Family: Education: Descriptions of Disorders
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PIERRE ROBIN SEQUENCE
PIERRE ROBIN SEQUENCE
In 1923, a French physician named Pierre Robin (ro-BAHN) described a birth
defect in which a newborn was born with an abnormally small jaw. This defect
caused the infant’s tongue to fall toward the back of the mouth, blocking the
airway. Today, Pierre Robin sequence (PRS) is known to occur in up to 1 out
of every 8,000 live births.
The main feature of PRS is an abnormally small lower jaw and a cleft of the
soft palate (see Cleft Lip
and Cleft Palate). It may occur by itself, without any other problems
or defects in the baby, or along with a collection of features that together
make up a syndrome.
What Is Pierre Robin Sequence?
PRS is called a sequence because it results from a series of events
that take place as the fetus forms in early pregnancy. These events occur in
a cascade-like fashion, one leading to the next. They stem from an initial defect
of the fetus’s lower jaw, which leads to abnormal placement of the tongue. In
turn, the displaced tongue causes clefting of the palate, or roof of the mouth.
The palate develops between 5 and 12 weeks of pregnancy. It is divided into
the hard palate, which is the frontmost, hard portion of the roof of
the mouth, and the soft palate, the softer area of tissue that lies behind
it. The hard palate forms first, starting at about 5 weeks of gestation. The
soft palate is usually completely formed by about 12 weeks. It develops from
a pair of structures called the palatine processes. These structures
begin forming in the fetus’s upper jaw, growing downward on either side of the
tongue. During this process, the face and mouth of the fetus begin to elongate
to allow room for the tongue, teeth, and gums.
Normally, the tongue begins to move down and out of the way of the palatine
processes. This allows the two palatine processes to join together—somewhat
like a zipper, meeting first in the front and proceeding toward the back—to
form the soft palate. At the same time, the soft palate joins with the hard
palate to form a single, continuous tissue structure.
In PRS, this normal process is disrupted. Because the fetus’s lower jaw is
too small, it does not have enough room for the tongue. The tongue therefore
forms farther back and higher up in the mouth than is normal. The tongue also
gets in the way of the palatine processes as they try to join together in the
back of the mouth. Because the palatine processes are not able to meet, the
soft palate cannot close. The result is a cleft of the soft palate. (This type
of cleft palate is more rounded and U-shaped than that seen in other conditions.)
This sequence of events—starting with an abnormally small jaw, which
leads to displacement of the tongue, which in its turn leads to a cleft soft
palate—together make up the clinical picture of PRS.
What Causes PRS?
PRS may result from genetic or external factors. It may be passed on from one
or both parents, either by itself or as part of a genetic syndrome, before a
baby is born. As part of a syndrome, it may be accompanied by other findings.
For example, PRS may occur as part of Stickler syndrome, which is characterized
by extreme nearsightedness and arthritis.
PRS may also be caused by external (non-genetic) factors. These causes usually
result from crowding in the mother’s uterus that interferes with the growth
of the fetus’s jaw. For example, a fetus in a multiple pregnancy (twins, triplets,
or more) may be crowded in such a way that the jaw does not have enough room
to develop properly. Large fibroids in the mother’s uterus may have a similar
effect. Finally, certain types of nervous system disorders that lead to decreased
jaw movement may cause PRS.
How Is PRS Treated?
The main concern in a baby with PRS is the tendency for the tongue to block
the airway, causing breathing problems. If not addressed, decreased breathing
can lead to respiratory distress as the baby’s lungs and other internal tissues
do not receive enough oxygen. For this reason, treatment of PRS primarily consists
of taking measures to ensure that the airway remains open. These measures may
or may not involve surgery, depending on the severity of the condition.
In most cases of PRS, there is only minor interference with breathing, and
surgery is not needed to provide an open airway. In fact, in many cases the
jaw tends to catch up in its growth, as the child becomes older. In these milder
cases, all that may be needed is care in positioning the baby. He or she may
need to be placed on the stomach to keep the tongue from falling backward in
the mouth.
Moderate cases of PRS can sometimes be treated by a temporary surgical procedure
in which the tip of the tongue is attached to the lower lip. This prevents the
tongue from falling into the back of the throat. The procedure is undone when
the lower jaw has grown enough to keep the tongue in its proper position.
An infant born with a more severe case of PRS may require a tracheostomy.
This is a temporary measure consisting of a surgical opening, or stoma,
made through the front of the neck and into the trachea (windpipe). A tube is
inserted into the stoma to provide an airway and is held in place by straps
around the neck. Breathing takes place through the stoma instead of through
the nose and mouth.
The surgical procedure that is performed to create a tracheostomy is called
tracheotomy. Usually, the tracheostomy remains in place until normal
breathing is restored—either through normal growth of the child or by additional
surgery that can be performed once the child is old enough.
The cleft palate in PRS can be repaired with surgery. The time at which this
surgery is done depends on the age and health of the child, the size of the
cleft, and other factors.
Because PRS has multiple effects on a child’s health and functioning, the condition
is best managed by a team of experts. For example, a cleft palate can affect
the ability to speak and eat, so a speech pathologist is often involved in the
child’s care. With time, a cleft palate can also make ear infections and hearing
problems more likely. These complications are best managed by ear-nose-throat
specialists and audiologists. The multiple needs of children with PRS are best
evaluated and managed by a group of experts such as these, who function together
as a Cleft and Craniofacial Team.
What About the Future?
The chances that PRS will recur in a future child depend on a number of factors.
These include whether the condition is due to genetic or non-genetic factors
and whether it has occurred alone or as part of a genetic syndrome, such as
Stickler syndrome.
When PRS occurs by itself, without any other abnormalities, other family members
may be assessed to find whether they have a milder form of the condition that
has previously gone unnoticed. This information can help determine whether the
condition is due to genetic factors.
PRS due to non-genetic factors, such as crowding inside the uterus, makes it
very unlikely to be passed on from the affected individual to his or her children
. The condition may possibly recur in additional children of the parents if
the same factors (such as large fibroids) remain in a future pregnancy. If PRS
has occurred because of genetic factors, however, the parents and the affected
child may have a risk of as high as 50% of passing the condition on to their
future offspring.
Finding Information
OMIM
261800
Finding Support
The Pierre Robin Network is made up of parents, relatives, caregivers,
adults with PRS, as well as professionals with an interest in PRS. The organization
provides information to and creates networks of families and individuals with
PRS.
The Pierre Robin Network
PO Box 3274
Quincy, IL 62305
Phone: (217) 224-7480
Fax: (217) 224-0292
Outreach families: help@pierrerobin.org
General information: info@pierrerobin.org
Web site: www.pierrerobin.org
FACES: The National Craniofacial Association assists children and adults
with craniofacial disorders resulting from disease, accident, or birth, providing
general information, contact with other families, and other helpful resources.
FACES
P.O.Box 11082
Chattanooga, TN 37401
1-800-3-FACES-3
E-mail: faces@faces-cranio.org
Web site: www.faces-cranio.org
On the Web
Aaron’s Tracheostomy Homepage (www.tracheostomy.com)
provides a wealth of information and resources for parents of a child with a
tracheostomy, including home care, detailed surgical descriptions and illustrations,
dealing with complications, and support networks.
Reading Matter
Robin P. A fall of the base of the tongue considered as a new cause of nasopharyngeal
respiratory impairment: Pierre Robin sequence, a translation. 1923 [classic
article]. Plast Reconstr Surg 1994; 93(6): 1301–3. abstract
Sadewitz V. L. Robin sequence: changes in thinking leading to changes in patient
care. Cleft Palate Craniofac J 1992; 29(3): 246–53. abstract
Shprintzen R. J. The implications of the diagnosis of Robin sequence. Cleft
Palate Craniofac J 1992; 29(3): 205–9. abstract
Author: Deborah J. Shuman
Date: November 1, 2000
Disclaimer: Links to support groups and relevant web sites do not signify
an endorsement.
© 2000 The Johns Hopkins University
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Last Updated:
12/16/03
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