Richner–Hanhart Syndrome

  • Hepatic tyrosine aminotransferase gene mutation
  • Autosomal recessive inheritance
  • Rare

  • Altered tyrosine metabolism

  • Photophobia, dendritic keratitis, corneal ulcerations within 1st year
  • Tender focal palmoplantar hyperkeratotic plaques, blistering, hyperhidrosis
  • Intellectual disability without therapeutic dietary restriction

  • Tyrosine crystal deposition on slit-lamp examination
  • Elevated serum and urinary tyrosine 

Pathology: 

  • Comparable to pachyonychia congenita
  • Needle shaped tyrosine inclusions in keratinocytes

  • Tyrosine and phenylalanine dietary restriction to resolve keratitis, keratoderma with potential prevention of cognitive disability