++
Genetic disorder characterized by craniofacial
anomalies, ocular hypertelorism, cleft lip and palate, epicanthal folds, and
a wide, flat nasal bridge. Affected males present cryptorchidism, bifid
scrotum, and/or hypospadias. The most significant anomalies are the presence
of cleft in the larynx and trachea, pulmonary hypoplasia, dysphagia, and
respiratory obstruction. Hypoplasia or agenesis of the corpus callosum,
kidney abnormalities, cardiac defects, and mental retardation have been
reported.
++
++
++
G Syndrome; X-Linked Opitz G/BBB Syndrome; X-Linked Opitz
Syndrome; Opitz-G Syndrome Type I; Opitz BBBG Syndrome Type I;
Hypertelorism-Hypospadias Syndrome; Telecanthus-Hypospadias Syndrome.
++
Rare; however, a number of families have been reported.
++
X-linked recessive type is based on various
defects in the midline 1 (MID1) gene located on Xp22.3, and an autosomal
dominant form with variable penetrance has been mapped to chromosome
22q11.2.
++
MID1 encodes for a protein named midin, which is
believed to play a role in anchoring the cellular microtubules that form the
cytoskeleton.
++
Based on clinical features, family history, and genetic
testing.
++
Originally described as distinct syndromes, the G
and BBB syndromes are now summarized as a single disorder characterized by
hypertelorism, hypospadias. and other midline defects. In particular,
congenital heart defects are frequent and include patent ductus arteriosus,
atrial septal defect, ventricular septal defect, coarctation of the aorta,
and complex malformations, such as tetralogy of Fallot and double-outlet
right ventricle (conotruncal anomalies). A variety of genitourinary defects
other than hypospadias, such as cryptorchidism, bifid scrotum, and
imperforate anus, also belong to the phenotypic spectrum of Opitz syndrome.
Other facial anomalies include cleft lip and palate, a broad, flat nasal
bridge, micrognathia, and up-slanting or down-slanting palpebral fissures
with epicanthal folds. Frequent anomalies are laryngeal malformation (or
cleft) and a high carina or tracheoesophageal fistula. Dysphagia associated
with recurrent aspiration is common. Achalasia of the esophagus and/or
hiatus hernia. MRI may show absent or hypoplastic corpus callosum, or
cortical atrophy with ventriculomegaly. Mild-to-moderate mental deficiency
with hypotonia.
++
Careful airway evaluation must be
performed. If time allows, consultation with an otorhinolaryngologist must
be considered to stage the laryngeal cleft. History of aspiration or the
presence of cough during swallowing must be explored during questioning.
Dysphagia is a frequent symptom, and recurrent aspirations are not uncommon.
Therefore, a chest radiograph should be routine prior to general anesthesia
in individuals at risk. Cardiac examination, including echocardiogram, must
be performed.
++
Expect difficult tracheal intubation
from facial and laryngotracheal malformations. Maintain spontaneous
ventilation until the airway has been secured and gas exchange confirmed.
Patients are at risk for aspiration during induction and recovery. May
require an endotracheal tube smaller ...