Which of the following statements is true regarding achondroplasia?

Your patient presents for preconception counseling. She is 27 years old and has never been pregnant. Her husband is an achondroplastic dwarf. Which of the following statements is true regarding achondroplasia?

1.The inheritance pattern is autosomal recessive
2.It is rarely caused by a new genetic mutation
3.Affected women have a low incidence of cesarean section
4.Affected woman rarely live to reproductive age
5.Spinal stenosis is common

sol:

Achondroplasia, a congenital disorder of cartilage formation characterized by dwarfism, is associated with an autosomal dominant pattern of inheritance. However, new mutations account for 90% of all cases of the disorder. Affected women almost always require cesarean section because of the distorted shape of the pelvis. Achondroplastic fetuses, when prenatally diagnosed, should also be delivered by cesarean section to minimize trauma to the fetal neck. Women who have achondroplasia and receive adequate treatment for its associated complications generally have a normal life expectancy. The most common medical complaint in adulthood in patients with achondroplasia is symptomatic spinal stenosis.