Clinical Data And Pedigree Genetics Of 1 Case With Xp21 Contiguous Gene Deletion Syndrome

Objective: Xp21 contiguous gene deletion syndrome is a rare disease which is easy to misdiagnose.Up to now,more than 100 cases have been reported wordwide.The purpose of this paper is to explore how to diagnose rare diseases effectively,select the right gene detection to identify the cause,and further genetic counseling to reduce the risk of reoccurrence of rare diseases.Methods: To collect the clinical data of a case with Xp21 contiguous gene deletion syndrome in our hospital,including medical history,physical examination,laboratory examination and imaging examination,as well as clinical management and follow-up.To Summarize the characteristics of the case,capture keywords,consult literatures to speculate about possible diseases and select appropriateand sensitive gene detection techniques including of PCR+DHPLC and microarray hybridization.Results: The child had a history of jaundice during the neonatal period.The blood glutamic-pyruvic transaminase and lipid was mildly elevated.The blood creatine kinase was significant increased.Metabolic acidosis and electrolyte disorder was detected by blood gas analysis.Only the genes of muscular dystrophy were screened and diagnosed as " Duchenne muscular dystrophy(DMD)".At that time,it was also considered as a genetic metabolic disease,but it was not further explored,resulting in misdiagnosis and delayed treatment.At the age of his two years,the child was first admitted to our hospital for adrenal crisis The blood of biochemical index were seem as that of his neonatal.The glycerinuria was found by urinary gas chromatography-mass spectrometry.We summarized the characteristics of the case: the child was male and admitted to our hospital for adrenal crisis.This boy combined with multiple systemic diseases such as muscular dystrophy,increased triglyceride,and delayed mental and motor development.We wanted to using the "monism" to explain all clinical problems of the patient,.Then we selectedthe keywords "DMD,adrenocortical dysfunction,and glycerinuria" to review the relevant literatures and speculate that the possible diseasewas "Xp21 contiguous gene deletion syndrome".Gene accurate diagnosis: using PCR + DHPLC analysis,the DMD,GK,and NROB1 gene abnormal were detected in child.Further familial gene validation indicated that his mother revealed the only same reduction in the number of identical copies of DMD gene exons 1 to 79,and his father did not have any deletion.The microarray comparative genomic hybridization technique identified the absence of 6.73 Mb in the short arm p21.3-p21.1 region of the X chromosome,including the NR0B1,GK,DMD,and IL1RAP1 genes.This boy was eventually diagnosed as Xp21 contiguous gene deletion syndrome.Parents had no clinical symptoms andthe mother was a heterozygote which was coincident with sex linked recessive inheritance.With the help of genetic counseling and reproductive guidance,the family gived birth to a healthy baby boy.Conclusion :1.To summarize the characteristics of cases,follow up the principle of "monism" diagnosis,consult the literatures to speculate possible diseasesand select appropriate and sensitive gene detection technology is useful to precious diagnose rare diseases.2.The genetic counseling and prenatal diagnosis is very important for precision prevention rare diseases.