Table 1 Clinical and biochemical features of the six patients

Sex

M

F

M

F

M

M

Age of onset

3 mo

3 mo

5 days

2 mo

1 mo

1 mo

Age at diagnosis

9 mo

6 mo

1 mo

11 yr

8 mo

1 yr

Symptoms

Fever

+

Feeding difficulty

+

+

+

+

+

+

Vomiting

+

+

+

+

+

Poor weight gain

+

+

+

+

+

+

Drowsiness

+

Deep respiration

+

Polydipsia

+

Polyuria

+

Urinary tract infection

+

Constipation

+

+

+

Hypertension

+

Physical examination

Growth retardation

+

+

+

+

+

Dehydration

+

+

Hypotonia

+

+

History of vitamin D application

400-500U/d (from neonatal period to 7 mo)

Oral calcium in infancy

Vitamin D 500IU/d in neonatal period, vitamin D3 300000IU once orally at 8 mo

vitamin D 500IU/d from 1 mo to 1 yr

Family history of renal calcification

-

Mother

Father

-

Father

Grandmother

Aunt

Father

Laboratory findings

At initial presentation

Normal range

Serum Ca (mmol/L)

3.79

4.19

4.31

2.35

3.36

2.88

2.1–2.8

Serum Pi (mmol/L)

1.52

1.05

1.57

1.72

1.19

1.15

1.37–1.99

Serum Mag (mmol/L)

0.74

0.85

0.86

0.91

0.58

0.81

0.8–1.2

ALP (U/L)

260

124

178

436

154

329

143–406

PTH (pg/ml)

1.00

1.00

0.01

31.58

2

ND

10–69

25(OH)D₃ (nmol/L)

30.8

25.3

24.4

ND

> 400

77.4

≥ 50

1,25(OH)₂D₃ (pg/ml)

ND

ND

ND

110

ND

ND

Urine Ca/Cr (mmol/mmol)

1.67

ND

ND

3.19

1.35

0.24

0.00-0.20

24 h urine Ca (mmol/kg/24 h)

0.22

0.22–0.31

0.17–0.22

ND

0.21

ND

< 0.2

GFR (mL/min/1.73 m2)

84.2–127.0

42.5–94.7

45.9

89.7

66.9-136.3

104.2

< 90

At last observation

Age

2 year 6 mo

6 year 8 mo

4 mo

13 year

1 year 5 mo

1 year 5 mo

Serum Ca (mmol/L)

2.2

2.40

2.55

2.45

2.56

2.45

2.1–2.8

Serum Pi (mmol/L)

ND

1.57

1.9

ND

1.87

1.37

1.37–1.99

ALP (U/L)

ND

270

320

ND

ND

44.8

143–406

PTH (pg/ml)

ND

ND

1.2

ND

ND

ND

10–69

Urine Ca/Cr (mmol/mmol)

ND

0.09

0.44

0.16

ND

0.09

0.00-0.20

GFR (mL/min/1.73 m2)

ND

131.7

100.6

77.7

ND

137.1

< 90

Imaging examination

Nephrocalcinosis

+

+

+

+

+

+

Skeletal abnormality

-

-

+

-

+

ND

Parathyroid ultrasound

-

-

-

ND

-

ND

Gene analysis

CYP24A1 c.116G > C het

SLC34A1 c.1322 A > G het

SLC34A1 c.1697_1698insT het

CYP24A1

c.1349T > C and c.287T > A

CYP24A1

c.823T > C and c.476G > C

SLC34A1 c.1726T > C het and CYP24A1

c.376 C > T het