XX Chen, T Wu, Y Sun, TM Yuan

Abstract

A 14-day-old male infant was admitted to our neonatal unit because of feeding difficulty, dehydration and weight loss. The initial analysis showed hyponatraemia and hyperkalaemia, increased plasma adrenocorticotropic hormone (ACTH) and increased plasma 17a-hydroxyprogesterone, decreased cortisol and plasma aldosterone and increased plasma 17a-hydroxyprogesterone, thereby making the 21-hydroxylase-deficient form of congenital adrenal hyperplasia likely. Cortisone acetate and fludrocortisone treatment corrected the electrolyte abnormalities and the patient improved. But the creatine kinase, lactate dehydrogenase, and triglyceride levels continuously increased. The urinary analysis revealed grossly increased levels of glycerol. At that point, chromosome Xp21 contiguous gene deletion syndrome was suspected. Further Multiplex Ligation-Dependent Probe Amplification analysis revealed both DAX1 gene and all of the 79 exons of DMD gene were deleted in the boy's blood sample. Chromosome Microarray revealed an approximately 6.3 MB deletion on chromosome Xp21.3p21.1, including DAX1, GK, DMD and IL1RAPL1 in the maternal sample. So the newborn was diagnosed as Xp21 contiguous gene deletion syndrome and his mother was a carrier.

一名14天大的男嬰因餵養困難、脫水和體重減輕在我院新生兒科接受治療。初步分析顯示存在低鈉血症、高鉀血症、血清促腎上腺皮質激素（ACTH）增高、17a-羥孕酮增高、皮質醇和醛固酮降低，因此表現類似21-羥化酶缺乏性先天性腎上腺皮質增生症。醋酸可的松和氟氫可的松可糾正電解質紊亂及改善患兒一般情況。但肌酸激酶、乳酸脫氫酶和甘油三酯水平持續升高。尿液分析顯示甘油水平明顯升高。因此懷疑是Xp21鄰近基因缺失綜合徵。取患兒血樣進一步探針擴增（MLPA）分析顯示2個DAX1基因和所有DMD基因的79個外顯子均缺失，母親血樣染色體微陣列（CMA）顯示染色體Xp21.3p21.1缺失大約6.3 MB，包括DAX1，GK，DMD和IL1RAPL1。所以該新生兒確診Xp21鄰近基因缺失綜合徵，母親為攜帶者。