Type 2 spondyloepimetaphyseal dysplasia with joint laxity caused by KIF22 gene mutation: a case report and literature review / 中华骨科杂志

A male patient aged 1 year and 8 months with type 2 spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL2) was reported. The clinical characteristics included short stature, flat middle face, hypotonia, limb joint relaxation, hyperextension of metacarpophalangeal articulation, etc. In addition, the patient had a history of congenital laryngeal stridor. Thus, SEMDJL2 was determined according to the above symptoms and medical history. Sanger sequencing showed that the child carried a c.443C>T missense mutation in the KIF22 gene, which resulted in an amino acid variation namely p.Pro148Leu. This phenotype was preliminarily determined as a pathogenic mutation. Therefore, it is suggested that next-generation sequencing genetic testing could be helpful for genetic diagnosis in children with congenital laryngeal stridor, systemic joint relaxation, and excessive joint extension.

A Modified Extraction Method of Circulating Free DNA for Epidermal Growth Factor Receptor Mutation Analysis

PURPOSE: Circulating free DNA (cfDNA) in plasma is promising to be a surrogate for tumor tissue DNA. However, not all epidermal growth factor receptor (EGFR) mutations in tumor tissue DNA has been detected in matched cfDNA, at least partly due to inefficient cfDNA extraction method. The purpose of this study was to establish an efficient plasma cfDNA extraction protocol. MATERIALS AND METHODS: The yield of plasma cfDNA extracted by our modified phenol-chloroform (MPC) method from non-small-cell lung cancer (NSCLC) patients was compared with that by QIAamp MinElute Virus Spin kit (Qiagen kit) as control, using the Wilcoxon rank-sum test. TaqMan quantitative polymerase chain reaction (qPCR) assays were used to quantify the plasma cfDNA extracted. Both Mutant-enriched PCR (ME-PCR) coupled sequencing and DxS EGFR mutation test kit were used to evaluate the impact of extraction method on EGFR mutation analysis. RESULTS: MPC method extracted more plasma cfDNA than Qiagen kit method (p=0.011). The proportion of longer fragment (> or =202 bp) in cfDNA extracted by MPC method was significantly higher than by Qiagen kit method (p=0.002). In the sequencing maps of ME-PCR products, a higher mutant peak was observed on plasma cfDNA extracted by MPC method than by Qiagen kit method. In DxS EGFR mutation test kit results, plasma cfDNA extracted by MPC method contained more tumor-origin DNA than by Qiagen kit method. CONCLUSION: An improved plasma cfDNA extraction method of MPC is provided, which will be beneficial for EGFR mutation analysis for patients with NSCLC.