Miscellaneous Concepts in Genetics😊

Absorption of UV Light:

  • Cause:
    • Due to conjugated double bonds in aromatic rings.

Nucleic Acids:

  • Absorb at 260 nm
  • Due to nitrogenous bases
  • Purines (adenine, guanine) absorb > pyrimidines (cytosine, thymine, uracil)
  • pU → more Uv

Amino Acids & Proteins:

  • Absorb at 280 nm
    • Due to aromatic amino acids
    • Tryptophan shows the maximum absorption
    • Tan - UV

Other Important Absorptions:

  • NAD & NADP → absorb at 340 nm
  • Porphyrins → absorb at 400 nm (called the Soret Band) → Blue
  • Phototherapy → 480 nm

Genetic Syndromes and Associated Tumors

Syndrome
Gene(s)
Chromosome(s)
Inheritance
Tumor Associations
Ataxia telangiectasia
ATM
11q22-q23
AR
Breast
Bloom syndrome
BLM
15q26.1
AR
Several types
Cowden syndrome
PTEN
10q23
AD
Breast, thyroid
Autoimmune lymphoproliferative syndrome
FAS/FASL
10q24 1q23
AD
Lymphomas
Familial adenomatous polyposis
APC
5q21
AD
Intestinal adenoma, colorectal
Familial melanoma 1
p16INK4
9p21
AD
Melanoma, pancreatic
Familial Wilms' tumor
WT1
11p13
AD
Kidney (pediatric)
Hereditary breast/ovarian cancer
BRCA1/BRCA2
17q21 13q12.3
AD
Breast, ovarian, colon, prostate
Hereditary diffuse gastric cancer
CDH1
16q22
AD
Stomach
Hereditary multiple exostoses
EXT1/EXT2
8q24 11p11-12
AD
Exostoses, chondrosarcoma
Hereditary prostate cancer
HPC1
1q24-25
AD
Prostate
Hereditary retinoblastoma
RB1
13q14.2
AD
Retinoblastoma, osteosarcoma
Hereditary nonpolyposis colon cancer (HNPCC)
MSH2/MLH1/MSH6/PMS2
2p16 3p21 2p16 7p22
AD
Colon, endometrial, ovarian, stomach, small bowel, ureter carcinoma
Hereditary papillary renal carcinoma
MET
7q31
AD
Papillary kidney
Juvenile polyposis
SMAD4
18q21
AD
Gastrointestinal, pancreatic
Li-Fraumeni
TP53
17p13.1
AD
Sarcoma, breast
Multiple endocrine neoplasia type 1
MEN1
11q13
AD
Parathyroid, endocrine, pancreas, pituitary
Multiple endocrine neoplasia type 2a
RET
10q11.2
AD
Medullary thyroid carcinoma, pheochromocytoma
Neurofibromatosis type 1
NF1
17q11.2
AD
Neurofibroma, neurofibrosarcoma, brain
Neurofibromatosis type 2
NF2
22q12.2
AD
Vestibular schwannoma, meningioma, spine
Nevoid basal cell carcinoma syndrome (Gorlin's syndrome)
PTCH
9q22.3
AD
Basal cell carcinoma, medulloblastoma, jaw cysts
Tuberous sclerosis
TSC1/TSC2
9q34 16p13.3
AD
Angiomyolipoma, renal angiomyolipoma
von Hippel-Lindau
VHL
3p25-26
AD
Kidney, cerebellum, pheochromocytoma
Multiple endocrine neoplasia type 4
CDK1B
Not specified
Not specified
Parathyroid, pituitary, gonadal (ovarian/testicular), renal/adrenal tumors (Note: Information about MEN 4 is from a different source but is relevant to genetic syndromes and tumors).