inheritance human bio y11

Symptoms appear after 40

Occasional involuntary flailing movements of the arms and legs

Difficulty making voluntary movements of limbs

Writhing movements of hands, head, trunk and feet

dementia

Genetic screening now available for people with parent who either has Huntington's disease or died from it

Blood from close relatives are collected and analysed for presence of THREE established gene markers

Incurable, but people can make decision whether or not they want to have children

No presence of enzyme: phenylalanine hydroxylase: converts amino acid phenylalanine to tyrosine. If this enzyme is not present,

<p>the accumulation of phenylalanine in bloodstream becomes toxic</p> <p>Results in damage to growing brain and thus produce extreme mental retardation</p> <p>And tendency towards epileptic seizures</p> <p>Failure to produce normal skin pigmentation</p> <p>With this, excessive amounts of phenylalanine in diet = dangerous</p> <p>Can be identified immediately after birth</p> Signup and view all the answers

<p>Blood sample taken by pricking baby's heel</p> <p>2-3 days after birth</p> <p>Special diets restricting intake of phenylalanine and replacing it with substitutes can, if begun early in child's life, large, if not entirely, correct the symptoms.</p> Signup and view all the answers

<p>One recessive allele</p> <p>Children with this suffer from chest infections, lack of digestive enzymes and increased salt loss</p> Signup and view all the answers

<p>Blood sample taken from baby's heel within 2-3 days after birth</p> <p>When child identified as having disease, given special diet low in fat and high in carbohydrate and protein</p> <p>Supplemented with pancreatic extract and large doses of vitamin A, D and K</p> <p>This does not cure the disease but enable child to function as normally as possible</p> <p>Couples concerned they may be carriers for cystic fibrosis can be tested via laboratory test done on a sample of blood saliva</p> <p>If both parents are carriers, genetic counselling should be done</p> Signup and view all the answers

<p>a specific sequence or variation in DNA that can be used to identify individuals, populations, or species</p> Signup and view all the answers

<p>a specific DNA pattern obtained from a person or sample of bodily tissue</p> Signup and view all the answers