Objective: To investigate the clinical and molecular characteristics of a girl with aldosterone synthase deficiency type II (ASDII). We also identified the consequences of a novel splice site mutation in the CYP11B2 gene.
Materials and Methods: A4-month-old girl presented with vomiting, diarrhea, and failure to thrive. Her 17α-OHP, cortisol, renin, and aldosterone were all in the normal range, and the ACTH stimulation test suggested that the adrenal cortex responded well. Sequencing was performed using genomic DNA. An in vitro analysis was performed using a minigene splicing assay based on the pSPL3 exon trapping vector. The wild-type (pSPL3-WT) and mutant (pSPL3-Mut) plasmids, containing exon 7, intron 7, exon 8, a partial sequence of intron 6 and intron 8, were separately cloned into the pSPL3 vector. The wild-type and mutant constructs were transiently expressed in COS-7 cells. Cellular RNA was extracted for reverse transcription, and the PCR products were sequenced for further identification. Structural simulation of the two novel mutations was conducted.
Results: The mutation analysis identified one patient with compound heterozygosity [c.1342C>T/pR448C; c.1200+1G>A/p.L375Cfs*1]. The minigene construction analysis revealed that the mutation resulted in aberrant splicing, in which exons 7 and 8 were skipped, resulting in the deletion of exons 7 and 8 and the premature formation of a stop codon in exon 9.
Conclusion: We report two novel CYP11B2 mutations in a Chinese family with ASD type II. We identified one splice mutation (c.1200+1G>A/p.L375Cfs*1). The description of the metabolic phenotype of the patient is important for clinician. A genetic test is an effective diagnostic tool for rare endocrine-metabolic diseases.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology