Caused by an inborn error of tryptophan metabolism. Clinical signs include ataxia with photosensitivity, short stature and a high-vaulted forehead, mental retardation, and a narrow palate. The association with congenital heart defects must be considered (most often bicuspid aortic valve malformation).
Unsure but could be autosomal recessive.
Diagnosis is clinical and biochemical. Low serum tryptophan levels with normal 5-hydroxytryptophan pathways, low urinary N-methyl nicotinamide levels, and absent 5-hydroxyanthranilic acid are observed. The response to tryptophan loading is abnormal, with low-to-absent level of 3-hydroxyanthranilic acid. Monochromator studies show abnormal photosensitivity.
The main features of the disease are a short stature, cerebellar-like ataxia associated with intention tremor of the upper limb, photosensitivity of the face and trunk, and mental retardation. Other common findings are clinodactyly, high arched palate, pseudohypertrophy of the calf, and bicuspid aortic valve malformation.
Precautions before anesthesia
Obtain an ECG and an echocardiogram if a cardiac valve lesion is suspected. Proper preoperative evaluation of the airway is essential due to the presence of potential difficult instrumentation of the upper airway during laryngoscopy.
Because of the high arched palate and small maxilla, insertion of a laryngoscope with a curve blade may be more difficult. Spontaneous respiration may have to be maintained until the airway is secured. The presence of a cardiac heart defect (most often aortic valve) must be taken into consideration.
In the presence of a valve lesion, antibioprophylaxis may be recommended, and the management should be made accordingly.
Other condition to be considered
☞Cockayne Syndrome (Neill-Dingwall Syndrome): Complex congenital genetic disorder characterized by the association of dwarfism, deafness, microcephaly, facies similar to Progeria Syndrome, ataxia, photosensitivity and eye malformations, retinal atrophy, and renal insufficiency with premature aging and atherosclerosis.
PA: Family exhibiting cerebellar-like ataxia, photosensitivity and shortness of stature—A new inborn error of tryptophan metabolism. J R Soc Med