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Figure 19-10 A ventricle shunt drains spinal fluid in
an infant with hydrocephalus.
Microcephaly can be a major health concern due
to the close link with this defect and exposure to the
Zika virus. Research studies suggest that pregnant
women who get Zika virus (most often through a mos
quito bite) have a high probability of passing the virus
to the unborn child, which may lead to microcephaly.
While symptoms of Zika are usually mild and include
fever, joint pain, rash, and redness of the eyes, symp
toms of Zika in the unborn child may include micro
cephaly and blindness.
■ Symptoms. The affected child may not only be
born with a smaller-than-normal head, but also the
head size usually remains smaller than normal as
the child grows. Dwarfism or short stature, delayed
motor, speech, and mental functions, seizures, bal
ance and coordination problems, and hyperactivity
may all be symptoms. Zika-infected babies may also
have neurologic damage with normal-size heads,
and some infected babies are unaffected and have no
symptoms. Unfortunately, most cases of Zika micro
cephaly will be severe, possibly requiring lifelong
intensive care.
■ Diagnosis. Diagnosis is confirmed with high-resolu
tion ultrasound.
■ Treatment. There is no treatment that can return
the child’s head to normal size. Treatment focuses on
symptoms and includes physical and speech therapies.
Medications may be used to control seizures and neu
romuscular symptoms.
■ Prevention. Genetic counseling may help parents
understand the risk for microcephaly in subsequent
pregnancies. Maternal factor-related microcephaly may
be prevented by avoiding toxins and viruses. The CDC
recommends that pregnant women should avoid any
geographic region with active Zika virus transmission.
There is currently no vaccine available for Zika virus;
however, there are a number of vaccines currently in
clinical trials.
Cerebral Palsy
■ Description. Cerebral palsy (CP) (SER-eh-bral
PAWL-zee) is a congenital bilateral paralysis that
results from inadequate blood or oxygen supply to the
brain during fetal development, during the birthing
process, or in infancy. CP is the most common dis
order affecting muscle function in children and more
often affects premature infants and male infants.
■ Etiology. Causes of CP include maternal rubella,
toxemia, birthing difficulties such as prolonged labor,
anoxia, hypoxemia, asphyxia from the umbilical cord
being wrapped around the infant’s neck, head trauma,
and meningitis. Often, the cause of CP is unknown.
■ Symptoms. This disorder usually affects motor or
muscle performance and can be noticed if the infant has
difficulty sucking or swallowing. Other complications
include visual and hearing deficits, seizure activity, and
mental challenges. CP is characterized by hyperactive
reflexes, rapid muscle contraction, and muscle weak
ness. The affected child commonly has a scissors gait,
exhibited by toe walking and crossing one foot over the
other with each step.
■ Diagnosis. Diagnosis is based on clinical symptoms
including posture, oral motor patterns, strabismus,
muscle tone, postural reaction, and tendon reflexes.
■ Treatment. There is no cure for CP. Treatment
involves physical therapy, speech therapy, orthopedic
casting, braces, and, often, surgery to help the child
reach full potential. Anticonvulsant and muscle relaxant
medications also can be beneficial.
458 Chapter 19
■ Prevention. There are no preventive measures.
Spina Bifida
■ Description. Spina bifida (SPY-nah BIF-ih-dah), a
neural tube defect (NTD), is a congenital disorder in
which one or more of the vertebrae of the bony spinal
column fails to close over the spinal cord, leaving an
opening in the column. Bifid means split in two parts,
which describes the vertebra in this condition. Develop
ment of the spinal cord and column occurs during the
first trimester of pregnancy.
■ Etiology. The cause of this malformation is unknown,
but risk factors include maternal radiation, virus, and
genetic factors. Children born with spina bifida are more
often born to mothers who have other children with this
defect. There are several other conditions that tend to
accompany spina bifida, including hydrocephalus, cleft
palate, and clubfoot. The several forms of spina bifida
are illustrated in Figure 19-11 and described as follows:
■ Spina bifida occulta The most common form
of spina bifida. A spina bifida is present, but it is
asymptomatic and hidden (occulta). Signs of the
malformation often include a dimpling of the skin
and a tuft of hair or port wine nevus on the skin
surface above the defect.
■ Meningocele Occurs when the meninges of the spi
nal cord protrude through the opening in the verte
bral column, forming a fluid-filled sac on the skin
surface. Because nerve tissue is not involved, the
infant usually does not have neurologic problems.
■ Myelomeningocele The most serious form of spina
bifida, because the meninges and a portion of the
spinal cord protrude through the opening in the
vertebral column, causing neurologic symptoms.
■ Sym ptoms. Depending on the type and cause,
common symptoms include skeletal malformation,
deformed joints, paralysis of the legs, and bowel and
bladder incontinence.
■ Diagnosis. The condition is suspected in the presence
of a skin defect over the spinal area along with mus
cular abnormalities in the legs and deformities of the
feet. The diagnosis is confirmed by X-ray examination
or myelography.
■ Treatment. Surgical intervention to correct the
condition is usually performed in the first 24 hours
of life. Additional procedures might be needed as
the child grows. Some of these children are unable
to walk and might die before the age of 2 or 3 years.
■ Prevention. There are no preventive methods,
although there is a link between folic acid (a B vitamin)
levels in pregnant women and major birth defects in
the baby’s brain and spine from NTDs. For this reason,
women need to take folic acid every day, starting before
they become pregnant, to help prevent NTDs.
Huntington’s Disease
■ Description. A rare, inherited disease that causes
progressive breakdown of nerve cells in the brain
(Figure 9-12). The disease affects the individual’s
(A) Spina bifida occulta
Figure 19-11 Types of spina bifida.
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HUNTINGTON S DISEASE
NORMAL BRAIN
Figure 19-12 Huntington’s disease.
ability to think and to move. As the disease progresses,
there is increasing mental deterioration and move
ment; it is characterized by chorea (involuntary muscle
jerking). It is also known as Huntington’s chorea.
■ Etiology. This disease is caused by a genetic defect
of chromosome 4. There is an adult-onset type and a
childhood or early-onset type. If a parent has the dis
ease, there is a 50% chance the offspring will also have
the defective gene and develop the disease at some time.
■ Symptoms. Behavior changes are the most common
symptoms. The person displays irritability, moodiness,
restlessness, abnormal movements, unsteady gait, and
an increasing dementia. Speech difficulties and tremors
are also common.
■ Diagnosis. The diagnosis is made based on scans, his
tory, genetic testing, and symptoms.
■ Treatment. There is no cure for the disease, but some
medications are prescribed to lessen the symptoms.
■ Prevention. There are no preventive measures
other than the decision of known disease carriers
not to reproduce. (Huntington’s disease is also dis
cussed in Chapter 15, “Nervous System Diseases and
Disorders.”)
Cardiovascular
The heart and its related great vessels are the most
common sites of congenital defects. The defects
Healthy Highlight
Genetic Testing
I
n the past few years, research in genetics is changing the way people look at their
family’s health history. So much more is known today than just a few years ago.
Looking at the results of genetic research can give an individual a new outlook on
disease prevention and treatment. Many diseases run in families including rare dis
eases like cystic fibrosis or hemophilia. Learning about one’s family history of disease
can give the individual a “heads up” for using early prevention strategies or be useful
for genetic counseling for couples planning to have children. Knowing one’s genetic
makeup can also affect the treatment regimen. Genetic tests can determine how the
body breaks down certain medications, so this helps the medical team find the correct
dose for that individual. These tests have been used to determine the correct dosage of
antidepressants that are used for some types of mental illness. However, there are some
concerns related to genetic testing such as discrimination at work or elsewhere and
how this information can affect the individual’s health insurance.
460 Chapter 19
can be small or quite large, and consequences of
these deformities can range from asymptomatic to
life-threatening. Collectively, these malformations
of heart structure are called congenital heart defects.
Congenital Heart Defects
■ Etiology. The cause of these defects is unknown, but a
genetic tendency is strongly suspected. Certain risk fac
tors include maternal rubella, poor maternal nutrition,
smoking, and alcoholism.
■ Symptoms. Symptoms of congenital heart defects
can vary from mild cases that are asymptomatic to
extreme conditions with symptoms of extreme cya
nosis, breathing difficulties, and very audible heart
murmurs.
■ Diagnosis. Diagnosis is made by electrocardiogram
and physical examination, including auscultation (lis
tening to the chest with a stethoscope), which usually
reveals heart murmurs (abnormal heart sounds) if
present.
■ Treatment. Early diagnosis and surgical correction of
these defects have improved drastically in recent years
and have significantly reduced the mortality rate of
infants born with heart defects.
■ Prevention. Controlling risk factors is the only pre
ventive measure.
Atrial Septal Defect
■ Description. Atrial septal defect is an opening between
the right and left atria (Figure 19-13A), commonly due
to the foramen ovale not closing at birth. The foramen
ovale is a natural opening between the atria that allows
blood to bypass the nonfunctional lungs during fetal life.
After the infant is born, the act of breathing causes a
change in chest cavity pressure that normally closes the
foramen ovale. Atrial septal defects allow oxygenated
blood to be pumped from the left atria to the right atria,
which is again pumped to the right ventricle and to the
lungs without ever circulating through the body. This
re-pumping causes an increased workload on the right
side of the heart. This defect occurs more commonly in
girls than in boys.
Ventricular Septal Defect
■ Description. Ventricular septal defects are the most
common heart defects, accounting for approximately
25% of all heart defects. As the name suggests, this
defect is a hole between the right and left ventri
cle (Figure 19-13B) that allows blood from the left
ventricle to flow into the right ventricle. Like the
atrial septal defect, this oxygenated blood has to be
re-pumped, causing an increased workload on the
right side of the heart.
Patent Ductus Arteriosus
■ Description. A ductus arteriosus is a connection
between the pulmonary artery and the aorta of the
normal fetal heart (Figure 19-13C) that allows blood
to flow from the pulmonary artery to the aorta, thus
bypassing the nonfunctional lungs. The ductus arte
riosus, like the foramen ovale, normally closes off
shortly after birth. If the structure does not close, or
remains patent, the condition is called patent ductus
arteriosus. With this condition, oxygenated blood
shunts abnormally from the higher-pressured aorta
back to the pulmonary artery. Once in the pulmonary
artery, the blood is recirculated to the lungs. This con
dition causes an increased workload on the heart and
pulmonary system and occurs twice as frequently in
girls as in boys.
Coarctation of the Aorta
■ Description. Coarctation is a stricture or narrow
ing. A coarctation of the aorta is a narrowing of the
descending or thoracic aorta (Figure 19-13D), a con
dition that causes a high blood pressure proximal to
the stricture and lower blood pressure distal to the
stricture. Infants or children affected with coarcta
tion of the aorta can have a high blood pressure in
the arms but a lower blood pressure in the legs. Coarc
tation increases the workload on the heart because the
heart attempts to pump blood through the narrowed
vessels.
Tetralogy of Fallot
■ Description. Tetralogy of Fallot (TET-traw-law-gee
of fall-OH) is a combination of four (tetra) defects
(Figure 19-13E) and is one of the most serious of
congenital heart defects. The four defects are as
follows:
1. Pulmonary valve stenosis The opening into the
pulmonary artery is too small, restricting the
amount of blood flow to the lungs.
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Genetic and Developmental Diseases and Disorders 461
Normal heart
(A) Atrial septal defect (B) Ventricular septal defect (C) Patent ductus arteriosus
(D) Coarctation of the aorta
Hypertrophy
(E) Tetralogy of Fallot
Figure 19-13 A normal heart and congenital heart defects (A-E).
2. Right ventricle hypertrophy This is due to the
increased workload on the right ventricle as it
attempts to pump blood through the stenotic
valve.
3. Ventricle septal defect This allows oxygen
ated blood to flow from the left ventricle to
the right.
4. Abnormal placement of the aorta The aorta
opens over the ventricle septal defect, allowing
blood from both ventricles to be pumped into
the aorta. The unoxygenated blood from the
right ventricle enters the general circulation
without passing through the lungs to become
oxygenated. This unoxygenated blood from
the right ventricle causes the tissues to become
cyanotic (blue).
■ Symptoms. Infants and children with tetralogy of
Fallot are truly blue babies. Cyanosis increases with
age, and clubbing of fingers and toes becomes evi
dent. Older children will rest in a squatting position
462 Chapter 19
to breathe easier. This position also increases venous
return. Other symptoms are growth retardation,
severe dyspnea with exercise, and frequent respira
tory infections.
Blood
Genetic and developmental disorders of the blood
are more common in certain population groups. For
example, some anemias are more commonly found in
Black populations, whereas other anemias are more
common in European populations. Sickle cell anemia
and hemophilia are both discussed in more detail in
Chapter 7, “Blood and Blood-Forming Organs Diseases
and Disorders.”
Sickle Cell Anemia
Sickle cell anemia is a chronic hereditary form of ane
mia found predominately in Black individuals.
Hemophilia
Hemophilia is an X-linked hereditary bleeding disorder
passed from a carrier mother to a son.
Consider This...
In one study, 90% of breast-fed children
had higher IQ scores than those who were
formula fed.
Digestive
Digestive system disorders, both genetic and devel
opmental, range from mild to severe. Many are diag
nosed at birth, especially if the disorder interferes with
ingestion, digestion, or elimination. Some of them are
incompatible with life and must be corrected immedi
ately or the infant will not survive.
■ Description. Several developmental malformations
occur in the digestive system.
■ Etiology. The cause of these disorders is unknown
but might be related to genetic tendencies or to mater
nal risk factors, including maternal rubella, poor mater
nal nutrition, smoking, and alcoholism.
A few of the more common malformations are
briefly discussed here.
Meckel’s Diverticulum
■ Description. This is an outpouching, or diverticu
lum, of the ileum (Figure 19-14A). During fetal life,
the intestine is connected to the yolk sac by a duct. Fail
ure of the duct to disappear leads to formation of this
diverticulum. Meckel’s diverticulum is the most com
mon malformation of the gastrointestinal (GI) system,
occurring in approximately 2% of the population. The
diverticulum might be asymptomatic the entire life of
the individual and found only on autopsy.
■ Symptoms. If symptoms do occur, it is usually during
infancy. The most common symptom is painless, bloody
stools.
Esophageal Atresia
■ Description. This is the absence of part of, or abnor
mal closure of, the esophagus. An atresia (ah-TREE-
ze-ah) is the congenital absence or closure of a normal
opening or lumen in the body and can occur in a variety
of areas. Esophageal atresia is often accompanied by a
fistula, called a tracheoesophageal fistula, connecting
the trachea to the esophagus (Figure 19-14B). This is
an emergency condition that allows food to pass directly
into the lung.
■ Symptoms. Reflux regurgitation of food occurs with
both atresias. If a fistula is present, extreme coughing,
cyanosis, and respiratory difficulties will appear.
Congenital Diaphragmatic Hernia
■ Description. This is a congenital hole in the dia
phragm. Abdominal organs might herniate through
this opening and into the chest cavity (Figure 19-14C).
■ Symptoms. Difficulty breathing and chest pain are
common symptoms.
Imperforate Anus
■ Description. This is a failure of the anus to connect to
the rectum (Figure 19-14D). Infants with imperforate anus
commonly have other developmental anomalies such as
those affecting the heart, kidneys, esophagus, and spine.
■ Symptoms. The primary symptom is not passing
stool. Other symptoms are abdominal cramping and
vomiting.
■ Diagnosis. Diagnosis is commonly made on the basis
of X-ray examination and ultrasound.
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(A) Meckel's diverticulum
(B) Esophageal atresia
(C) Congenital diaphragmatic hernia
(D) Imperforate anus
Figure 19-14 Digestive developmental malformations.
■ Treatment. Surgical correction is the treatment of
choice for these malformations.
■ Prevention. There are no preventive measures other
than controlling maternal risk factors.
Consider This...
The indention in the middle of the upper lip,
between the nose and the top of the upper
lip, is called the philtrum. Scientists have
been unable to determine its purpose.
Cleft Lip and Palate
■ Description. Cleft (a split) lip consists of one or more
abnormal splits in the upper lip (Figure 19-15A). This
is a common anomaly, occurring in approximately 1 in
1,000 births. The defect occurs more frequently in boys
and can vary from slight to severe.
A cleft palate involves the palate or roof of the
mouth (Figure 19-15B) and is more serious than a
cleft lip because it forms an opening between the
nasopharynx and the nose. Cleft palate is more com
mon in girls.
Both conditions can occur separately or in combi
nation and can range from mild to severe.
■ Etiology. The cause of clefts appears to be related
to a hereditary factor coupled with an alteration in
intra-uterine environment.
■ Symptoms. Symptoms of cleft lip are related to diffi
culty feeding and speaking and, if not corrected during
infancy, a struggle with positive self-image. Cleft palate
includes these symptoms plus an increased risk of respi
ratory and middle ear infections.
■ Diagnosis. Physical examination easily reveals
this disorder. X-ray and computerized tomography
(CT) may be utilized to determine the extent of the
malformation.
■ Treatment. Surgical repair for cleft deformities is usu
ally performed as soon as possible after birth. Several
(B)
I Figure 19-15 (A) Cleft lip. (B) Cleft palate.
surgeries might be necessary to achieve the desired
results. Special feeding devices and speech therapy are
common needs.
■ Prevention. The only means of prevention is con
trolling maternal risk factors.
Pyloric Stenosis
■ Description. Pyloric stenosis is a narrowing (stenosis)
of the outlet of the lower end of the stomach, the pylorus
(Figure 19-16). This condition is one of the most com
mon developmental abnormalities of the digestive tract.
■ Etiology. Pyloric stenosis is caused by a hypertrophy,
or thickening, of the pyloric sphincter, which controls
Hypertrophic pyloric muscle Stomach
Duodenum of
small intestine
the flow of contents out of the stomach or pyloric area.
The hypertrophy of the pyloric sphincter slows the flow
of stomach contents, resulting in a backup.
■ Symptoms. The most common symptom of pyloric
stenosis is projectile, or forceful, vomiting. Symptoms
of pyloric stenosis usually begin at two to four weeks of
age. This condition occurs almost exclusively in boys.
■ Diagnosis. Diagnosis is made from history and X-ray
examination (upper GI).
■ Treatment. A simple operation called a
pyloromyotomy (pyloro = pyloric, myo = muscle,
otomy = cut into), which involves incising and sutur
ing the pyloric sphincter muscle, can be performed to
correct the problem. This surgery is the standard treat
ment and is usually very effective.
■ Prevention. There are no known preventive measures.
Hirschsprung’s Disease
■ Description. Hirschsprung’s disease is due to an
absence of certain nerve cells (called parasympathetic
ganglion cells) in a segment of the colon, usually the
sigmoid colon. Without these nerve cells, the affected
segment of colon lacks peristalsis, causing massive dis
tention of the colon with feces (Figure 19-17).
■ Etiology. Hirschsprung’s disease is seen more often
in boys and those individuals with Down syndrome. It
has a familial tendency and occurs in approximately 1
in 5,000 births.
colon
Figure 19-16 Pyloric stenosis. Figure 19-17 Hirschsprung’s disease.
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Genetic and Developmental Diseases and Disorders 465
■ Symptoms. Common symptoms include chronic
constipation and abdominal distention.
■ Diagnosis. Diagnosis is made on the basis of a biopsy
to determine the absence of ganglion cells.
■ Treatment. Treatment is surgical removal of the
affected segment. A temporary colostomy might be
necessary to allow adequate healing of the colon.
■ Prevention. There is no known prevention. Genetic
counseling can be offered to discuss risk and treatment
options with couples if they have a previous child with
the condition and with those who have the condition
themselves and are considering pregnancy.
Phenylketonuria (PKU)
■ Description. PKU is an abnormal or faulty metabo
lism of the phenylalanine protein.
■ Etiology. PKU is a recessive genetic disorder.
■ Symptoms. Affected individuals do not produce the
enzyme necessary to break down the phenylalanine pro
tein, which then builds up in the blood and becomes
present in the urine. Phenylalanine is toxic to brain
cells and causes mental disability if the condition is not
corrected.
■ Diagnosis. Diagnosis is made by PKU blood testing
72 hours after birth or after the infant has ingested pro
teins. This testing is mandatory in the United States.
■ Treatment. Affected infants are placed on a pro
tein-restrictive diet. If the disease is discovered and
treated early, prognosis for normal intelligence is good.
If the condition is not discovered until after age 2 or 3
years, mental challenges are inevitable and irreversible.
■ Prevention. There are no preventive measures.
Genetic counseling can be offered to discuss risk and
treatment options with couples who have a previous
child with the condition and with those who have the
condition themselves and are considering pregnancy.
Urinary
Some genetic and developmental disorders of the uri
nary system, such as hypospadias or epispadias, can
be obvious at birth. Other disorders, such as Wilms’
tumor, might not present symptoms for many years. If
the condition interferes with elimination of urine, it is
incompatible with life.
Hypospadias and Epispadias
■ Description. Hypospadias is an abnormal congenital
opening of the male urinary meatus on the undersur
face of the penis (Figure 19-18A). This abnormality can
be mild, with the opening located just under the tip of
the penis, or it can be more severe, with locations mid
shaft or near the scrotum. Hypospadias is fairly com
mon, occurring in 1 in 200 boys.
Hypospadias can be accompanied by an abnormal
downward curvature of the penis called chordee (COR-
dee) (Figure 19-18B). The cause of chordee is an abnor
mal fibrous band of tissue.
Another similar but less common condition is epis
padias, characterized by the urinary meatus located on
the upper surface of the penis (Figure 19-18C).
■ Etiology. The cause of these conditions is unknown.
Recent research indicates that hypospadias risk factors
include an increase in risk in baby boys born to moth
ers who were age 35 or older and were considered obese
Complementary and Alternative Therapy
Herbs for Treatment
of Phenylketonuria
(PKU)
R
esearch was conducted looking at the disease phenylketonuria (PKU) and its effects
in the body to see if the use of phytocompounds from ayurvedic herbs would be
successful as a treatment strategy. The study used the ayurvedic herbs from wood bet-
ony, nettle, plantago ovate, turmeric, and dandelion. The researchers reported that the
phytocompounds from turmeric could be used successfully for phenylketonuria disease.
Curcumin is the phytocompound in turmeric. It has been widely used for its antioxidant
and anti-inflammatory properties but now it might have a new role as an additional
treatment for phenylketonuria. Further research is still needed in this area.
Source: Bagchi, Visvikis-Sieste, & Kar (2019)
(B) (C)
Figure 19-18 (A) Hypospadias. (B) Chordee. (C) Epispadias.
during pregnancy. Also, mothers who had fertility treat
ments had a higher risk of having a baby with hypospadias.
■ Symptoms. Abnormal position of urethra is the only
symptom. Chordee becomes worse with erection and
can lead to difficulty with sexual intercourse.
■ Diagnosis. Diagnosis is easily made with physical
examination.
■ Treatment. Mild cases of all these conditions can be
left untreated. Surgical repair is the treatment of choice
for severe cases. Male babies with hypospadias should
not be circumcised, as this tissue may be needed for
future surgical repair of the condition.
■ Prevention. There are no known preventive measures.
Wilms’ Tumor
■ Description. Wilms’ tumor is the most common
solid tumor affecting children and infants. This tumor
was named after Max Wilms, a German doctor who
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