Context: Russell-Silver syndrome (RSS), characterized by intrauterine and postnatal growth retardation, dysmorphic features, and frequent body asymmetry, spares cranial growth. Maternal uniparental disomy for chromosome 7 (mUPD7) is found in 5–10% of cases. We identified loss of methylation (LOM) of 11p15 Imprinting Center Region 1 (ICR1) domain (including IGF-II) as a mechanism leading to RSS. Objective: The aim was to screen for 11p15 epimutation and mUPD7 in RSS and non-RSS small-for-gestational-age (SGA) patients and identify epigenetic-phenotypic correlations. Studied Population and Methods: A total of 127 SGA patients were analyzed. Clinical diagnosis of RSS was established when the criterion of being SGA was associated with at least three of five criteria: postnatal growth retardation, relative macrocephaly, prominent forehead, body asymmetry, and feeding difficulties. Serum IGF-II was evaluated for 82 patients. Results: Of the 127 SGA patients, 58 were diagnosed with RSS; 37 of these (63.8%) displayed partial LOM of the 11p15 ICR1 domain, and three (5.2%) had mUPD7. No molecular abnormalities were found in the non-RSS SGA group (n = 69). Birth weight, birth length, and postnatal body mass index (BMI) were lower in the abnormal 11p15 RSS group (ab-ICR1-RSS) than in the normal 11p15 RSS group [−3.4 vs.−2.6 sd score (SDS), −4.4 vs.−3.4 SDS, and −2.5 vs.−1.6 SDS, respectively; P < 0.05]. Among RSS patients, prominent forehead, relative macrocephaly, body asymmetry, and low BMI were significantly associated with ICR1 LOM. All ab-ICR1-RSS patients had at least four of five criteria of the scoring system. Postnatal IGF-II levels were within normal values. Conclusion: The 11p15 ICR1 epimutation is a major, specific cause of RSS exhibiting failure to thrive. We propose a clinical scoring system (including a BMI < −2 SDS), highly predictive of 11p15 ICR1 LOM, for the diagnosis of RSS.

Hydrated boehmite with nano-sized crystallites AlO(OH)·0.8H₂O are obtained through a very reproducible sol–gel procedure and characterized using powder X-ray diffraction, in-situ IR spectroscopy, thermal analysis, BET surface area and photoelectron spectroscopy. The unit cell parameters, obtained after deleting the first shifted (020) diffraction peak, are a = 3.686 Å, b = 12.179 Å and c = 2.855 Å. They are consistent with well-crystallized boehmite and with the position of the harmonic (080) diffraction peak. For the (020) peak, the correlation between position and peak width is confirmed for nano-crystallites. The average shape of the crystallites, determined from three peak widths, corresponds to slabs with dimensions 7.9 × 2.7 × 8.7 nm. Based on this crystallite shape, a model of hydrated boehmite is proposed and the formula corresponding to a full monolayer of chemically adsorbed water molecules is AlO(OH)·0.55H₂O. The thermal evolution of hydrated boehmite leads first to hydrated γ-alumina Al₂O₃·0.33H₂O = Al₂O_2.67(OH)_0.66 and the number of remaining hydroxyl groups is critical for the porosity. Between Al₂O₃·0.33H₂O and Al₂O₃·0.2H₂O the surface area remains approximately constant (300 m² g⁻¹) and the hydroxyl density decreases deeply. For calcination temperature higher than 800 K, the loss of the remainder of the water leads to a strong decrease of this area. The limiting value corresponds to about 9–10 OH-groups nm⁻² and can be related to the hydrogen spinel HAl₅O₈. The same type of isolated OH groups are present on hydrated boehmite and hydrated transition alumina (IR bands at 3670 and 3730 cm⁻¹). A simple model of partial dehydroxylation of boehmite is proposed, in agreement with the remaining water and unit cell parameters.