A Novel Mutation of the Calcium-Sensing Receptor Gene Causing Familial Hypocalciuric Hypercalcemia Complicates Medical Followup after Roux-en-Y Gastric Bypass: A Case Report and a Summary of Mutations Found in the Same Hospital Laboratory

Table 1

Results from biochemical analysis and measures of bone mineral density.

		I		II1	II2
CaSR mutation		+/-		+/-	-/-
		at presentation	at time for II1’s and II2’s testing	at diagnosis	at testing
Age		36	42	17	12
Biochemical analyses:	Reference:
25-hydroxy vitamin D (nmol/L)	> 50	53	40 ↓	25 ↓	24 ↓
Calcium ion, ionized (mmol/L)	1.18 – 1.32	1.47 ↑	1.46 ↑	1.45 ↑	1.15
Parathyrine (pmol/L)	1.1 – 7.1	8.9 ↑	10.9 ↑	4.2	14.1 ↑
Alkaline Phosphatase (U/L)	35 -	89	118 ↑	91	213
Calcium:Creatinine clearance ratio	> 0.010	< 0.003 ↓	not measured
Measure of bone mineral density:		Result	Result
DXA Lumbar spine (T-score)	> - 1.0	-0.6	-1.2 ↓
DXA Total hip (T-score)	> - 1.0	-0.2	0.1

For the patient (I), results are shown at presentation, as well as at the time for testing of her two daughters (II₁ and II₂) whose results at testing are shown. Apart from CaSR-gene sequencing and results from I’s presentation, all blood samples from all three patients are drawn and analyzed at the same day.
Reference range for Alkaline Phosphatase differs with age; the one for adults is shown in the table, for the girl aged 17 years reference range is 42-102, and for the girl aged 12 it is 143-396. ↑ indicates that the result is above upper reference limit. ↓ indicates that the result is below lower reference limit. +/-, heterozygous mutation in the CaSR-gene; -/-, no mutation in the CaSR-gene.