Question

A couple planning their family are aware that through the past three generations on the husband's side a substantial number of stillbirths have occurred and several malformed babies were born who died early in childhood. The wife has studied genetics and urges her husband to visit a genetic counseling clinic, where a complete karyotype-banding analysis is performed. Although the tests show that he has a normal complement of 46 chromosomes, banding analysis reveals that one member of the chromosome 1 pair (in group A) contains an inversion covering 70 percent of its length. The homolog of chromosome 1 and all other chromosomes show the normal banding sequence. (a) how would you explain the high incidence of past stillbirths?(b) What can you predict about the probability of abnormality/ normality of their future children? (c) Would you advise the woman that she will have to bring each pregnancy to term to determine whether the fetus is normal? If not, what else can you suggest?

Answer 1

Answer:

Genetic counselling

Explanation:

About 15-25% of babies that are still-born are due to a defect on their chromosomes and a total 20% of still-born babies are due to a defect on chromosome one.  Since chromosome one is the largest 70% of damage will cause significant mutation and definitely, still birth.

a) The High incidence of still birth could be due to both parents carrying a defective copy of Chromosome one. There is a 25% chance of inheriting both copies from parents. The parents are unaffected because they have a normal copy but are carriers of the abnormal copy.

b)There is a possibility that the children are all normal and 50% of them will be carriers or the abnormal chromosome. This is only likely if the woman has two normal copies and no other underlying mutations.

c)There are now advancements in fertility and her options are many. She can opt for in vitro assistance where the affected male gametes are filtered out. Also she can do various tests while the child is still in the womb to determine the genetic predisposition. Decisions can be made after the results are given.

It is highly suggested that this woman and her husband undergo genetic counselling if they are to fully understand their condition and produce healthy children.