RESUMEN
<p><b>OBJECTIVE</b>To identify pathogenic mutation of the TSC1 and TSC2 genes in a patient with tuberous sclerosis.</p><p><b>METHODS</b>Peripheral venous blood samples and clinical data of a pregnant woman with tuberous sclerosis and 4 family members (parents, uncle and husband) were collected. Genomic DNA was extracted. All coding exons of the TSC1 and TSC2 genes and their flanking intronic sequences were amplified by polymerase chain reaction and subjected to direct sequencing.</p><p><b>RESULTS</b>The patient has presented facial angiofibroma and prefrons fibrous plaque for 20 years, and lumbar connective tissue nevus for 10 years. She also had mental retardation but no epilepsy. A novel frame-shift mutation c.4258-4261delTCAG was detected in exon 34 of the TSC2 gene, which had led to a premature stop codon TAG after the 55th amino acids. The same mutation was not found in the unaffected family members and 100 unrelated healthy controls.</p><p><b>CONCLUSION</b>The novel frame-shifting mutation c.4258-4261delTCAG (p.Ser1420GlyfsX55) in the TSC2 gene may be responsible for the disease in the patient.</p>