We report a 6-month-old Japanese boy showing ichthyosis linearis circumflexa localized on the palms and soles. He showed bamboo hairs and aminoaciduria, and was positive for cow's milk and egg IgE antibodies by radioallergosorbent tests. Trypsin-like hydrolytic activity in the patient's lesional stratum corneum showed an activity seven times higher than that in age-matched controls. DNA analysis showed that the patient harboured the compound heterozygous mutations R790X and 1220+1 G-->C in the SPINK5 gene, compatible with the diagnosis of Netherton syndrome (NS). As the genotype/phenotype correlations in NS have not yet been fully clarified, the position of the premature termination codon in the SPINK5 gene may contribute to explain such a mild form of NS in our patient.