Title 11 Genetics LMV 5.2.pdf ✅

2 | P a g e [ G e n e t i c s ] © Copyright www.plab1keys.com (Constantly updated for online subscribers) Copyrights @ Plab1Keys.com Autosomal Recessive Autosomal Dominant X-Linked Recessive ◙ If Both Parents are Carriers: • 25% chance of a child to be affected. • 50% chance of a child to be a Carrier. ◙ If one parent is affected and the other parent is carrier → 50% chance of a child to be Affected. And 50% chance of a child to be a Carrier. ◙ If One parent is Affected → 50% chance of a child to be affected. → 25% chance of a Grandchild to be affected. Note: there is no carrier state of autosomal dominant conditions. If a parent does NOT have the gene → 0% he will pass to his/her child. ◙ If Mother is Carrier → 50% chance of a Male child to be affected. ◙ If Father is affected → 0% chance of a Male child to be affected. → 100% chance of a Female child to be carrier. Cystic Fibrosis Huntington’s Disease Duchenne Muscular Dystrophy (DMD) Congenital Adrenal Hyperplasia (21-hydroxylase Deficiency). Neurofibromatosis Haemophilia Thalassemia Autosomal Dominant Polycystic Kidney Disease (ADPKD) G6PD deficiency
3 | P a g e [ G e n e t i c s ] © Copyright www.plab1keys.com (Constantly updated for online subscribers) Copyrights @ Plab1Keys.com Sickle Cell Anemia BRCA gene (breast cancer) Haemochromatosis VWD Hereditary spherocytosis Key 1 Cystic Fibrosis ◙ Understanding the Disease: Cystic Fibrosis (CF) is caused by Autosomal Recessive Mutation in CFTR gene “Cystic Fibrosis Transmembrane Conductance Regulator gene”. This mutation leads to → Increased Viscosity and Thickness of the body’s secretions + High Chloride (Cl- ) in the skin. Think of the symptoms: • Salty skin. • Thick Secretions and mucous accumulates in the lung “Alveoli” making it a good environment for bacterial infection. Thus → Recurrent repetitive cough, with sputum, and chest infections. • Thick secretions, on the long-term, block the pancreatic duct → No pancreatic enzymes are released → ↓ fat and protein Absorption → Failure to
4 | P a g e [ G e n e t i c s ] © Copyright www.plab1keys.com (Constantly updated for online subscribers) Copyrights @ Plab1Keys.com thrive (short and thin child) (+) Fat-containing stool, which is called “Steatorrhea” which presents with bulky, greasy and offensive smell stools. Also, in the long-term, the pancreas will be damaged → DM-type 1. • In Males with CF usually → Congenital Absence of Vas deference → Infertility. • Early after birth, the meconium “the first stool that is passed by a newborn” might not pass due to thickness → Meconium ileus. In short, the common features of Cystic Fibrosis (CF). • Salty-tasting skin, which parents notice when they kiss their child • Frequent coughing, wheezing, or bouts of pneumonia or sinusitis “recurrent chest infections”. • Difficulty breathing that keeps getting worse • Big appetite but poor weight gain (Failure to Thrive). • (Steatorrhea) → Bulky, smelly, greasy bowel movements. • Finger Clubbing. • In the long-run [Complications] → Diabetes, Cirrhosis, Respiratory failure, Bronchiectasis “widened, dilated airways → more susceptible for sputum and mucous collection and infection.