Autosomal-linked traits

• Autosomes - first 22 homologous pairs of human chromosomes that do not influence the sex of an individual.
• Sex chromosomes - 23rd pair of chromosomes that determine the sex of an individual.
• genotype of an individual with an autosomal dominant trait - AA and Aa (heterozygotes are affected)
• Genotype of an individual without the autosomal dominant trait - aa
• Aa - called a carrier; they carry the recessive allele and can pass it on to offspring, ut they do not express the trait.
• Achondroplasia - mutant allele of gene on chromosome 4 causes deficiency of receptor protein for growth factor. Dwarfism with short limbs; head and trunk sizes are normal.
• Familial hypercholesterolemia - mutant allele of gene on chromosome 19 encodes faulty cholesterol-binding protein. High cholesterol, heart disease.
• Huntington disease - mutant allele of gene on chromosome 4 encodes protein with extra amino acids that causes it to misfold and form clumps in brain cells. Progressive uncontrollable movements and personality changes, beginning in middle age.
• Marfan syndrome - mutant allele of gene on chromosome 15 causes connective tissue disorder. Long limbs, sunken chest, lens dislocation, spindly fingers, weakened aorta.
• Neurofibromatosis (type 1) - mutant allele of gene on chromosome 17 encodes faulty cell signaling protein. Brown sin marks (cafe-au-laitspots), benign tumors beneath skin.
• Polydactyl - multiple genes on multiple chromosome; mechanism is unknown. Extra fingers, toes, or both.
• Albinism - mutant allele of gene on chromosome 11 encodes faulty gene in biochemical pathway required for pigment production. Lack of pigmentation in sin, hair, and eyes.
• Cystic fibrosis - mutant allele of gene on chromosome 7 encode faulty chloride channel protein. Lung infections and congestions, infertility, poor fat digestion, poor weight gain, salty sweat.
• Phenylketonuria (PKU) - mutant allele of gene chromosome 12 cause enzyme deficiency in biochemical pathway that breaks down the amino acid phenylalanine. Buildup of phenylalanine and related compounds causes mental retardation.
• Tay-sachs disease - mutant allele of gene on chromosome 15 causes deficiency of lysosome enzyme. Buildup of byproducts causes nervous system degeneration.
• Camptodactyly - rare genetic abnormality that affects shape and movement of fingers.
• Mitochondrial inheritance - can affect both sex but only passed on by females because all mitochondria of al children come from the mother; can appear in every generation.