Sickle cell anaemia is due to

All sons of a couple are colourblind because

Which disease is caused by a gene defect located on chromosome $16$,leading to a deficiency that affects the transport of respiratory gases?

Pick out the correct statements.
$(1)$ Haemophilia is a sex-linked recessive disease.
$(2)$ Down's syndrome is due to aneuploidy.
$(3)$ Phenylketonuria is an autosomal recessive gene disorder.
$(4)$ Sickle cell anaemia is an $X$-linked recessive gene disorder.

What will be the genotypes of the parents of a colorblind daughter and a colorblind son?

$A$ woman is a carrier for hemophilia (having one gene on each $X$ chromosome) and also carries one gene for color blindness on one $X$ chromosome. She marries a normal man. What will be the phenotype of their offspring?