Abstract
Nephrocalcinosis is a characteristic feature of both type 1 and type 2 Bartter syndrome. Bartter syndrome type 2 presents antenatally and very early in life. Late-onset presentation with isolated nephrocalcinosis is extremely rare. We describe an 11-year-old girl with incidentally detected medullary nephrocalcinosis on renal ultrasonography. She was clinically suspected to have primary hyperoxaluria based on high urine oxalate. However, clinical exome sequencing revealed a pathogenic missense variant in the KCNJ1 gene leading to the molecular diagnosis of Bartter syndrome type 2. Both parents were heterozygous carriers of the same variant. Subsequent investigations did reveal a mild Bartter syndrome phenotype with mild metabolic alkalosis, high urine chloride and high renin and aldosterone. Our case illustrates phenotypic heterogeneity of Bartter syndrome type 2 and the usefulness of genetic testing in establishing the correct diagnosis and guiding further management in such cases.
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AS conceptualized the manuscript, collected clinical information and wrote the manuscript. PP did the exome sequencing, interpreted the information, produced the report and helped in writing the manuscript. KV helped in collecting clinical data and helped in writing the manuscript. SK collected the data and helped in writing the manuscript. HP corrected the manuscript. AS will act as guaranter of the article.
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Saha, A., Pande, P., Vala, K. et al. Clinical exome sequencing uncovers an unsuspected diagnosis of Bartter syndrome type 2 in a child with incidentally detected nephrocalcinosis. CEN Case Rep 11, 417–421 (2022). https://doi.org/10.1007/s13730-022-00694-2
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DOI: https://doi.org/10.1007/s13730-022-00694-2