Chapter 8-Infertility, Contraception, abortion

Question 1

What should a nurse be aware of with regard to the assessment of female, male, and couple infertility?
a. The couple’s religious, cultural, and ethnic backgrounds produce emotional
baggage that does not affect the clinical scientific diagnosis.
b. The investigation takes 3 to 4 months and a lot of money.
c. The woman is assessed first; if she is not the problem, the male partner is
analyzed.
d. Semen analysis is for men; the postcoital test is for women.

Answer 1

ANS: B
Fertility assessment and diagnosis take time, money, and commitment from the couple. Religious, cultural, and ethnic attitudes about fertility and related issues always have an impact on diagnosis and assessment. Both partners are assessed systematically and simultaneously, as individuals and as a couple. Semen analysis is for men, but the postcoital test is for the couple.

Question 2

2. A man smokes two packs of cigarettes a day. He wants to know if smoking is contributing to the difficulty he and his partner are having getting pregnant. What information is the basis for the nurse’s response?
   a. Indicating that the first sperm count seems okay
   b. Informing that only marijuana cigarettes affect sperm count
   c. Providing information about smoking and lung cancer and its lack of effect on sperm
   d. Providing education that smoking can reduce the quality of sperm

Answer 2

ANS: D
Use of tobacco, alcohol, and marijuana may affect sperm counts. Indicating that the first sperm count seems to be okay in the first semen analysis is inaccurate. Sperm counts vary from day to day and depend on emotional and physical status and sexual activity. Therefore, a single analysis may be inconclusive. A minimum of two analyses must be performed several weeks apart to assess male fertility.

Question 3

What should a nurse do when implementing a plan of care for infertile couples?
a. Reserve judgement about the couple until the relationship develops.
b. Avoid discussion of lifestyle changes that may enhance fertility.
c. Promote the use of herbs that might help the couple conceive.
d. Be knowledgeable about potential medication and surgical remedies.

Answer 3

ANS: D
Nurses should be open to and ready to help with a variety of pharmacological and nonpharmacological approaches. They should practice in a nonjudgemental manner at all times. When implementing a plan of care for infertile couples, the nurse should engage in discussions of lifestyle changes that may enhance fertility rather than avoid discussing them. Before the nurse promotes the use of herbs, it is important that the couple`s readiness for herbal remedies be assessed.

Question 4

1. Both parents are carriers of phenylketonuria (PKU). Their 2-year-old daughter has PKU. The couple tells a nurse that they are
   planning to have a second baby. Because their daughter has PKU, they are sure that their next baby won’t be affected. What
   information will the nurse use to formulate a response?
   a. The odds of having another baby with PKU are very slim.
   b. Each baby has a 50% chance of being affected.
   c. Males are not affected by PKU.
   d. The parents are both carriers so each baby has a 25% chance of being affected.

Answer 4

ANS: D
The chance is one in four that each child produced by this couple will be affected by PKU disorder. This couple still has an increased likelihood of having a child with PKU. Having one child already with PKU does not guarantee that they will not have another. No correlation exists between gender and inheritance of the disorder, because PKU is an autosomal recessive disorder.

Question 5

A nurse is providing genetic counselling for an expectant couple who already have a child with trisomy 18. What should the nurse do?
a. Tell the couple they need to terminate the pregnancy within 2 to 3 weeks.
b. Explain that the fetus has a 50% chance of having the disorder.
c. Discuss options, including amniocentesis, to determine whether the fetus is
affected.
d. Refer the couple to a psychologist for emotional support.

Answer 5

ANS: C
Genetic testing, including amniocentesis, would need to be performed to determine whether the fetus is affected. The couple should be given information about the likelihood of having another baby with this disorder so that they can make an informed decision. A genetic counsellor is the best source for determining genetic probability ratios. The couple eventually may need emotional support, but the status of the pregnancy must be determined first.

Question 6

A nurse is assessing the knowledge of new parents with a child born with maple syrup urine disease (MSUD). Which is accurate related to MSUD?
a. Both genes of a pair must be abnormal for the disorder to be present.
b. Only one copy of the abnormal gene is required for the disorder to be present.
c. The disorder occurs in males and heterozygous females.
d. The disorder is carried on the X chromosome.

Answer 6

ANS: A
MSUD is a type of autosomal recessive inheritance disorder in which both genes of a pair must be abnormal for the disorder to be expressed. MSUD is not an X-linked dominant disorder. MSUD is not a recessive disorder. MSUD is not an autosomal dominant inheritance disorder.

Question 7

A nurse is assessing the knowledge of new parents with a child born with maple syrup urine disease (MSUD). Which is accurate related to MSUD?
a. Both genes of a pair must be abnormal for the disorder to be present.
b. Only one copy of the abnormal gene is required for the disorder to be present.
c. The disorder occurs in males and heterozygous females.
d. The disorder is carried on the X chromosome.

Answer 7

ANS: A
MSUD is a type of autosomal recessive inheritance disorder in which both genes of a pair must be abnormal for the disorder to be expressed. MSUD is not an X-linked dominant disorder. MSUD is not a recessive disorder. MSUD is not an autosomal dominant inheritance disorder.

Question 8

During a presentation to obstetrical nurses interested in genetics, what does the genetic nurse identify as the primary factor to consider with genetic testing?
a. Anxiety and altered family relationships
b. Accessibility related to the availability of genetic testing
c. High false-positive rates associated with genetic testing
d. Ethnic and socioeconomic disparity associated with genetic testing

Answer 8

ANS: B
Decisions about genetic testing are shaped by accessibility of available genetic testing. The geographic location where the patient receives prenatal care and social norms are the primary factors to consider. Smaller rural communities in Canada do not offer the array of choices available in larger urban centres. Anxiety and altered family relationships, high false-positive rates, and ethnic and socioeconomic disparity are factors that may be difficulties associated with genetic testing, but they are not risks associated with testing.

Question 9

A man’s partner is pregnant for the third time. One child was born with cystic fibrosis and the other child is healthy. The man wonders what the chance is that this child will have cystic fibrosis. What is this type of testing known as?
a. Occurrence risk
b. Recurrence risk
c. Predictive testing
d. Predisposition testin

Answer 9

ANS: B
The couple already has a child with a genetic disease; therefore, they will be given a recurrence risk test. If a couple has not yet had children but are known to be at risk for having children with a genetic disease, they are given an occurrence risk test. Predictive testing is used to clarify the genetic status of an asymptomatic family member. Predisposition testing differs from presymptomatic testing in that a positive result does not indicate 100% risk of a condition developing.

Question 10

A couple has been counselled for genetic anomalies. They ask a nurse, “What is karyotyping?” The nurse’s response is based on which information related to karyotyping?
a. It will provide the status of lung maturity.
b. It is a predictor of normal fetal development.
c. It identifies fetal gender and chromosomal information.
d. It can detect physical deformities.

Answer 10

ANS: C
Karyotyping provides genetic information such as gender and chromosome structure. The lecithin-to-sphingomyelin (L/S) ratio, not karyotyping, reveals lung maturity. Although karyotyping can detect genetic anomalies, the range of normal is nondescriptive. Although karyotyping can detect genetic anomalies, not all such anomalies display obvious physical deformities. The term deformities is a nondescriptive word. Furthermore, physical anomalies may be present that are not detected by genetic studies (e.g., cardiac malformations).

Question 11

In practical terms regarding genetic health care, which should a nurse be aware of?
a. Genetic disorders equally affect all socioeconomic backgrounds, races, and ethnic
groups.
b. Genetic health care is more concerned with populations than individuals.
c. It is most important to provide emotional support to the family during genetic
counselling.
d. Taking genetic histories is only done in large university hospital and tertiary-care
centres.

Answer 11

ANS: C
Nurses should be prepared to help with a variety of stress reactions from a couple facing the possibility of a genetic disorder. Although anyone may have a genetic disorder, certain disorders appear more often in certain ethnic and racial groups. Genetic health care is highly individualized because treatments are based on the phenotypic responses of the individual. Individual nurses at any facility can take a genetic history, although larger facilities may have better support services.

Question 12

What should nurses be aware of with regard to prenatal genetic testing?
a. First-trimester screening can determine risk of carrying a fetus with Down
syndrome.
b. Carrier screening tests are used to look for gene mutations of people already
showing symptoms of a disease.
c. Predisposition testing predicts with near certainty that symptoms will appear.
d. Presymptomatic testing is used to predict the likelihood of breast cancer.

Answer 12

ANS: A
First-trimester screening (blood test combined with ultrasound screening) is used to identify risk for the neural tube defect and the specific chromosome abnormality involved in Down syndrome. Carriers of some diseases such as sickle cell disease do not display symptoms. Predisposition testing determines susceptibility such as for breast cancer; presymptomatic testing indicates that, if the gene is present, symptoms are certain to appear.

Question 13

With regard to the estimation and interpretation of the recurrence of risks for genetic disorders, what should a nurse be aware of?
a. With a dominant disorder, the likelihood of the second child also having the
condition is 100%.
b. An autosomal recessive disease carries a one in eight risk of the second child also
having the disorder.
c. Disorders involving maternal ingestion of drugs carry a one in four chance of
being repeated in the second child.
d. The risk factor remains the same no matter how many affected children are
already in the family.

Answer 13

ANS: D
Each pregnancy is an independent event. The risk factor (e.g., one in two, one in four) remains the same for each child, no matter how many children are born to the family. In a dominant disorder the likelihood of recurrence in subsequent children is 50% (one in two). An autosomal recessive disease carries a one in four chance of recurrence. Subsequent children would be at risk only if the mother continued to take drugs; the rate of risk would be difficult to calculate.

Question 14

What is the term for an individual’s genetic makeup? a. Genotype
b. Phenotype
c. Karyotype
d. Chromotype

Answer 14

ANS: A
The genotype comprises all the genes the individual can pass on to a future generation. The phenotype is the observable expression of an individual’s genotype. The karyotype is a pictorial analysis of the number, form, and size of an individual’s chromosomes. Genotype refers to an individual’s genetic makeup.

Question 15

What should a nurse be aware of with regard to chromosome abnormalities?
a. They occur in approximately 10% of newborns.
b. Abnormalities of number are the leading cause of pregnancy loss.
c. Down syndrome is a result of an abnormal chromosome structure.
d. Unbalanced translocation results in a mild abnormality that the child will outgrow.

Answer 15

ANS: B
Aneuploidy is an abnormality of number that also is the leading genetic cause of intellectual disability. Chromosome abnormalities occur in fewer than 1% of newborns. Down syndrome is the most common form of trisomal abnormality, an abnormality of chromosome number (47 chromosomes). Unbalanced translocation is an abnormality of chromosome structure that often has serious clinical effects.

Question 16

A pregnant patient asks a nurse when congenital heart anomalies occur during fetal development. The nurse’s response is based on which information?
a. It is unknown when such defects occur.
b. The timing depends on the cause of the defect.
c. They occur between the third and fifth weeks of fetal development.
d. They most often occur in the first 2 weeks of pregnanc

Answer 16

ANS: C
The cardiovascular system is the first organ system to function in the developing human. Blood vessel and blood formation begin in the third week, and the heart is developmentally complete in the fifth week. “We don’t really know when such defects occur” is an inaccurate statement. Regardless of the cause, the heart is vulnerable during its period of development, the third to fifth weeks. “They usually occur in the first 2 weeks of development” is an inaccurate statement.

Question 17

A pregnant woman at 25 weeks’ gestation tells a nurse that she dropped a pan last week and her baby jumped at the noise. The nurse’s response is based on which information?
a. Babies can’t respond to noise at 25 weeks’ gestation.
b. Abrupt noise can cause the aural reflex.
c. Babies respond to extrauterine sound beginning at about 24 weeks of gestation.
d. This is an abnormal finding and should be reported to the health care provider.

Answer 17

ANS: C
“Babies respond to sound starting at about 24 weeks of gestation” is an accurate statement because fetuses respond to sound by 24 weeks. “That must have been a coincidence; babies can’t respond like that” is inaccurate. Acoustic stimulations can evoke a fetal heart rate response. There is no such thing as an aural reflex. The statement, “Let me know if it happens again; we need to report that to your midwife” is not appropriate; it gives the impression that something is wrong.

Question 18

At approximately how many weeks of gestation does lecithin form on the alveolar surfaces, the eyelids open, and the fetus measure approximately 27 cm crown to rump, and weigh approximately 1100 g?
a. 20 weeks
b. 24 weeks
c. 26 weeks
d. 28 weeks

Answer 18

ANS: D
These are all milestones in human development that occur at approximately 28 weeks.

Question 19

A nurse caring for the laboring woman should know that meconium is produced by
a. fetal intestines.
b. fetal kidneys.
c. amniotic fluid.
d. the placenta.

Answer 19

ANS: A
As the fetus nears term, fetal waste products accumulate in the intestines as dark green-to-black, tarry meconium.

Question 20

A woman asks a nurse, “What protects my baby’s umbilical cord from being squashed while the baby’s inside of me?” The nurse’s response is based on which information?
a. The umbilical cord is surrounded by connective tissue called Wharton jelly.
b. The umbilical cord floats around in blood.
c. Nothing really protects the cord but it is unlikely to be squashed.
d. The umbilical cord is a group of blood vessels that are protected by the placenta.

Answer 20

ANS: A
“Wharton’s jelly prevents compression of the blood vessels and ensures continued nourishment of your baby” is accurate information. The cord does not float around in blood. The statement “Nothing protects the cord” is not true. The placenta does not protect the umbilical cord; the cord is protected by the surrounding Wharton jelly.

Question 21

What is responsible for the transportation of oxygen and carbon dioxide to and from the maternal bloodstream?
a. Decidua basalis
b. Blastocyst
c. Germ layer
d. Chorionic villi

Answer 21

ANS: D
Chorionic villi are fingerlike projections that develop out of the trophoblast and extend into the blood-filled spaces of the endometrium. The villi obtain oxygen and nutrients from the maternal bloodstream and dispose of carbon dioxide and waste products into the maternal blood. The decidua basalis is the portion of the decidua (endometrium) under the blastocyst where the villi attach. The blastocyst is the embryonic development stage after the morula. Implantation occurs at this stage. The germ layer is a layer of the blastocyst.

Question 22

A woman who is 8 months pregnant asks the nurse, “Does my baby have any antibodies to fight infection?” The nurse’s response is based on which information?
a. At 8 months all of the immunoglobulins (Ig) are present.
b. Antibodies are transferred to the baby only during birth.
c. Babies do not have any antibodies to fight infection until after birth.
d. During pregnancy, babies only acquire IgG and IgM.

Answer 22

ANS: D
During the third trimester, it is only IgG that crosses the placenta; IgG, provides passive acquired immunity to specific bacterial toxins. The fetus produces IgM by the end of the first trimester. So by the third trimester the fetus has IgG and IgM. IgA is not produced by the baby; breastfeeding supplies the baby with IgA.

Question 23

The measurement of lecithin in relation to sphingomyelin (L/S ratio) is used to determine fetal lung maturity. Which ratio reflects maturity of the lungs?
a. 1.4:1
b. 1.8:1
c. 2:1
d. 1:1

Answer 23

ANS: C
A ratio of 2:1 indicates a two-to-one ratio of L/S, an indicator of lung maturity. Ratios of 1.4:1, 1.8:1, and 1:1 indicate immaturity of the fetal lungs.

Question 24

During an initial prenatal appointment, a pregnant patient asks a nurse how their baby gets air while in the uterus. The nurse’s response is based on which information?
a. The baby’s lungs work in utero to exchange oxygen and carbon dioxide.
b. The baby absorbs oxygen from the mother’s blood system.
c. The placenta provides oxygen to the baby and excretes carbon dioxide into the mother’s bloodstream.
d. The placenta delivers oxygen-rich blood through the umbilical artery to the
baby’s abdomen.

Answer 24

ANS: C
The placenta functions by supplying oxygen and excreting carbon dioxide to the maternal bloodstream. The fetal lungs do not function for respiratory gas exchange in utero. The baby does not simply absorb oxygen from a woman’s blood system. Blood and gas transport occur through the placenta. The placenta delivers oxygen-rich blood through the umbilical vein, not the artery.

Question 25

Which is the most basic information a perinatal nurse should know concerning conception?
a. Ova are considered fertile 48 to 72 hours after ovulation.
b. Sperm remain viable in the woman’s reproductive system for an average of 12 to
24 hours.
c. Conception is achieved when a sperm successfully penetrates the membrane
surrounding the ovum.
d. Implantation in the endometrium occurs 6 to 10 days after conception

Answer 25

ANS: D
After implantation, the endometrium is called the decidua. Ova are considered fertile for about 24 hours after ovulation. Sperm remain viable in the woman’s reproductive system for an average of 2 to 3 days. Penetration of the ovum by the sperm is called fertilization. Conception occurs when the zygote, the first cell of the new individual, is formed.

Question 26

A perinatal nurse should be aware of which fact about the amniotic fluid?
a. It serves as a source of oral fluid and a repository for waste from the fetus.
b. The volume remains about the same throughout the term of a healthy pregnancy.
c. A volume of less than 300 mL is associated with gastrointestinal malformations.
d. A volume of more than 2 L is associated with fetal renal abnormalities.

Answer 26

ANS: A
Amniotic fluid serves as a source of oral fluid and a repository for waste from the fetus, and it cushions the fetus and helps maintain a constant body temperature. The volume of amniotic fluid changes constantly. Too little amniotic fluid (oligohydramnios) is associated with renal abnormalities. Too much amniotic fluid (hydramnios) is associated with gastrointestinal and other abnormalities.

Question 27

With regard to the structure and function of the placenta, a perinatal nurse should be aware of which information?
a. As the placenta widens, it gradually thins to allow easier passage of air and
nutrients.
b. As one of its early functions, the placenta acts as an endocrine gland.
c. The placenta is able to keep out most potentially toxic substances.
d. Optimal blood circulation is achieved through the placenta when the woman is
lying on her back or standing.

Answer 27

ANS: B
The placenta produces four hormones necessary to maintain the pregnancy. The placenta widens until week 20 and continues to grow thicker. Toxic substances such as nicotine and carbon monoxide readily cross the placenta into the fetus. Optimal circulation occurs when the woman is lying on her side.

Question 28

Which should a nurse be aware of with regard to the development of the respiratory system?
a. The respiratory system does not begin developing until after the embryonic stage.
b. The infant’s lungs are considered mature when the lecithin/sphingomyelin (L/S)
ratio is 1:1, at about 32 weeks.
c. Maternal hypertension can reduce maternal-placental blood flow, accelerating
lung maturity.
d. Fetal respiratory movements are not visible on ultrasound scans until at least 16
weeks.

Answer 28

ANS: C
A reduction in placental blood flow stresses the fetus, increases blood levels of corticosteroids, and thus accelerates lung maturity. Development of the respiratory system begins during the embryonic phase and continues into childhood. The infant’s lungs are mature when the L/S ratio is 2:1, at about 35 weeks. Lung movements have been seen on ultrasound scans at 11 weeks.

Question 29

What should a nurse be able to tell parents when they have questions about multiple births?
a. Multiple births are increasing because of the use of fertility drugs.
b. Dizygotic twins (two fertilized ova) have the potential to be conjoined twins.
c. Identical twins are more common in White families.
d. Fraternal twins are same gender, usually male.

Answer 29

ANS: A
Multiple births and twinning are on the rise given the use of fertility drugs and delayed child-bearing. Conjoined twins are monozygotic; they are from a single fertilized ovum in which division occurred very late. Identical twins show no racial or ethnic preference; fraternal twins are more common among Black women. Fraternal twins can be of different gender or the same gender. Identical twins are the same gender.

Question 30

A nurse caring for a pregnant patient knows that their health teaching regarding fetal circulation has been effective when the patient reports that they have been sleeping in which position?
a. In a side-lying position
b. On her back with a pillow under her knees
c. With the head of the bed elevated
d. On her abdomen

Answer 30

ANS: A
Optimal circulation is achieved when the woman is lying at rest on her side. Decreased uterine circulation may lead to intrauterine growth restriction. Previously it was believed that the left lateral position promoted maternal cardiac output, thereby enhancing blood flow to the fetus. However, it is now known that either side-lying position enhances uteroplacental blood flow. If a woman lies on her back with the pressure of the uterus compressing the vena cava, blood return to the right atrium will be diminished. Although this position is recommended and ideal for later in pregnancy, the woman must still maintain a lateral tilt to the pelvis to avoid compression of the vena cava. Many women will find this position uncomfortable as pregnancy advances. Side-lying is the ideal position to promote blood flow to the fetus.

Question 31

At what age is the embryo or fetus less susceptible to teratogens?
a. 4 weeks
b. 6 weeks
c. 8 weeks
d. 10 weeks

Answer 31

ANS: D
The fetus is less susceptible to teratogens than the embryo. The embryo at 4 weeks is more susceptible than the fetus at 10 weeks. The embryo at 6 weeks is more susceptible than the fetus at 10 weeks. The embryo at 8 weeks is more susceptible than the fetus at 10 weeks.

Question 32

The placenta allows exchange of oxygen, nutrients, and waste products between the mother and fetus by
a. contact between maternal blood and fetal capillaries within the chorionic villi.
b. interaction of maternal and fetal pH levels within the endometrial vessels.
c. a mixture of maternal and fetal blood within the intervillous spaces.
d. passive diffusion of maternal carbon dioxide and oxygen into the fetal capillaries.

Answer 32

ANS: A
Fetal capillaries within the chorionic villi are bathed with oxygen-rich and nutrient-rich maternal blood within the intervillous spaces. The endometrial vessels are part of the uterus. There is no interaction with the fetal blood at this point. Maternal and fetal bloods do not normally mix. Maternal carbon dioxide does not enter into the fetal circulation.

Question 33

Congenital disorders refer to conditions that are present at birth. These disorders may be inherited and caused by environmental factors or maternal malnutrition. Toxic exposures have the greatest effect on development between 15 and 60 days of gestation. For the nurse to be able to conduct a complete assessment of the newly pregnant patient, the nurse should understand the significance of exposure to known human teratogens. These include (Select all that apply.)
a. infections.
b. radiation.
c. maternal conditions.
d. drugs.
e. chemicals.

Answer 33

ANS: A,B,C,D,E
Exposure to radiation and numerous infections may result in profound congenital deformities. These include but are not limited to varicella, rubella, syphilis, parvovirus, cytomegalovirus, and toxoplasmosis. Certain maternal conditions such as diabetes and phenylketonuria may also affect organs and other parts of the embryo during this developmental period. Medications such as antiseizure medication and some antibiotics as well as chemicals, including lead, mercury, tobacco, and alcohol, also may result in structural and functional abnormalities.

Question 34

A nurse is aware that which congenital malformations result from multifactorial inheritance? (Select all that apply.)
a. Cleft lip
b. Congenital heart disease
c. Cri du chat syndrome
d. Anencephaly
e. Pyloric stenosis

Answer 34

ANS: A, B, D, E
All these congenital malformations are associated with multifactorial inheritance. Cri du chat syndrome is related to a chromosome deletion.

Question 35

Along with gas exchange and nutrient transfer, the placenta produces many hormones necessary for normal pregnancy. These include (Select all that apply.)
a. human chorionic gonadotropin (hCG).
b. insulin.
c. estrogen.
d. progesterone.
e. testosterone.

Answer 35

ANS: A, C, D
hCG causes the corpus luteum to persist and produce the necessary estrogens and progesterone for the first 6 to 8 weeks. Estrogens cause enlargement of the woman’s uterus and breasts; cause growth of the ductal system in the breasts; and, as term approaches, play a role in the initiation of labour. Progesterone causes the endometrium to change, providing early nourishment. Progesterone also protects against spontaneous abortion by suppressing maternal reactions to fetal antigens and reduces unnecessary uterine contractions. Other hormones produced by the placenta include hCT, hCA, and numerous growth factors. Human placental lactogen promotes normal nutrition and growth of the fetus and maternal breast development for lactation. This hormone decreases maternal insulin sensitivity and utilization of glucose, making more glucose available for fetal growth. If a Y chromosome is present in the male fetus, hCG causes the fetal testes to secrete testosterone necessary for the normal development of male reproductive structures.

Question 36

Which factors are known to delay fetal lung maturity? (Select all that apply.)
a. Maternal hypertension
b. Gestational diabetes
c. Chronic glomerulonephritis
d. Infection
e. Maternal corticosteroid use
f. Epilepsy

Answer 36

ANS: B, C
Gestational diabetes and chronic glomerulonephritis can delay fetal lung maturity. Certain maternal conditions that cause decreased maternal placental blood flow, such as maternal hypertension, placental dysfunction, infection, or corticosteroid use, accelerate lung maturity.

Question 37

Which are autosomal dominant disorders? (Select all that apply.)
a. Myotonic dystrophy
b. PKU
c. Marfan syndrome
d. Dwarfism
e. Maple syrup urine disease
f. Cystic fibrosis

Answer 37

ANS: A, C, D
Examples of autosomal dominant disorders are Marfan syndrome, neurofibromatosis, myotonic dystrophy, Stickler syndrome, Treacher Collins syndrome, and achondroplasia (dwarfism).