Clinical Analysis Of 35 Cases Of 21-hydroxylase-deficient Congenital Adrenal Hyperplasia

Objective We aimed to gain more insight into congenital adrenal hyperplasia(CAH)by analyzing the clinical manifestation and gene feature of children with 21-hydroxylase-deficient CAH.Methods(1).The clinical data of children with 21-hydroxylase-deficient CAH were collected,including clinical manifestations,physical signs,laboratory examinations.(2).Sanger sequencing combined with Multiplex ligationdependent probe amplification(MLPA)for exons of CYP21A2 gene were performed.(3).Treatment by glucocorticoid,Follow-up and monitor for potential complications of CAH.(4).We did statistical analysis with SPSS.Results(1).Thirty-five patients were included in our study,fifteen patients male(43%,15/35)and twenty patients female(57%,20/35).There were fifteen salt-losing types(57%,20/35),twenty simple-virilizing types(43%,15/35),and no atypical type.Vomiting and diarrhea(50%)were the most common symptoms in children with salt-losing CAH;External genital abnormality(100%)were the most common symptoms in children with simple-virilizing CAH.The average diagnostic age was 4.91±13.24 months in salt-losing CAH and56.53±38.06 months in simple virilizing type CAH,respectively.(2).All patients(100%,35/35)had elevated blood levels of 17-hydroxyprogesterone and androstenedione.31 patients(88%,31/35)had elevated progesterone.17 patients(48%,17/35)had elevated Testosterone.30 patients(90%,30/33)had elevated ACTH.17 patients(51%,17/33)had low serum cortisol.(3).Sanger sequencing combined with MLPA for exons of CYP21A2 gene were performed on 25 suspected 21-OHD patients.CYP21A2 gene mutations were detected in 23(23/25,92%)patients by the above methods.A total of thirteen types of different point mutation were detected by Sanger sequencing,including nine missense mutations(p.I173 N ? E6 cluster ?p.R357 W ?p.V282L?p.R484 P ?p.Arg436 Cys ?p.Ser494 Asn ?p.Asp184 Glu ?p.Arg357Trp),two deletion mutations(p.G111Vfs*21 ?p.L308Ffs*6),one nonsense mutation(p.Q319X)and one splice site mutation(I2G).I2G(38%)and p.I173N(14%)were the most frequent gene mutations in our study.5 cases with only one point mutation and 3 cases with no point mutations were found by Sanger sequencing.Those patients with negative results by the above methods,MLPA were performed.Three large gene deletions was detected(including exons 1 ? 3 del,exons 4 del,exons 1-7del)and 2 cases still with negative results by MLPA.(4).We have seen four 21-OHD patients complicating central precocious puberty(CPP)at the ages of 6.61 ± 1.14 years,who had the diagnosis of21-OHD made at the ages of 4.4±2.31 years,and their bone age was 11.25±0.5years.Conclusions(1).Vomiting and Diarrhea are the most common reasons of attending hospital of 21-OHD patients,which are also the common risk factors of adrenalcrisis and lead to diagnosis delayed easily for its nonspecific.(2).The sensitivity of steroid hormones for diagnosing 21-OHD ranked from great to small as follows:17-OHP=Androstenedione >Progesterone>cortisol>Testosterone.(3).Belatedly diagnosed or irregular treatment for 21-OHD may be a important cause of Central precocious puberty complicated by 21-OHD.Central precocious puberty can be observed particularly in patients with a bone age of11-12 yeras.(4).Sanger sequence combined with MLPA analysis is a reliable,quick,convenient method for detect CYP21A2 gene,which could detect both gene point mutations and large gene deletions.CYP21A2 gene mutations were detected in 92% in our study by the above methods.