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.