Three-year-old Tawny Fitzgerald has been to the emergency department repeatedly

Question

Three-year-old Tawny Fitzgerald has been to the emergency department repeatedly for broken bones. At the last visit, a nurse questioned Tawny’s parents, Donald and Rebecca, about possible child abuse. No charges were filed—the child just appeared to be clumsy. Then Tawny’s brother Winston was born. When he was six months old, Donald found him screaming in pain one morning. A trip to the hospital revealed a broken arm. This time, a social worker was sent to the Fitzgerald home. Donald and Rebecca were interviewed in great depth and advised to find a lawyer. A relative in medical school suggested that they have the children examined for osteogenesis imperfecta, also known as “brittle bone disease.” Consult OMIM and list the facts about a form of this condition that could affect both sexes, with carrier parents. If you were the genetic counselor hired to help this couple, what would you ask them, and tell them, to help them deal with the legal and social services authorities who might need a biology lesson?

Explanation / Answer

osteogenesis imperfecta is the result of the mutation in one of the two genes that carry instructions for making type 1 collagen ( a major protein in bones and muscles).

the mutation may result in either change in the structure of type 1 collagen or in the number of the collagen molecules made.

either of these changes may result in weak bones that fracture easily.

osteogenesis imperfecta in families

there are essentially the following scenarios that occur to cause a child to be born with osteogenesis imperfecta.

1. DIRECT INHERITANCE FROM A PARENT

a person with osteogenesis imperfecta have two genes for type 1 collagen - one gene is faulty , the other is normal.

each time that person concieves a child , he or she passes on one of the two genes to the child.

therefore there are 50% chances that his child will inherit the faulty gene.

if the child inherit the faulty gene, he or she will have the same type of OI as the parent.

if the parent with OI passes on his or her normal gene to a child , that child will not have OI and cannot pass to next generations.

WHEN BOTH THE PARENTS HAVE OI

if two people with OI have a child , there are 75% of chances that child will inherit one or both OI genes.

there are 25% chances that the child will inherit only the mother's OI gene.

a 25% of chances that the child will inherit only the father's OI gene,

a 25% chances , the child will inherit both parents OI genes.

because this situation has been uncommon , the outcome of a child inherit two OI gene hard to predict.

it is likely that the child would have a severe , possibly lethal form of the disorder.

BEING A GENETIC COUNCILLOR I WILL ASK " DO ANY MEMBER OF YOUR FAMILY ALSO HAVE THE SAME DISEASE " ???

BECAUSE ITS A GENETIC DISEASE AND IT PASSES FROM ONE GENERATION TO NEXT GENERATION.

IT IS A GENETIC DISEASE , AND THERE ARE ALSO CHANCES THAT THE SAME DISEASE CAN PASS TO NEXT FUTURE GENERATION.

SO SOME DIAGNOSTIC MEASURES MUST BE TAKEN WHILE THE BABY IS IN THE PRENATAL CONDITION.

THESE MEASURES CAN BE ULTRASOUND, CHORIONIC VILLUS SAMPLING( examines placental cells), AMNIOCENTESIS (examine fetal cells.) ETC.

SO THAT PROPER PREVENTIVE MEASURES CAN BE TAKEN.

AND THERE ARE ALSO SOME ORGANISATIONS WHICH HELP THE PEOPLE WITH OI.

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