RESUMEN
BACKGROUND: The aim of this study was to explore the source and morphology of a small supernumerary marker chromosome (sSMC) from karyotype analysis of a patient with a unique case of mosaic Turner syndrome. The study findings will provide technical reference and genetic counseling for similar cases. CASE PRESENTATION: A female patient with 46,X,+mar karyotype was diagnosed by genetic karyotype analysis. Genetic methods including fluorescence in situ hybridization (FISH) and copy number variation sequencing (CNV-seq) based on low-depth whole-genome sequencing were used to explore the source and morphology of sSMC. FISH technology showed that 56.5% of the cells were X and 43.5% of the cells were XY. CNV-seq detection found that the sSMC was chrY, implying that the patient's karyotype was mos 45,X[58.6%]/46,XY[41.4%]. Retrospective karyotype analysis indicated that the female patient's sSMC was inherited from her father's small chrY. Customized FISH probe of Yq12 microdeletion was positive, indicating that the sSMC was a del(Y)(q12). Based on the results of genetic diagnosis, the specialist doctor gave a comprehensive genetic consultation and ordered regular follow-up examinations. CONCLUSIONS: The findings of the current study showed that the chromosome description of the unique Turner case was mos 45,X[56.5%]/46,X,del(Y)(q12)[43.5%]. FISH technology played a key role in diagnosis of mosaicism. The terminal deletion of mosaic chrY provided a scientific and an accurate explanation for masculinity failure and abnormal sexual development of the current case.
RESUMEN
The voltage-gated sodium channel NaV1.7, encoded by the gene SCN9A, is located in peripheral neurons and plays an important role in epileptogenesis. Previous studies have identified an increasing number of SCN9A mutations in patients with variable epilepsy phenotypes. Phenotypes of SCN9A mutations include febrile seizures (FS), genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome (DS), which pose challenges in clinical treatment. Here, we identified a heterozygous SCN9A mutation (c.980G > A chr2:167149868 p.G327E) from two twin sisters with Rolandic epilepsy by whole-exome sequencing. The patient became seizure free with a combination of levetiracetam and clonazepam. Identification of this mutation is also helpful for advancing our understanding of the role of SCN9A in epilepsy and provides deeper insights for SCN9A mutations associated with broad clinical spectrum of seizures.
