Cleft lip and palate..
Cleft lip and palate
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Cleft
lip (cheiloschisis) and cleft palate (palatoschisis), which can also
occur together as cleft lip and palate, are variations of a type of
clefting congenital
deformities caused
by abnormal facial development during gestation.
A cleft is a fissure or opening—a gap. It is the non-fusion of the
body's natural structures that form before birth.
Clefts
can also affect other parts of the face, such as the eyes, ears,
nose, cheeks, and forehead. In 1976, Paul
Tessierdescribed
fifteen lines of cleft. Most of these craniofacial clefts are even
rarer and are frequently described as Tessier clefts using the
numerical locator devised by Tessier.
A
cleft lip or palate can be successfully treated with surgery,
especially so if conducted soon after birth
or
in early childhood.
Approximately
1 in 700 children born have a cleft lip or a cleft palate or both.
Cleft lip and palate resulted in about 3,300 deaths in 2013 down from
7,600 deaths in 1990.
In
decades past, the condition was sometimes referred to a sharelip,
based on the similarity to the cleft in the lip of a hare,
but that term is now generally considered to be offensive.
Symptoms:
- A split in the lip and roof of the mouth (palate) that can affect one or both sides of the face
- A split in the lip that can appear as only a small notch in the lip or can extend from the lip through the upper gum and palate into the bottom of the nose
- A split in the roof of the mouth (palate) that doesn't affect the appearance of the face
Less
commonly, a cleft occurs only in the muscles of the soft palate
(submucous cleft palate), which are at the back of the mouth and
covered by the mouth's lining. This type of cleft often goes
unnoticed at birth and may not be diagnosed until later when signs
develop. Signs and symptoms of submucous cleft palate may include:
- Difficulty swallowing
- Nasal speaking voice
- Recurring ear infections
A
cleft lip and cleft palate are usually apparent at birth, and your
doctor may start coordinating care at that time. If your baby has
signs and symptoms of a submucous cleft palate, such as difficulty
with feedings, make an appointment with your child's doctor.
Cause:
The
development of the face is coordinated by complex morphogenetic
events and rapid proliferative expansion, and is thus highly
susceptible to environmental and genetic factors, rationalising the
high incidence of facial malformations. During the first six to eight
weeks of pregnancy, the shape of the embryo's head is formed. Five
primitive tissue lobes grow:
a)
one from the top of the head down towards the future upper lip;
(Frontonasal Prominence)
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b)two
from the cheeks, which meet the first lobe to form the upper lip;
(Maxillar Prominence)
c)
and just below, two additional lobes grow from each side, which
form the chin and lower lip; (Mandibular Prominence)
If
these tissues fail to meet, a gap appears where the tissues should
have joined (fused). This may happen in any single joining site, or
simultaneously in several or all of them. The resulting birth defect
reflects the locations and severity of individual fusion failures
(e.g., from a small lip or palate fissure up to a completely
malformed face).
The
upper lip is formed earlier than the palate, from the first three
lobes named a to c above. Formation of the palate is the last step in
joining the five embryonic facial lobes, and involves the back
portions of the lobes b and c. These back portions are called palatal
shelves, which grow towards each other until they fuse in the
middle.This process is very vulnerable to multiple toxic substances,
environmental pollutants, and nutritional imbalance. The biologic
mechanisms of mutual recognition of the two cabinets, and the way
they are glued together, are quite complex and obscure despite
intensive scientific research.
Genetics:
Genetic
factors contributing to cleft lip and cleft palate formation have
been identified for some syndromic
cases, but knowledge
about genetic factors that contribute to the more common isolated
cases of cleft lip/palate is still patchy.
Many
clefts run in families, even though in some cases there does not seem
to be an identifiable syndrome present,
possibly because of
the current incomplete genetic understanding of midfacial
development.
A
number of genes are involved including cleft
lip and palate transmembrane protein andGAD1,one
of the glutamate
decarboxylases.
Many genes are known to play a role in craniofacial development and
are being studied through the facebase
initiative
for their part in clefting. These genes are AXIN2,
BMP4,
FGFR1,FGFR2,
FOXE1,
IRF6,
MAFB
(gene),
MMP3,
MSX1,
MSX2 (Msh
homeobox 2),
MSX3, PAX7,
PDGFC,
PTCH1,
SATB2,
SOX9,
SUMO1 (Small
ubiquitin-related modifier 1),
TBX22,
TCOF (Treacle
protein),
TFAP2A,
VAX1,
TP63,
ARHGAP29,
NOG, NTN1,
WNT genes, and locus 8q24.[24]
Syndromes
- The Van der woude syndrome is caused by a specific variation in the gene IRF6 that increases the occurrence of these deformities threefold.
- Another syndrome, Siderius X-linked mental retardation, is caused by mutations in the PHF8 gene (OMIM 300263); in addition to cleft lip and/or palate, symptoms include facial dysmorphism and mild mental retardation.
In
some cases, cleft palate is caused by syndromes which also cause
other problems.
- Hardikar syndrome can cause cleft lip and palate, Hydronephrosis, intestinal obstructionand other symptoms.
- Cleft lip/palate may be present in many different chromosome disorders including patau syndrome (trisomy 13).
Environment:
Environmental
influences may also cause, or interact with genetics to produce,
orofacial clefting. An example for how environmental factors might be
linked to genetics comes from research on mutations in the gene PHF8
that
cause cleft lip/palate (see above). It was found that PHF8
encodes
for a histone
lysine
demethylase,
and
is involved in epigenetic
regulation.
The catalytic activity of PHF8 depends on molecular oxygen,a
fact considered important with respect to reports on increased
incidence of cleft
lip/palate in
mice that have been exposed to hypoxia
early
during pregnancy.
In
humans, fetal
cleft
lip and other congenital abnormalities
have
also been linked to maternal hypoxia, as caused by e.g. maternal
smoking,
maternal
alcohol
abuse or
some forms of maternal hypertensiontreatment.Other
environmental factors that have been studied include: seasonal causes
(such as pesticide exposure); maternal diet and vitamin intake;
retinoids — which are members of the vitamin A family;
anticonvulsant
drugs;
alcohol; cigarette use; nitrate compounds; organic solvents; parental
exposure to lead; and illegal drugs (cocaine, crack cocaine, heroin,
etc.).
Current
research continues to investigate the extent to which folic
acid can reduce the
incidence of clefting.
Tests
and diagnosis:
Ultrasound
to diagnose cleft lip and cleft palate before birth
Increasingly,
cleft lip and cleft palate are being diagnosed by ultrasound before
the baby is born. An ultrasound is a test that uses sound waves to
create pictures of the developing fetus. When analyzing the pictures,
a doctor may detect an abnormality in the facial structures.
Cleft lip may be
detected with ultrasound beginning around the 18th week of pregnancy.
As the fetus continues developing, it may be easier to accurately
diagnose a cleft lip. Cleft palate that occurs on its own is more
difficult to diagnose using ultrasound, since it can be difficult to
see inside the fetus' mouth.
If
fetal ultrasound shows a cleft, your doctor may offer a procedure to
take a sample of amniotic fluid from your uterus (amniocentesis).
Analyzing the fluid may reveal abnormalities that indicate the fetus
has inherited a genetic syndrome that can cause other birth defects.
However, most often cleft lip and cleft palate occur on their own.
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The
Treatment for Cleft Lip and Cleft Palate:
A
cleft lip may require one or two surgeries depending on the extent of
the repair needed. The initial surgery is usually performed by the
time a baby is 3 months old.
Repair
of a cleft palate often requires multiple surgeries over the course
of 18 years. The first surgery to repair the palate usually occurs
when the baby is between 6 and 12 months old. The initial surgery
creates a functional palate, reduces the chances that fluid will
develop in the middle ears, and aids in the proper development of the
teeth and facial bones.
Children
with a cleft palate may also need a bone graft when they are about 8
years old to fill in the upper gum line so that it can support
permanent teeth and stabilize the upper jaw. About 20% of children
with a cleft palate require further surgeries to help improve their
speech.
Once
the permanent teeth grow in, braces are often needed to straighten
the teeth.
Additional
surgeries may be performed to improve the appearance of the lip and
nose, close openings between the mouth and nose, help breathing, and
stabilize and realign the jaw. Final repairs of the scars left by the
initial surgery will probably not be performed until adolescence,
when the facial structure is more fully developed.
Dental Care for Children With Cleft Lips and/or Palates:
Generally,
the preventive and restorative dental care needs of children with
clefts are the same as for other children. However, children with
cleft lip and cleft palate may have special problems related to
missing, malformed, or malpositioned teeth that require close
monitoring.
- Early dental care Like other children, children born with cleft lip and cleft palate require proper cleaning, good nutrition , and fluoride treatment in order to have healthy teeth. Appropriate cleaning with a small, soft-bristled tooth brush should begin as soon as teeth erupt. If a soft children's toothbrush will not adequately clean the teeth because of the modified shape of the mouth and teeth, a toothette may be recommended by your dentist. A toothette is a soft, mouthwash-containing sponge on a handle that's used to swab teeth. Many dentists recommend that the first dental visit be scheduled at about 1 year of age or even earlier if there are special dental problems. Routine dental care can begin around 1 year of age.
- Orthodontic care. A first orthodontic appointment may be scheduled before the child has any teeth. The purpose of this appointment is to assess facial growth, especially jaw development. After teeth erupt, an orthodontist can further assess a child's short and long-term dental needs. After the permanent teeth erupt, orthodontic treatment can be applied to align the teeth.
- Prosthodontic care. A prosthodontist is a member of the cleft palate team. He or she may make a dental bridge to replace missing teeth or make special appliances called "speech bulbs" or "palatal lifts" to help close the nose from the mouth so that speech sounds more normal. The prosthodontist coordinates treatment with the oral or plastic surgeon and with the speech pathologist.
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