Table 1.
Baseline characteristics of nine pediatric patients with XLH.
| Patient | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Age | 5 yrs 1 mo | 5 yrs 7 mos | 6 yrs 4 mos | 9 yrs 2 mos | 9 yrs 11 mos | 11 yrs 6 mos | 13 yrs 4 mos |
| Sex | F | M | M | F | M | F | F |
| PHEX gene mutation | c.1783A>T(het); pLys595* | c.146delIT; p.His487Glnfs*28 | c.565C>T(het); pGin189X(STOP), mosaicism50% | Not done | c.488C>A(hemi); p.Ser163*(STOP) | Not done | c.1735G>A (het); p.Gly579Arg; rs875989883 |
| XLH in the nuclear family | Mother and sister | Mother | Mother and brother | ||||
| Age at diagnosis | 1 yrs 6 mos | 7 mos | 2 yrs | 2 yrs 6 mos | 2 yrs 6 mos | 6 yrs | 1 yrs |
| Height SDS | −2.14 | −2.01 | −0.19 | −1.00 | −1.40 | −2.42 | −2.07 |
| Weight SDS | −0.51 | −0.28 | 0.39 | 0 | 0.41 | 0.42 | −1.76 |
| BMI SDS | 1.31 | 1.58 | 0.84 | 0.49 | 1.34 | 1.77 | −0.91 |
| Pubertal stage, Tanner | 1 | 1 | 1 | 1 | 1 | 3 | 3 |
| Fat% (normal range) | 25.6 (15–25) | 22.4 (13–20) | 21.6 (13–20) | 23.4 (16–27) | 26.9 (13–22) | 29.7 (16–29) | 21.2 (16–29) |
| Muscle mass, kg (normal range) | 11.5 (13.3–16.8) | 13.6 (17.9–22.7) | 16.2 (22.8–28.9) | 20.7 (22.9–28.9) | 22.9 (28.1–35.6) | 28.8 (23.5–29.7) | 25.6 (28.6–36.2) |
| ASMM, kg | 3.7 | 4.0 | 5.5 | 8.1 | 8.9 | 11.2 | 10.3 |
| Muscle-to-fat ratio | 0.9 | 1.0 | 1.1 | 1.2 | 1.0 | 0.9 | 1.4 |
| Serum phosphate (mg/dl) | 2.1 | 3.7 | 3.4 | 2.2 | 2.6 | 2.6 | 2.8 |
| Serum alkaline phosphatase (U/l) | 290 | 471 | 321 | 586 | 667 | 511 | 609 |
| Serum 1,25(OH)2D (ng/ml) | 23 | – | 21 | 28 | 28.1 | 25.7 | 16 |
| Serum PTH (pg/ml) | 44.5 | 50 | 43.2 | 74.2 | 21.3 | 32 | 46.6 |
| Clinical symptoms | Leg pain, Dolichocephaly Chiari I | Leg pain and genu varum | Leg pain | Leg pain and genu varum | Leg pain | Leg pain and genu varum | Leg pain and genu varum |
| Dental findings | None | Recurrent dental abscess | None | None | Dental abscess | None | None |
Normal ranges for laboratory values: serum phosphate 3.6–5.8 mg/dl; serum alkaline phosphatase 100–350 U/l; serum 1,25(OH)2D 20–100 ng/ml; serum PTH 12–65 pg/ml.
1,25(OH)2D, 1,25-dihydroxyvitamin D; ASMM, appendicular skeletal muscle mass; BMI, body mass index; F, female; IM, intramuscular; M, male; mo, month; PTH, parathyroid hormone; rGH, recombinant growth hormone; SDS, standard deviation score; XLH, X-linked hypophosphatemia; yrs, years.