Case# A3054-21, Macedonian, Male, 5yr age of onset

CasePresentingHPOs HP:0001919, HP:0000121, HP:0000074

CasePreviousTesting 30 genes previously linked to nephrolithiasis were screened by exon sequencing in these individuals, but no causative mutations were detected

CaseMethod1 NGS

CaseGenotypingMethod list of 18 hypothetical candidate genes and performed exon amplification with consecutive next-generation sequencing in a multicenter cohort of 348 individuals with nephrolithiasis or isolated nephrocalcinosis

Variant NM_134425.2(SLC26A1):c.554C>T (p.Thr185Met), NM_022042.3(SLC26A1):c.1073C>T (p.Ser358Leu)

ClinVar 242374, 242375

gnomAD 0.0004342, 0.0005655

VariantEvidence Immunofluorescence of SLC26A1 protein, when overexpressed in HEK293 cells, showed that p.Thr185Met causes protein to fail to reach plasma membrane (Figure 2). Monitoring of intracellular pH showed that p.Thr185Met has severely reduced activity (Figure 4). PCR of slc26a1 transcript in H293K cells showed no change in amount of transcript suggesting that the low p.Ser363Leu band levels in the immunoblot (Figure 3) were due to low portein stability.

Case# B641-12, "European," Male

CasePresentingHPOs HP:0000787

CaseNotHPOs HP:0003159

CasePreviousTesting 30 genes previously linked to nephrolithiasis were screened by exon sequencing in these individuals, but no causative mutations were detected

CaseMethod1 NGS

CaseGenotypingMethod list of 18 hypothetical candidate genes and performed exon amplification with consecutive next-generation sequencing in a multicenter cohort of 348 individuals with nephrolithiasis or isolated nephrocalcinosis

Variant NM_134425.2(SLC26A1):c.166G>A (p.Ala56Thr)

ClinVar 242376

gnomAD 0.0005655

VariantEvidence Monitoring of intracellular pH in transfected HEK293 demonstrated that p.Ala56Thr had reduced anion exchange activity. (Figure 4)

CaseAddInfo homozygous, consanguineous parents