Parents' Description of Opitz G/BBB Syndrome
Opitz G/BBB syndrome, Opitz syndrome, G syndrome,
BBB syndrome,
Opitz BBB/G syndrome, Hypospadias-Dysphagia syndrome, Opitz-Frias
syndrome, Oculogenitolaryngeal syndrome, and Hypertelorism-Hypospadias
syndrome are all names for the same condition. With this syndrome there
can be different manifestations in individuals, even within the same
family.
This genetic syndrome includes a variety of
midline and bilateral anomalies. A genetic syndrome is an hereditary condition
caused by the genes of the family and ancestors of the affected child.
It is not caused by something the mother did, or did not do, while pregnant.
When an individual has a genetic syndrome they have manifestations, or anomalies,
that are similar to other individuals who
have the same syndrome. An anomaly is anything this is differently formed. The
degree of involvement among individuals, even within the same family, can vary
greatly. Opitz G/BBB syndrome is considered “uncommon.” The number of
affected individuals is unknown as the syndrome is not always accurately
diagnosed. With careful medical treatment it is possible for individuals who
have Opitz G/BBB syndrome to live long lives.
In 1969 Dr. Opitz and colleagues described two syndromes. Each was named for the
surnames, or last names, of the families in whom they were first discovered. The
G syndrome (G) was described by John Opitz,
Jaime Frias, James Gutenberger, and John Pellet. It was named for one family
whose last name began with the initial G. The BBB syndrome (BBB) was described
by John Opitz, Robert Summitt, and David Smith. In BBB
syndrome (BBB) the three initials stood for three separate families in whom it
was discovered. At that time the two syndromes were believed to be separate
syndromes. Research in 1995 established that the genes
which determine this syndrome are located on both Xp22 (the X chromosome) and on
22q (chromosome 22). This means the syndrome can be either X-linked recessive on
Xp22, or it can have an autosomal dominant
pattern of inheritance on 22q. Only males have the form on Xp22. In the case of
being on 22q both males and females can manifest and transmit the
characteristics to sons and daughters. It was determined through this research
that the two syndromes, once thought to be separate, are one and the same
syndrome with differing manifestations in individuals, even within the same
family. The names G and BBB were combined. Most often now this condition is
called Opitz G/BBB syndrome. Ongoing research hopes to find a blood test to
determine
carriers of the defective gene. The specific genes on the chromosomes are being
mapped. A highly specialized laboratory test is not yet available, but will be
in the near future. At this point the most reliable way to diagnose Opitz G/BBB
syndrome is through a clinical evaluation made by a highly skilled, board
certified geneticist who is familiar with this particular syndrome. There are
other syndromes associated with the name of Dr. John M. Opitz. They are
different syndromes sharing the name of one busy geneticist.
Opitz G/BBB syndrome includes a variety of midline and bilateral anomalies, or
birth defects. This means that structures along a midline (an imaginary line
going down through the middle of the body) or two
structures which match on each side of the body, can be affected. Most
frequently these include wide-set eyes and other features (hypertelorism), an
abnormal opening in the penis in males (hypospadias), mild to severe swallowing
defects (dysphagia), an abnormality of the anal opening, undescended testes (cryptorchidism),
and a variety of clefts (a fissure, or split in the lip, palate, uvula,
esophagus, larynx or trachea). The fibrous band of tissue in the brain that
interconnects the two hemispheres may never have formed before birth (agenesis
of the corpus callosum, or ACC).
Affected individuals have a distinctive facial
appearance. The head (skull) may be out of proportion or asymmetrical. The skull
may grow slowly. Some have large heads, while others have small heads. The
hairline may come to a point in the front on the forehead ("widow's peak").
In addition to wide-set eyes and clefts, there may also be skin folds (epicanthic)
on the inside corners of the eyes. The eyes may be
crossed (strabismus). There may be some problems with the tear ducts. The ears
may be small and/or low-set and may be rotated slightly backward. The outside of
the ears (auricles) may be shaped differently.
Children with Opitz G/BBB syndrome often have small ear canals. Often the
sinuses are malformed. There may be a flat nasal bridge. The nose may be wide
and may have small and upturned nostrils. The mouth could
have clefts or a thin upper lip. Inside the mouth there may be a high palate.
The bottom of the tongue may be attached too closely to the gum (short lingual
frenulum). The teeth may be crowded or have abnormal
placement. Some teeth may be missing. There may be a small chin or lower jaw.
Individuals who have Opitz G/BBB may have swallowingdifficulties. This is called
"dysphagia" and may involve the voice (larynx), windpipe (trachea),
and throat (esophagus) which leads to the stomach. Many children with dysphagia
cannot swallow safely. They may not use their tongues or chew properly. Food may
go into the windpipe instead of the esophagus. This is called choking, or
aspirating. Aspiration can cause damage to the lungs and pneumonia. It can
prevent oxygen from reaching the brain and may be responsible for mental
deficiencies. It is important to prevent aspirations as death may occur in
severely affected infants either at birth or in early infancy. There may be a
small stomach. Some have reflux or acholasia where
stomach contents go back up into the esophagus and then to the lungs. Another
problem which can also be involved in the throat is the windpipe, or trachea,
itself. Individuals may have what is called tracheomalacia. The trachea can be
"soft" and not able to hold itself open fully. It can collapse when
the individual breathes. The person may have a wheezing, hoarse, or weak voice.
Some individuals sound like they are snoring. This is called “stridor” and
can be mistaken for asthma. (Individuals who have hypotonia and who also have
tracheomalacia need to use an incredible amount of energy to breathe.) Some have
webs connecting the trachea and esophagus, and some have clefts (openings) of
the esophagus leading into the trachea. Often
infants who have Opitz G/BBB are small and diagnosed as "failure to thrive."
They gain weight slowly.
The chest may be caved in (pectus excavatum) or pointed out (pectus carinatum).
The body may have a variety of hernias. There can be a variety of congenital
heart and kidney defects. Skin may be dry and have some abnormal pigmentation,
birthmarks or moles. Boys may have an abnormal opening in the penis (hypospadias),
undescended testes (cryptorchidism) and chordee. Girls may have abnormal
genitalia (splayed labia majora). Both boys and girls may have a malformation of
the anal opening and sometimes imperforate anus. There may be a deep hole at the
tip of the tailbone above the buttocks (sacral dimple). Often there is
constipation. Some defects of the skeletal/muscular system include backbone (vertebral)
anomalies. Many individuals have a crocked backbone, a condition called
scoliosis. There may be a short neck. The sternum may be affected. Feet may be
flat with crowded toes. Toes and fingers may be a different size or shape, be a
bent, or "crowded." Hands may have a single transverse flexion crease
in one or both hands. Reduced muscle tone is common, often referred to as
congenital or cerebral hypotonia.
There may be some central nervous system defects. There may be sensorineural
deafness. Mild mental deficiency is seen in many cases and may be complicated by
aspirations due to dysphagia. The brain can become damaged without oxygen when
the individual is aspirating. Some individuals have seizures and some display
some autistic-like behaviors. There are often delays in speech and physical (psychomotor)
skills.
Families also frequently report:
a variety of seizures
autistic-like behaviors
oral defensiveness
scoliosis as a complication of hypotonia
frequent ear, sinus or adenoid infections
human growth deficiency
ambiguous genitalia
mild to severe constipation
behavioral challenges
learning disabilities
