Cleft lip and cleft palate are facial and oral malformations
that occur very early in pregnancy, while the baby is developing
inside its mother. A cleft results when there is not enough tissue
in the mouth or lip area, and the tissue that is available does not
join together properly.
A cleft lip is a physical split or separation of the two sides
of the upper lip and appears as a narrow opening or gap in the skin
of the upper lip. This separation often extends beyond the base of
the nose and includes the bones of the upper jaw and/or upper
gum.
A cleft palate is a split or opening in the roof of the mouth. A
cleft palate can involve the hard palate (the bony front portion of
the roof of the mouth) and/or the soft palate (the soft back
portion of the roof of the mouth).
Cleft lip and cleft palate can occur on one or both sides of the
mouth. Because the lip and the palate develop separately, it is
possible to have a cleft lip without a cleft palate, a cleft palate
without a cleft lip, or both a cleft lip and cleft palate
together.
Who gets cleft lip and/or cleft palate?
Cleft lip,
with or without cleft palate, affects one in 700 babies annually,
and is the fourth most common birth defect in the U.S. Clefts occur
more often in children of Asian, Latino, or Native American
descent. Compared with girls, twice as many boys have a cleft lip,
both with and without a cleft palate. However, compared with boys,
twice as many girls have cleft palate without a cleft lip.
What causes a cleft lip and cleft palate?
In most
cases, the cause of cleft lip and cleft palate is not known and
these conditions cannot be prevented. Most scientists believe
clefts are due to a combination of genetic and environmental
factors. There appears to be a greater chance of clefting in a
newborn if a sibling, parent, or relative has had the problem.
Another potential cause may be related to a medication a mother may
have taken during her pregnancy. Some antiseizure/anticonvulsant
medications, acne treatment medications containing Accutane, or
methotrexate, a drug commonly used for treating cancer, arthritis,
and psoriasis, may cause cleft lip and/or cleft palate.
The condition may also occur as a result of exposure to viruses
or chemicals while the baby is in the womb. In other situations,
cleft lip and cleft palate may be part of another medical
condition, such as Pierre Robin Malformation Sequence, Amniotic
Banding (also called Constriction Band Syndrome), Hemifacial
Microsomia/Goldenhar Syndrome, or Tessier Facial Clefts, among
others.