Panel A: Pedigree of the AD-PHP-Ib family showing a mode of inheritance that is consistent with an autosomal recessive disorder.
Panel B: Laboratory findings. * at presentation; ** range after normalization of serum magnesium level in the index case. For conversion of metric unit to SI unit; multiple by 0.25 for Ca, 0.3229 for phosphorus and 0.18 for Mg to mmol/L, 0.102 for PTH to pmol/L.
Panel C: Analysis of the STX-16 region by multiplex PCR using primers a, b, c, and d (arrows) leading to the identification of the previously described heterozygous 3-kb microdeletion comprising exons 4–6. The shortest PCR product, which was present in the two affected family members, #1 and #3, and in unaffected carrier #2, is derived from the mutant allele and amplified by primers a and d. The 967 bp product, representing the mutant product, is amplified by primers a and b, while the 793 bp product by primers c and d represents the wild-type allele.