Anomaly Detection ISS, Leri-Weill Syndrome And Turner Syndrome In SHOX Gene / PAR1 Region

BackgroundGrowth of human is influenced by environmental, genetic and many other factors. There are many candidate genes about growth, among which a short stature homeobox-containing gene (SHOX) plays a key role in growth development. The prevalence of SHOX mutations in individuals with ISS is around2-15%, which is around50-90%with Leri-Weill syndrome. The gene defects include deletion, duplication in SHOX gene/PAR1, missense and nonsense mutation in SHOX gene. GH is approved to apply in short stature patients with SHOX deficiency by FDA and EMEA. It is believed that the growth gain in SHOX deficiency patients is the same as Turner syndrome. It will help clinicians in therapy and prognosis with genetic diagnosis of SHOX deficiency to ISS and Leri-Weill syndrome patients. There are many methods to detect SHOX defect including FISH, microsatellite analysis, MLPA and gene sequencing, of which MLPA is most recommended. By now there are few researches on SHOX gene by MLPA in China. This research explored the relationship between short stature and SHOX gene/the sequence downstream and upstream, and made a comparison among three methods.MethodThe DNA extraction of venous blood from ISS, Leri-Weill syndrome, undiagnosed patients with SHOX gene abnormal potential, Turner syndrome, Klinefelter syndrome patients and health controls was acquired. MLPA and gene sequencing were performed using the samples mentioned above. Then a confirmation to patients with abnormal MLPA results through microsatellite analysis at CASHOX, DXYS10092and DXYS10093was achieved.Results1. Gene sequencing:in six ISS patients and two first degree relatives, there are11point mutations in five ISS patients and one relative, mutation rate is83.3%. All of them are in regulatory region. In21Turner syndrome patients and two first degree relatives, there are eight point mutations in five patients, mutation rate is23.8%. Seven of them are at regulatory region, and one is at exon3causing arginine changed to tryptophan. In eight undiagnosed patients, there are eight point mutations, mutation rate is75%. All of them are at regulatory region.2. MLPA analysis:there is no abnormal detection in Leri-Weill syndrome patients. In ISS patients, there are two duplications in PAR1and one large region deletion in X chromosome. The defect rate is33.3%. In undiagnosed patients, there are duplications in exon4-6a and PAR1in one patient, defect rate is25%. The MLPA results in five positive controls are consistent with karyotype analysis.3. Microsatellite analysis:there are21microsattlelite sites in seven patients,14are consistent with MLPA results, conformity rate is66.7%.4. There is no colinearity between the severity of short stature and number of mutation sties, the range of duplication and deletion region.ConclusionCompared to microsatellite analysis, MLPA is more sensitive in detecting SHOX gene/PARl defect. Gene sequencing should be a screening test to ISS and Leri-Weill syndrome patients. The mutation rate is higher in regulatory region than coding area, but it needs further functional research to confirm new mutation. Duplication is more frequent in SHOX gene/PARl comparing deletion, and main area is PAR1. There is potency of MLPA in detecting Turner syndrome, Klinefelter syndrome and other chromosome copy number disorder disease.