Table 1.

Characteristics of the Proband and Her Siblings in 2017.^*

Characteristic	Patient	Carrier Sibling†	Normal Sibling
Age (yr)	58	59	60
Sex	Female	Male	Female
Calcium (mg/dl)	9.58	9.66	9.90
Phosphate (mg/dl)	2.45	2.23	2.76
Parathyroid hormone (pg/ml)	57	42	43
25(OH)D2(ng/ml)	0.060	0.085	0.172
25(OH)D3 (ng/ml)	0.019	13.054	19.483
Total 25(OH)D (ng/ml)	0.079	13.139	19.655
24,25(OH)2D3 (ng/ml)	0.000	0.312	0.918
1,25(OH)2D2 (pg/ml)	3.6	<1.0	<1.0
1,25(OH)2D3 (pg/ml)	2.0	19.5	55.7
Total 1,25(OH)2D (pg/ml)	5.6	19.5	55.7
Free25(OH)D (pg/ml)
Measured	1.8	3.4	3.2
Calculated	<0.2	7.6	5.5
Vitamin D–binding protein (μg/ml)	<3.0	95.3	224.5

^*To convert the values for calcium to millimoles per liter, multiply by 0.250. To convert the values for phosphate to millimoles per liter, multiply by 0.3229. Clinical reference ranges are as follows: calcium, 8.9 to 10.2 mg per deciliter; phosphate, 2.5 to 4.5 mg per deciliter; parathyroid hormone, 12 to 88 pg per milliliter; total 25-hydroxyvitamin D (25[OH]D), 20 to 50 ng per milliliter; and total 1,25-dihydroxyvitamin D (1,25[OH]₂D, also known as calcitriol), 17 to 72 pg per milliliter. No clinical reference ranges are available for free 25(OH)D or for vitamin D–binding protein. 1,25(OH)₂D₂ denotes 1,25-dihydroxyvitamin D₂, 1,25(OH)₂D₃ 1,25-dihydroxyvitamin D₃, 24,25(OH)₂D₃ 24,25-dihydroxyvitamin D₃ (also known as secalciferol), 25(OH)D₂ 25-hydroxyvitamin D₂, and 25(OH)D₃ 25-hydroxyvitamin D₃ (also known as calcifediol).

^†Measurements were performed in one carrier sibling.