Table 4.

Association between the genotype at claudin-14 and calcium excretion in 24-hour urine (n=393) and 2-hour urine collected during sodium chloride infusion (n=370)

VariablesHomozygotes for the Minor AlleleHeterozygotesHomozygotes for the Major AlleleP Value
rs219739 (C>T) in block A calcium excretion, mg/24 h178±85 (n=28)191±108a (n=151)222±121 (n=214)<0.01
 calcium excretion during NaCl infusion, mg/2 h22±14 (n=26)28±21 (n=144) 30±18 (n=200) 0.03
rs9636632 (A>G), no block calcium excretion, mg/24 h174±88 (n=72)208±118a (n=191)224±120 (n=130)<0.01
 calcium excretion during NaCl infusion, mg/2 h26±18 (n=65)29±20 (n=185)31±19 (n=121)0.15
rs2835364 (G>A) in block C calcium excretion, mg/24 h87±36 (n=2)171±86a (n=63)215±118 (n=328)<0.01
 calcium excretion during NaCl infusion, mg/2 h14±8 (n=2)25±17 (n=61)30±20 (n=307)0.05
rs7277076 (T>C) in block D calcium excretion, mg/24 h164±112a (n=51)206±107 (n=198)226±123 (n=144)0.002
 calcium excretion during NaCl infusion, mg/2 h27±20 (n=48)28±16 (n=189)31±23 (n=135)0.08
21:37835184 (D>R), no block calcium excretion, mg/24 h159±110b (n=54)208±104 (n=200)224±127 (n=139)0.002
 calcium excretion during NaCl infusion, mg/2 h23±19a (n=53)29±17 (n=189)31±23 (n=128)0.02
rs219778 (A>G) in block E calcium excretion, mg/24 h142±84a (n=23)198±106 (n=127)218±120 (n=243)0.004
 calcium excretion during NaCl infusion, mg/2 h28±19 (n=23)26±15 (n=115)30±21 (n=232)0.10
rs219780 (C>T) in block E calcium excretion, mg/24 h150±77 (n=9)193±111 (n=107)214±117 (n=277)0.04
 calcium excretion during NaCl infusion, mg/2 h40±24.2 (n=9)26±15 (n=99)30±20 (n=262)0.04
  • Findings about rs219755 located in the block B are reported in Table 3. Calcium excretion in 24-hour urine and 2-hour urine collected at the end of the NaCl infusion test (intravenous infusion of 2 L of 0.9% NaCl in 120 minutes) was tested in patients with different genotypes at the single-nucleotide polymorphisms with the most significant association with calcium excretion among those of each 3′ region haplotype block of claudin-14. D is an unknown base of 21:37835184 single-nucleotide polymorphism, which is not yet codified within international databases. P value for genotype-phenotype association was estimated with linear regression. Comparison between groups was performed with one-way ANOVA and Tukey test. NaCl, sodium chloride.

  • a P<0.05 versus homozygotes for the major allele.

  • b P<0.05 versus heterozygotes and P<0.01 versus homozygotes for the major allele.