) |
| 18 | Edwards syndrome |
| 21 | Down syndrome |
| 22 | Neurofibromatosis type 2, DiGeorge syndrome (22q11 deletion) |
| X | Fragile X syndrome, Turner syndrome (XO), X-linked agammaglobulinemia (Bruton), Klinefelter syndrome (XXY) |
Key Concepts
- Disorders can cluster by chromosome, helping in diagnostic recall during Step 1 genetics questions.
- Autosomal dominant conditions often involve structural proteins or regulatory genes (e.g., Marfan, NF1).
- Autosomal recessive and X-linked diseases often involve enzyme deficiencies (e.g., CF, G6PD).
- Chromosomal deletions or duplications (e.g., 22q11 deletion) cause syndromic patterns with multiple organ systems affected.
