Analysis of a patient with tuberous sclerosis complex due to mosaicism TSC2 mutation / 中华医学遗传学杂志

OBJECTIVE@#To analyze variants of TSC1 and TSC2 genes in a Chinese patient with tuberous sclerosis complex (TSC).@*METHODS@#Peripheral blood samples were collected from the patient and her parents with informed consent. Following extraction of genomic DNA, potential variants of the TSC1 and TSC2 genes was detected by using targeted capture next-generation sequencing (NGS) and Sanger sequencing.@*RESULTS@#The patient was found to harbor a de novo mosaicism variant c.3295_3298delG (Val1100CysfsTer3) of the TSC2 gene, with the proportion of the mutant allele determined as 13.4%, which was confirmed by Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.3295_3298delG (Val1100CysfsTer3) variant was predicted to be pathogenic (PVS1+PS2+PM2).@*CONCLUSION@#The mosaicism heterozygous variant of c.3295_3298delG of the TSC2 gene, as detected by both NGS and Sanger sequencing, probably underlay the TSC2 in this patient.

A case of tuberous sclerosis complex due to a novel splicing variant of TSC2 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with tuberous sclerosis complex.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from members of his family and 100 unrelated healthy controls. The proband was subjected to next-generation sequencing, and candidate variant was confirmed by multiple ligation-dependent probe amplification (MLPA) and Sanger sequencing. Reverse transcription-PCR (RT-PCR) was carried out to determine the relative mRNA expression in the proband.@*RESULTS@#The patient was found to harbor a c.2355+1G>C splicing variant of the TSC2 gene. Sequencing of cDNA confirmed that 62 bases have been inserted into the 3' end of exon 21, which has caused a frameshift producing a truncated protein.@*CONCLUSION@#The novel splicing variant c.2355+1G>C of the TSC2 gene probably underlay the TSC in the proband. Above finding has expanded the variant spectrum of TSC2 and provided a basis for preimplantation genetic testing and/or prenatal diagnosis.

Genetic screening and prenatal diagnosis in high-risk families with tuberous sclerosis complex syndrome / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for 29 Chinese pedigrees affected with tuberous sclerosis complex (TSC) and assess efficacy of combined next generation sequencing (NGS) and multiple ligation-dependent probe amplification (MLPA) for the diagnosis.@*METHODS@#NGS and MLPA were used in conjunct to detect variants of TSC1 and TSC2 genes among the probands of the pedigrees. Paternity test was carried out to exclude maternal DNA contamination. Prenatal diagnosis was provided to 14 couples based on the discoveries in the probands.@*RESULTS@#Twenty-seven variants were identified in the TSC1 and TSC2 genes among the 29 pedigrees, which yielded a detection rate of 93.1%. Respectively, 5 (18.5%) and 22 (81.5%) variants were identified in the TSC1 and TSC2 genes. Twelve variants were unreported previously. Prenatal diagnosis showed that five fetuses were affected with TSC, whilst the remaining nine were unaffected.@*CONCLUSION@#Above finding has expanded the spectrum of TSC1 and TSC2 gene variants. Combined NGS and MLPA has enabled diagnosis of TSC with efficiency and accuracy.

Genetic analysis of a pedigree affected with tuberous sclerosis complex caused by a novel mutation of TSC1 / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype of a Chinese pedigree affected with Tuberous sclerosis complex (TSC) and explore pathogenic mutations of TSC1 and TSC2 gene.@*METHODS@#Unique clinical phenotypes，the results of imaging, examination of the proband and special family history, collectively, made the constellation of features of TSC. Genomic DNA was obtained from six affected and eight unaffected members of the family and potential mutations of the TSC1 and TSC2 genes were detected by PCR-amplification of the exons and exon-intron boundaries and direct sequencing. A total of 150 normal unrelated individuals were used as controls.@*RESULTS@#Genetic analysis documented the presence of a heterozygous mutation, c.1781_1782delTG (p.Val594GlyfsX11), in the exon 15 of TSC1 gene within all the patients of the family. This mutation was not observed in the eight unaffected family members or in the 150 unrelated control subjects from the same population , or the Human Gene Mutation Database (HGMD) and had completely co-segregated with the disease phenotype in the family.@*CONCLUSION@#The c.1781_1782delTG mutation of TSC1 gene may be responsible for the tuberous sclerosis complex in this family. The data presented in the present study are of significance to clinicians, as well as genetic counselors, and may provide new clues for molecular diagnosis of this disease．.

Genetic diagnosis of a patient with long-time misdiagnosis of epilepsy / 中华医学遗传学杂志

OBJECTIVE@#To identify pathogenic mutation of TSC1 and TSC2 genes in a patient with long-time misdiagnosis of epilepsy.@*METHODS@#Peripheral blood samples and clinical data of the patient and her 2 parents were collected. Potential mutation of TSC1 and TSC2 genes were detected by direct sequencing.@*RESULTS@#The patient had frequent episodes of epilepsy in addition with Shagreen patches for 10 years. A frame-shifting mutation c.2509_2512delAACA was detected in exon 20 of the TSC1 gene. This same mutation was not found in her unaffected parents.@*CONCLUSION@#The recurrent frame-shifting mutation c.2509_2512delAACA (p.Asn837ValfsX11) of the TSC1 gene probably underlies the disease in this patient.

Estudio clínico genético en pacientes con complejo de esclerosis tuberosa / Clinical and genetic study patients with tuberous sclerosis complex

El complejo de esclerosis tuberosa (CET) es una enfermedad autosómica dominante multisistémica producida por mutaciones en los genes supresores de tumores TSC1 o TSC2. Objetivo: Caracterizar clínica y genéticamente pacientes pediátricos con diagnóstico de CET. Pacientes y Método: Estudio descriptivo de registros clínicos de 42 pacientes pediátricos controlados en un servicio de neuropsiquiatría infantil con diagnóstico de CET y estudio genético en 21 de ellos. Se amplificó por reacción en cadena de la polimerasa y secuenció el exón 15 del gen TSC1 y los exones 33, 36 y 37 del gen TSC2. Se analizó la relación entre las mutaciones encontradas con la severidad y evolución clínica. Resultados: En el 61,9% de los pacientes las manifestaciones comenzaron antes de los 6 meses de edad. Las manifestaciones iniciales de CET más frecuentes fueron las crisis convulsivas (73,8%) y el hallazgo de rabdomiomas cardiacos (16,6%). Durante su evolución, todos los pacientes presentaron compromiso neurológico; el 92,9% presentó epilepsia. Todos los pacientes presentaron máculas hipomelanóticas, 47,6% pangiofibromas faciales, 23,8% parches de Shagreen, 47,6% rabdomiomas cardiacos y 35,7% hamartomas retinianos. El estudio genético realizado a 21 pacientes identificó 2 mutaciones heterocigotas patogénicas en TSC1 y una en TSC2. Este último paciente presentaba un fenotipo clínico más severo. Conclusiones: Las manifestaciones neurológicas y dermatológicas fueron las más frecuentes en los pacientes con CET. Se identificaron 2 mutaciones patogénicas en el gen TSC1 y una en el gen TSC2. La mutación en TSC2 se manifestó en un fenotipo clínico más severo.

Tuberous sclerosis complex (TSC) is a multisystem autosomal dominant disease caused by mutations in the tumor suppressor genes TSC1 or TSC2. Objective: To characterize clinically and genetically patients diagnosed with TSC. Patients and Method: Descriptive study of clinical records of 42 patients from a pediatric neuropsychiatry department diagnosed with TSC and genetic study in 21 of them. The exon 15 of TSC1 gene and exons 33, 36 and 37 of TSC2 gene were amplified by polymerase chain reaction and sequenced. The relationship between the mutations found with the severity and clinical course were analyzed. Results: In 61.9% of the patients the symptoms began before 6 months of age. The initial most frequent manifestations of TSC were new onset of seizures (73.8%) and the detection of cardiac rhabdomyomas (16.6%). During the evolution of the disease all patients had neurological involvement; 92.9% had epilepsy. All patients presented hypomelanotic spots, 47.6% facial angiofibromas, 23.8% Shagreen patch, 47.6 heart rhabdomyomas and 35.7% retinal hamartomas. In the genetic study of 21 patients two heterozygous pathogenic mutations in TSC1 and one in TSC2 genes were identified. The latter had a more severe clinical phenotype. Conclusions: Neurological and dermatological manifestations were the most frequent ones in patients with TSC. Two pathogenic mutations in TSC1 and one in TSC2 genes were identified. The patient with TSC2 mutation manifested a more severe clinical phenotype.