Explain the inheritance pattern of Congenital Adrenal Hyperplasia (CAH), assuming it's an autosomal recessive condition.

Step 1: Define alleles. Let 'A' represent the dominant allele for normal adrenaline production (no CAH). Let 'a' represent the recessive allele for CAH. Step 2: Determine parental genotypes. Since CAH is a recessive condition, a person must have two recessive alleles (aa) to have the condition. Parents who do not have CAH but can have a child with CAH must both be heterozygous carriers. This means each parent has one dominant allele and one recessive allele. Parent 1 genotype: Aa (Normal, carrier) Parent 2 genotype: Aa (Normal, carrier) Step 3: Determine parental gametes. Each parent will produce two types of gametes: Parent 1 gametes: A, a Parent 2 gametes: A, a Step 4: Construct a Punnett square. The Punnett square shows the possible combinations of alleles in their offspring. |c|c|c| Gametes & A & a \\ A & AA & Aa \\ a & Aa & aa \\ Step 5: Explain offspring genotypes and phenotypes. From the Punnett square, the possible genotypes for the offspring are: • AA: 25% chance (Normal, non-carrier) • Aa: 50% chance (Normal, carrier) • aa: 25% chance (Has CAH) Explanation: When both parents are heterozygous carriers (Aa), there is a 25% probability that their child will inherit the recessive allele (a) from each parent, resulting in the genotype aa. A child with the genotype aa will express the recessive condition, CAH, even though neither parent has the condition themselves. Here is the genetic diagram: Parents' phenotypes: Normal (no CAH) × Normal (no CAH) Parents' genotypes: Aa × Aa Parents' gametes: A, a × A, a Punnett Square: |c|c|c| Gametes & A & a \\ A & AA & Aa \\ a & Aa & aa \\ Offspring genotypes: 1 AA : 2 Aa : 1 aa Offspring phenotypes: 3 Normal (no CAH) : 1 CAH This diagram shows that there is a 1 in 4 chance for parents who are both carriers (Aa) to have a child with CAH (aa). Send me the next one 📸