关键词: Rothmund-Thomson综合征, 中性粒细胞减少, DNA突变分析, 皮肤表现, USB1基因, 伴中性粒细胞减少症的皮肤异色病

Abstract: 【Abstract】 A 13-year-old male patient presented with skin abnormalities for more than 10 years and slow growth in body height for more than 5 years. Since the age of 6 months, erythema and scales had occurred on the extremities, and gradually spread to the trunk and face; brown pigmentation and punctate depigmentation appeared after subsidance of the erythema and scales, accompanied by dental caries, thickened palms and soles, nail thickening and peeling. Since the age of 6 years, the patient had presented with slow growth in body height, gonadal dysgenesis, sparse eyebrows and eyelashes, flat cheekbones and lameness in walking. In the past 10 years, neutrophil count had been found to be continuously lower than the normal reference value. Blood routine examination showed a neutrophil count of 1.1 × 109/L and a neutrophil proportion of 0.345; serum level of testosterone in the patient （< 0.087 nmol/L） was lower than normal levels. DNA was extracted from the peripheral blood of the patient and his parents, and gene mutation analysis was carried out by using whole-exome sequencing technology. Genetic testing showed compound heterozygous mutations in the USB1 gene of the patient, including the c.450-2A>G mutation inherited from his mother and the c.335de1G mutation inherited from his father, and the c.335de1G mutation had not been reported in China and other countries.

Key words: Rothmund-Thomson syndrome, Neutropenia, DNA mutational analysis, Skin manifestations, USB1 gene, Poikiloderma with neutropenia