Congenital association of ocular and ear anomalies
with spasticity of the limbs, mental retardation, cryptorchidism,
hypospadias, and a high risk of leukemia.
The term N Syndrome is taken from the first letter of the name of
the affected family.
Autosomal recessive or sex-linked inheritance.
It has also been suggested that the N syndrome is X-linked
It has been suggested that N syndrome is caused by
a mutation affecting the region of the X chromosome (Xp22-3 p21-1) where
the gene for DNA polymerase alpha is located. The high risk of
T-cell leukemia observed in the hemizygote is a result of this DNA repair
The association of impaired hearing and visual problems
with genital anomalies in a male infant should be suggestive. Laboratory
investigation is useful.
Features include a long face with telorism,
microretrognathia, arachnodactyly, and a short stature. Visual impairment,
sensorineural deafness, laterally overlapping upper eyelids, nystagmus, large
corneas, abnormal auricles, cryptorchidism, hypospadias, and spasticity. Anodontia
or oligodontia are frequent features. Multiple pigmented nevi can be observed.
Sometimes the patient presents with abnormal vertebrae and moderate-to-severe mental
retardation. Patients may develop lymphoblastic leukemia with a mediastinal mass and
leukemic infiltration of tissues.
Precautions before Anesthesia
Check teeth and dental care. The
presence of a parent at induction and in the recovery room might be helpful,
considering the child's handicaps with communication. An anesthesiology
consultation is highly recommended for elective surgery. A CT Scan and
echocardiogram must be obtained to eliminate the presence of a mediastinal mass.
Spasticity may make IV line placement
difficult. It may also interfere during direct laryngoscopy and tracheal intubation. In
case of microretrognathia, alternative methods for tracheal intubation may be
necessary and should be readily available. The presence of a mediastinal mass
affecting the cardiovascular function (e.g., preload) will dictate the anesthetic
technique. Combined to a difficult airway management and the potential for
compression, it is mandatory to maintain spontaneous ventilation at all times.
No specific pharmacological
Floy KM, Hess RO, Meisner LF: DNA polymerase alpha defect in the N
syndrome. Am J Med Genet
Hess RO, Hafez G-R, Meisner LF: Updating the N syndrome: Occurrence of
lymphoid malignancy and possible association with an increased rate of
chromosome breakage. Am J Med Genet Suppl
Hess RO, Kaveggia EG, Opitz JM: The ...