Among 227 patients with dry skin at the dermatologist visit, 18 homozygotes with 2282del4 mutation (rs138726443), aged 3 months to 72 years (11 patients with atopic dermatitis, 6 patients with ichthyosis, 3 of them with both diseases), in the pathogenesis of which this mutation plays an important role, were selected based on the results of genetic testing for three mutations in the filaggrin gene R501X (rs61816761), 2282del4 (rs558269137), R2447X (rs138726443). Analysis of individual characteristics of clinical conditions is important for personalized medicine. Therefore, this article reviews 4 clinical cases of patients homozygous for a mutation in the filaggrin gene (a 2-year-old patient with a combination of 2282del4 mutation and mutation associated with neurofibromatosis type 1, deletion of two nucleotides in exon 28 of NF1 gene; a 4-year-old patient with linear lichen; a 58-year-old patient with a combination of vulgar ichthyosis, fixed toxicoderma, pruritus, and seborrheic keratosis; and a 10-month-old patient with contact dermatitis complicated by a secondary infection in combination with atopic dermatitis). These examples draw the attention of physicians to the possible role of filaggrin gene mutation in the development of skin conditions and demonstrate the need to expand the implementation of genetic testing for this mutation in clinical practice.