Analysis of clinical phenotype and gene variants in a patient with classic tuberous sclerosis complex / 中华皮肤科杂志

ABSTRACT

Objective:To analyze clinical phenotypes and pathogenic mutations of a patient with classic tuberous sclerosis complex.Methods:Clinical data was collected from a patient with classic tuberous sclerosis complex. Next-generation sequencing was performed to screen pathogenic gene variants, and Sanger sequencing to verify the mutations. Minigene plasmids were constructed and transfected into the human renal epithelial cell line 293T, and RNA was extracted for transcriptional analysis.Results:The patient clinically presented with recurrent epileptic seizures, facial angiofibroma, periungual fibroma, pulmonary lymphangioleiomyomatosis, renal angiomyolipoma and multiple osteosclerosis. Next-generation sequencing revealed a suspected pathogenic variant in the TSC2 gene in the patient. Sanger sequencing identified a heterozygous mutation c.336_336+15delGGTAAGGCCCAGGGCG in exon 4 of the TSC2 gene in the patient, but not in his parents or 100 unrelated healthy controls. Moreover, this mutation had not been previously reported. The minigene experiment showed changed mRNA sequence of the TSC2 gene in this patient with loss of the authentic splice site in exon 4 and insertion of a 74-bp intron, which shifted the splice site 90 bp downstream (r.336delins336+16_336+90) .Conclusion:The novel heterozygous mutation c.336_336+15delGGTAAGGCCCAGGGCG in exon 4 of the TSC2 gene can lead to aberrant splicing, and may contribute to tuberous sclerosis complex in this patient.