Artemis Doulgeraki

Sclerostin distribution in children and adolescents with type 1 diabetes mellitus and correlation with bone metabolism and bone mineral density

Sclerostin is an inhibitor of the Wnt/beta‐catenin bone metabolic pathway. Increased sclerostin levels and reduced bone mineral density (BMD) have been documented in adult patients with diabetes mellitus (DM), predominantly in those with type 2 diabetes mellitus (T2DM). No relative data exist on childhood type 1 diabetes mellitus (T1DM). Our objective was to study plasma sclerostin in T1DM children and adolescents and controls and its correlations with metabolic bone markers and BMD.

Body Composition Profile of Young Patients With Phenylketonuria and Mild Hyperphenylalaninemia

Background: There is evidence in support of low bone density in young patients with disorders of phenylalanine metabolism; however, little is known about muscle and fat mass in these patients, especially in those with mild hyperphenylalaninemia (mHPA). Objectives: We aimed to evaluate body composition of children and adolescents with early-diagnosed disorders of phenylalanine metabolism. Patients and Methods: The study was conducted in the Institute of Child Health, which is the national center that performs newborn screening. Bone, muscle, and fat mass of 48 patients with phenylketonuria (PKU) and 32 patients with mild mHPA, aged five to 18 years, were compared to 57 age- and sex-matched controls. Dual energy X-ray absorptiometry was used for this purpose. Results: Compared to controls, bone mineral density (BMD) was lower in patients with PKU (mean total body BMD z score, 0.11; P = 0.03) and in those with mild mHPA (mean lumbar BMD z score, -0.34; P = 0.01). Lean body mass and fat mass were not significantly affected in the study group. Comparison between the two patients groups did not reveal any difference in body composition profiles; however, pubertal status appeared important for within-group comparisons. Fat mass was significantly increased in teenagers with PKU, which was more evident in those with poor dietary compliance irrespective of gender (fat mass z score, 0.66; P = 0.018). Finally, positive correlations were found not only between bone, muscle, and fat mass in both groups, but also between fat mass and Phenylalanine levels in patients with PKU (r, 0.46; P = 0.001). Conclusions: Bone mineral density appears suboptimal in young patients with disorders of phenylalanine metabolism. Adolescents seemed more prone to obesity, especially when their dietary adherence was poor, whereas muscle mass was not considerably affected. To ensure healthier bones and less fat content, close follow-up as well as proper lifestyle advice is needed.

Bone health assessment of food allergic children on restrictive diets: a practical guide

Abstract Background: Food allergy in childhood is on the rise globally and is managed with avoidance diets; recent case reports of food allergic children with nutritional rickets in the literature highlight the importance of close monitoring of bone health in this population. Methods: There is no consensus as yet with regard to bone health evaluation in food allergic children; therefore, extensive literature search was performed and the existing evidence is presented, along with a relevant algorithm. Results: Children allergic to cow’s milk protein or presenting with allergy in more than three food items, as well as patients with severe allergic phenotypes or comorbidities known to affect the skeleton, seem to be at risk of metabolic bone disorders. As a practical guide, suspicious cases can be investigated with basic bone profile, whereas more severe cases (persistent bone pain and fractures) may undergo advanced bone health assessment, with bone mineral density (BMD) and metabolic bone markers’ evaluation. Of note, these diagnostic steps call for further studies in the field of food allergy, as they are not performed as a routine. Evidence is accumulating with regard to vitamin D deficiency, osteopenia and imbalanced bone metabolism in those food allergic children who show poor dietary compliance or have inadequate medical supervision. Conclusions: Ensuring optimal bone accrual in a food allergic child is an important task for the clinician and requires close monitoring of the restrictive diet and prompt therapeutic intervention, in an effort to avoid rickets or osteopenia.

Bone health evaluation of children and adolescents with homozygous β-thalassemia: implications for practice.

Objective: Bone tissue is adversely affected in patients with homozygous &bgr;-thalassemia. The aim of this study was to find warning signs of bone loss in young patients with &bgr;-thalassemia and allow prompt therapeutic interventions. Methods: Thirty-eight patients were studied, 20 boys and 18 girls, aged 5 to 18 years (median=14.13 y), on regular transfusions and chelation treatments. Their bone mineral density (BMD) was measured with dual x-ray absorptiometry. The recorded parameters were weight, height, bone age (BA), transfusion adequacy (mean fetal hemoglobin value), and chelation efficacy (mean ferritin value, compliance). Tanner stage was also evaluated: 8 prepubertal subjects (stage 1), 18 peripubertal subjects (stages 2 and 3), and 12 postpubertal patients (stages 4 and 5). Blood and urine samples were collected for biochemical analysis. Results: Mean BMD z score was −1.56±1.25. Thirteen patients had normal BMD (z score >−1), 17 patients had low BMD (z score: −1 up to −2.4), and 8 patients had very low BMD (z score <−2.5). Low BMD was observed in patients older than 12 years and was associated with short stature (r=0.33, P=0.04), delayed BA (r=0.61, P=0.01), and increased bone formation markers. There was no correlation of BMD z score with sex, fetal hemoglobin value, ferritin, and compliance. Regarding Tanner stage, it was associated strongly with short stature (r=0.57, P=0.01), ferritin (r=−0.38, P=0.02), and compliance (r=0.58, P=0.01). Conlusions: The decline in BMD may start early, even in the well-transfused patients. This study targets the young patients who are mostly at the risk for bone loss, that is short adolescents with delayed BA. Their prompt recognition in everyday practice is important, as they will need close monitoring of their BMD and metabolic bone profile. In addition, therapeutic interventions, such as adequate calcium intake and sunlight exposure, weight-bearing exercise and, in cases of vitamin D insufficiency, proper supplementation could be suggested.

Body composition in young patients with galactose metabolic disorders: a preliminary report.

Abstract Aim: Body composition evaluation in patients with galactosemia and its variants. Methods: The body composition of young subjects with galactose metabolic disorders was analyzed with dual X-ray absorptiometry. The subjects were divided into the classic galactosemia (CG; n=14) group and the group with other galactose metabolic disorders (OGMD, e.g., epimerase deficiency; n=8). Results: In both groups, bone strength and bone mineral density Z-scores were normal. However, CG patients appeared sarcopenic (median muscle mass Z-score=–1.93), whereas OGMD subjects had low-normal muscle mass. In addition, approximately half of all patients were overweight. In CG patients, bone mass was strongly correlated to muscle mass (r=0.81), whereas in OGMD patients it was positively correlated to body mass index (r=0.78). Conclusions: An imbalance between muscle and fat mass, especially in patients with classic galactosemia, was observed. Given the observed strong correlation between bone and muscle mass, more effective lifestyle counseling is needed.

Identification of a Novel Nonsense Mutation in the Ligand-Binding Domain of the Vitamin D Receptor Gene and Clinical Description of Two Greek Patients with Hereditary Vitamin D-Resistant Rickets and Alopecia

Background/Aims: We analyzed the vitamin D receptor (VDR) gene in 2 Greek patients who exhibited the classical features of hereditary vitamin D-resistant rickets (HVDRR) type II, including severe bone deformities and alopecia. We also describe the clinical phenotypes and the response to treatment of our patients. Methods: Genomic DNA was extracted from peripheral blood samples of both patients. Coding region and flanking introns of VDR gDNA was amplified and direct sequenced. Results: A unique cytosine to thymine (C>T) transition was identified at nucleotide position 1066 (c.1066C>T) in the ligand-binding domain of the VDR gene of both patients, predicting the substitution of a glutamine to a terminal codon at position 356 (Gln356stop). Conclusions: The novel nonsense mutation c.1066C>T (Gln356stop) is expected to result in a VDR protein 71 amino acids shorter and thus to affect the normal VDR function. In particular, the missing protein part alters the VDR heterodimerization with the retinoid X receptor which has been correlated with the presence of alopecia. Both patients were introduced to treatment with supraphysiological doses of 1α-calcidiol which improved their clinical phenotypes except for alopecia.

A novel frameshift deletion in PLS3 causing severe primary osteoporosis

Mutations in the gene encoding plastin-3, PLS3, have recently been associated to severe primary osteoporosis. The molecular function of plastin-3 is not fully understood. Since PLS3 is located on the X chromosome, males are usually more severely affected than females. PLS3 mutations have thus far been reported in approximately 20 young patients with low bone mineral density (BMD). We describe an 8-year-old Greek boy with severe primary osteoporosis with multiple vertebral compression fractures and one low-energy long bone fracture. His clinical manifestations were consistent with osteogenesis imperfecta, including blue sclerae, joint hypermobility, low bone mineral density, kyphosis, bilateral conductive hearing loss, and mild dysmorphic features. The family history was negative for primary osteoporosis. COL1A1 and COL1A2 mutations were excluded by Sanger sequencing. However, Sanger sequencing of PLS3 led to the identification of a de novo frameshift deletion, NM_005032: c.1096_1100delAACTT, p.(Asn366Serfs*5), in exon 10 confirming the diagnosis of PLS3 osteoporosis. In conclusion, we describe a novel frameshift deletion in PLS3 causing severe primary osteoporosis in a boy. Our finding highlights the clinical overlap between type I collagen and PLS3-related skeletal fragility and underscores the importance of PLS3 screening in patients with multiple fractures to enable proper genetic counseling.

A new COL1A1 mutation in a Greek patient with osteogenesis imperfecta: Response to a low-dose protocol of zoledronic acid and two-year follow-up

Michail Sarantis, Panagoula Kollia, Stavroula Samara, Helen Athanasopoulou, Yolanda Gyftodimou, Dimitra Lianou, Evdoxia Mpourazani, Artemis Doulgeraki 4 Department of Trauma and Orthopaedics, KAT Hospital, Athens, Greece; Department of Genetics & Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece; Department of Bone and Mineral Metabolism, Institute of Child Health, Athens, Greece; Department of Clinical Genetics, Institute of Child Health, Athens, Greece; 1 Department of Pediatrics, “Aghia Sophia” Children’s Hospital, Athens, Greece

Autosomal Recessive Osteogenesis Imperfecta Caused by a Novel Homozygous COL1A2 Mutation

Osteogenesis imperfecta (OI) is a skeletal dysplasia characterized by brittle bones and extraskeletal manifestations. The disease phenotype varies greatly. Most commonly, OI arises from monoallelic mutations in one of the two genes encoding type I collagen, COL1A1 and COL1A2 and is inherited as an autosomal dominant trait. Here, we describe a consanguineous family with autosomal recessive OI caused by a novel homozygous glycine substitution in COL1A2, NM_000089.3: c.604G>A, p.(Gly202Ser), detected by whole-genome sequencing. The index patient is a 31-year-old Greek woman with severe skeletal fragility. She had mild short stature, low bone mineral density of the lumbar spine and blue sclerae. She had sustained multiple long bone and vertebral fractures since childhood and had been treated with bisphosphonates for several years. She also had an affected sister with similar clinical manifestations. Interestingly, the parents and one sister, all carriers of the COL1A2 glycine mutation, did not have manifestations of OI. In summary, we report on autosomal recessive OI caused by a homozygous glycine-to-serine substitution in COL1A2, leading to severe skeletal fragility. The mutation carriers lacked OI manifestations. This family further expands the complex genetic spectrum of OI and underscores the importance of genetic evaluation for correct genetic counselling.

Basic laboratory bone profile in Greek patients with galactose metabolic disorders

Maria Kalogerakou, Kleopatra H. Schulpis, Artemis Doulgeraki, George I. Lambrou Department of Inborn Errors of Metabolism, Institute of Child Health, “Aghia Sofia” Children’s Hospital, Athens, Greece; Post Graduate Programme “Metabolic Bone Diseases”, National and Kapodistrian University of Athens, Medical School, Athens, Greece; Department of Bone and Mineral Metabolism, Institute of Child Health, “Aghia Sofia” Children’s Hospital, Athens, Greece; First Department of Pediatrics, University of Athens, Choremeio Research Laboratory, National and Kapodistrian University of Athens, Greece