N Syndrome

At a glance

Congenital association of ocular and ear anomalies with spasticity of the limbs, mental retardation, cryptorchidism, hypospadias, and a high risk of leukemia.

Synonym

Opitz “N” Syndrome.

History

The term N Syndrome is taken from the first letter of the name of the affected family.

Incidence

Unknown. Only three cases have been reported.

Genetic inheritance

Autosomal recessive or sex-linked inheritance. It has also been suggested that the N Syndrome is X-linked recessive.

Pathophysiology

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 defect.

Diagnosis

The association of impaired hearing and visual problems with genital anomalies in a male infant should be suggestive. Laboratory investigation is useful.

Clinical aspects

Features include a long face with telorism, microretrognathia, arachnodactyly, and a short stature. The other aspects are visual impairment, sensorineural deafness, laterally overlapping upper eyelids, nystagmus, large corneas, abnormal auricles, cryptorchidism, hypospadias, and spasticity. Anodontia or oligodontia is a frequent feature. 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.

Anesthetic considerations

Spasticity may make intravenous 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 (eg, preload) will dictate the anesthetic technique. Combined to a difficult airway management and the potential for tracheobronchial extrinsic compression, it is mandatory to maintain spontaneous ventilation at all times.

Pharmacological implications

No specific pharmacological implications.

References