4 Answer the following about the above pedigree a. What is the sex of I 1? ___________________b. How many children does IV 2 have? ___________c. How many children of IV 12 have cancer? ____________d. List all of the males who have polyps (carriers) __________
6 Lethal genetic disorder caused by rare autosomal dominant allele Huntington’s DiseaseLethal genetic disorder caused by rare autosomal dominant alleleNervous system disintegrates causing loss of control of limbs and mental deterioration.
7 Huntington’s diseaseSince onset occurs between ages 30 and 50, this defect can be transmitted to new generations before the parent knows that he is a carrier.
8 Genetic testing can determine if a person is a carrier. Huntington’sGenetic testing can determine if a person is a carrier.Carriers will get disease because allele is dominant.
10 Recessive Autosomal Heredity Genetic disorders caused by recessive alleles.Most genetic disorders are caused by this type of allele.Cystic fibrosis, sickle -cell anemia, Tay - Sachs disease, Phenylketonuria (PKU).
11 Cystic FibrosisMost common lethal genetic disorder in white Americans.Characterized by thick mucus in lungs and digestive tract.Food is not digested properlyBreathing is difficult - frequent lung infections
12 Tay- SachsAbsence of enzyme that breaks down a lipid that is produced and stored in the central nervous system. Lipid builds up in brain membranesCommon in Eastern European Jews and Pennsylvania Dutch.
13 Symptoms of Tay-Sachs Disease BlindnessProgressive loss of movementMental deteriorationDeath by age 5.See pg 312 for pedigree
14 Phenylketonuria (PKU) Most common in people of Norwegian and Swedish descent.Caused by absence of enzyme that converts phenylalanine to tyrosine (amino acids).
15 Symptoms of PKU New born appears normal. Once baby starts drinking milk, which is high in phenylalanine, damage occurs
16 SymptomsBuild up in phenylalanine causes severe central nervous system damage resulting in mental retardation.
17 Treatment of PKU All newborns are tested for PKU. Changes in diet can prevent damage.
18 New Problems With PKUIf a homozygous recessive female becomes pregnant, high levels of phenylalanine in her blood can damage baby.