CHANGES IN THE KERATINOCYTES IN OCULO-CUTANEOUS TYROSINOSIS - RICHNER-HANHART SYNDROME

  • 1 January 1980
    • journal article
    • research article
    • Vol. 107  (11) , 1023-1030
Abstract
Richner-Hanhart syndrome corresponds to a tyrosine elevation in serum due to a defect in soluble tyrosine aminotransferase in liver cells. This new enzymopathy which was transmitted in an autosomal recessive mode was called oculocutaneous tyrosinosis. It was curable by a diet low in tyrosine and its precursors. The diagnosis was clinically suggested in an 18 mo. old girl, by the association of punctate palmar and plantar keratosis, dendritic ulcerated keratitis and mental retardation. The diagnosis was established by elevation of tyrosinemia up to 52 mg/100 ml associated with a high urinary elimination of tyrosine and phenylcetonic acid. Absence of anomaly in the metabolism of methionine and hepatorenal lesion was characteristic. The diagnosis was confirmed by the absence of soluble tyrosine aminotransferase in liver cells and the effectiveness of the diet. The clinical keratosis corresponded histologically to an orthokeratotic hyperkeratosis. The keratinocytes showed 2 types of anomalies in the epidermous. Intracytoplasmic vacuoles which included or led to pseudomyelinic formations extended progressively from mitochondrial alterations in epidemial basal layers. Bulky polyhedral electron dense particles were found in the cytoplasm of the superficial keratinocytes. Most of these images were demonstrated anteriorly in the keratinocytes and the cornea. Signs of mitochondrial anomaly were not observed. The genesis of these cellular alterations based on the liberation of lysosomal enzymes by the action of crystals of tyrosine was suggested by Goldsmith from experimental facts. The mitochondrial defect occurred outside this mechanism.