LAUSR

EJD, vol. 29, n◦ 2, March-April 2019 the 2B domain of K10 [9]. Tyrosine (Y) is a hydrophobic, non-charged, neutral amino acid and aspartic acid (D) is a hydrophilic, non-charged acidic amino acid. The substitution from Y to D can result in the loss of the hydrophobic interaction with I479 in K1 [9]. In contrast, the substitution from Y to cysteine (C; a hydrophilic neutral amino acid) has no effect on the hydrophobic interaction [9]. One EI case in which p.Y449H was detected in K10 has been reported, however, no clinical or histological findings were provided [10]. The clinical and histological findings of the present patient were more severe than those of the patient with p.Y449D. Histidine is a hydrophilic, positively charged basic amino acid; these characteristics may strongly destabilize the K1/K10 heterodimer, resulting in a severe phenotype of EI. Further research is required to clarify the genotype-phenotype correlation in EI, however, the present case helps in expanding our knowledge of EI.