Clinical and biochemical response to neridronate treatment in a patient with osteoporosis-pseudoglioma syndrome (OPPG).

Osteoporosis-pseudoglioma syndrome (OPPG) is a rare autosomal recessive syndrome characterized by juvenile-onset osteoporosis and ocular abnormalities due to a low-density lipoprotein receptor-related protein 5 (LRP5) gene mutation. Treatment with bisphosphonates, particularly with pamidronate and risedronate, has been reported to be of some efficacy in this condition. We report on a patient with OPPG due to an LRP5 gene mutation, who showed an encouraging response after a 36-month period of neridronate therapy. We report a case of a patient treated with bisphosphonates. Bisphosphonates should be administered in OPPG patients as a first-line therapy during early childhood.

Serum creatine kinase isoenzymes in children with osteogenesis imperfecta.

This study evaluates serum creatine kinase isoenzyme activity in children with osteogenesis imperfecta to determine its usefulness as a biochemical marker during treatment with bisphosphonate. The changes of creatine kinase (CK) isoenzyme activity during and after discontinuation therapy were observed. These results could be useful in addressing over-treatment risk prevention. INTRODUCTION: The brain isoenzyme of creatine kinase (CKbb) is highly expressed in mature osteoclasts during osteoclastogenesis, thus plays an important role in bone resorption. We previously identified high serum CKbb levels in 18 children with osteogenesis imperfect (OI) type 1 treated for 1 year with bisphosphonate (neridronate). In the present study, serum CK isoenzymes were evaluated in the same children with continuous versus discontinued neridronate treatment over a further 2-year follow-up period. METHODS: This study included 18 children with OI type 1, 12 with continued (group A) and 6 with ceased (group B) neridronate treatment. Auxological data, serum biochemical markers of bone metabolism, bone mineral density z-score, and serum total CK and isoenzyme activities were determined in both groups. RESULTS: Serum CKbb was progressively and significantly increased in group A (p < 0.004) but rapidly decreased to undetectable levels in group B. In both groups, the cardiac muscle creatine kinase isoenzyme (CKmb) showed a marked decrease, while serum C-terminal telopeptide (CTx) levels were almost unchanged. CONCLUSIONS: This study provides evidence of the cumulative effect of neridronate administration in increasing serum CKbb levels and the reversible effect after its discontinuation. This approach could be employed for verifying the usefulness of serum CKbb as a biochemical marker in patients receiving prolonged bisphosphonate treatment. Moreover, the decreased serum CKmb levels suggest a systemic effect of these drugs.

Reliability of vertebral fractures assessment (VFA) in children with osteogenesis imperfecta.

The aim of this study is to evaluate the diagnostic accuracy of vertebral fractures assessment (VFA) in comparison with conventional radiography in identifying vertebral fractures in children and adolescents affected by OI. On 58 patients (33 males, 25 females; age range 1-18 years; 41 children and 17 adolescents) with osteogenesis imperfecta (OI type I, n = 44, OI type III, n = 4; OI type IV, n = 10), lateral spine images by radiographs and by dual-energy X-ray absorptiometry (DXA) were acquired. For vertebral fracture diagnosis, plain radiographs were used as "gold standard" and VFA and morphometric X-ray absorptiometry (MXA) were performed. The visualized vertebrae were 738 (97.9%) by radiographs and 685 (90.9%) by DXA of a total of 754 vertebrae from T4 to L4. VFA and MXA identified, respectively, 129 (74%) and 116 (66%) of the 175 vertebral fractures detected by radiographs. Radiographs identified 36 patients with vertebral fractures, VFA 35 and MXA 41 (6 false positives). On a per vertebra basis, radiographs and VFA had elevated agreement (93.9%; k score 0.81, 95% CI 0.76-0.86), that resulted slightly lower for MXA (90.6%; k score 0.72, 95% CI 0.65-0.78). VFA and MXA demonstrated high sensitivity (95.6 and 94.1 %, respectively) while specificity was 100% for VFA and 90.6% for MXA on a per patient basis; the agreement was excellent for VFA (98.3%; k score 0.96, 95% CI 0.89-1.03) and good for MXA (87.9%; k score 0.73, 95% CI 0.55-0.91). The diagnostic performance parameters resulted better for VFA (sensitivity 95.6%; specificity 100%; PPV 100%; NPV 97.2%), than for MXA (sensitivity 94.1%; specificity 85.4%; PPV 72.7%; NPV 97.2%). The results of our study demonstrate the reliability of VFA for diagnosis of vertebral fractures in children with OI suggesting its use as a more safe and practical alternative to conventional radiography.

Novel mutations affecting LRP5 splicing in patients with osteoporosis-pseudoglioma syndrome (OPPG).

Osteoporosis-pseudoglioma sydrome (OPPG) is an autosomal recessive disorder with early-onset severe osteoporosis and blindness, caused by biallelic loss-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. Heterozygous carriers exhibit a milder bone phenotype. Only a few splice mutations in LRP5 have been published. We present clinical and genetic data for four patients with novel LRP5 mutations, three of which affect splicing. Patients were evaluated clinically and by radiography and bone densitometry. Genetic screening of LRP5 was performed on the basis of the clinical diagnosis of OPPG. Splice aberrances were confirmed by cDNA sequencing or exon trapping. The effect of one splice mutation on LRP5 protein function was studied. A novel splice-site mutation c.1584+4A>T abolished the donor splice site of exon 7 and activated a cryptic splice site, which led to an in-frame insertion of 21 amino acids (p.E528_V529ins21). Functional studies revealed severely impaired signal transduction presumably caused by defective intracellular transport of the mutated receptor. Exon trapping was used on two samples to confirm that splice-site mutations c.4112-2A>G and c.1015+1G>T caused splicing-out of exons 20 and 5, respectively. One patient carried a homozygous deletion of exon 4 causing the loss of exons 4 and 5, as demonstrated by cDNA analysis. Our results broaden the spectrum of mutations in LRP5 and provide the first functional data on splice aberrations.

Taurine deficiency in thalassemia major-induced osteoporosis treated with neridronate.

The aetiology of thalassemia major-induced osteoporosis is multifactorial. Up to now, bisphosphonates seem to be a promising therapy. Taurine is found in a high concentration in bone cells enhancing bone tissue formation and inhibiting bone loss. Recently we found a decrease taurine plasma level in children affected by osteogenesis imperfecta during neridronate (amino-bisphosphonate) therapy suggesting a possible interaction between pharmacological effect of this drug and taurine availability. On the basis of these results, we performed plasma and urine amino acid (AA) analysis in thalassemia major-induced osteoporosis before and after 12 months of neridronate treatment. Twelve patients, five males and seven females, aged from 20 to 29 years following a hypertransfusion treatment protocol were enrolled in the study. Patients were treated with neridronate infusion every one month (30 mg in 100ml of saline). Plasma and urine specimens for AA analysis, bone mineral density, bone mineral content and vertebral project area were examined at baseline (T0) and after 12 months of treatment (T12). A significant decrease was observed for plasma level and urinary excretion of taurine (T0 vs. T12=p<0.01) whereas bone mineral content and vertebral projection area showed a statistical significant increase (T0 vs. T12=p<0.05). These results and other experimental researches warrant further studies examining the long-term effect of taurine supplementation in association with neridronate treatment.

Absence of severe recurrent infections in glycogen storage disease type Ib with neutropenia and neutrophil dysfunction.

We describe a 10-year-old boy with glycogen storage disease type Ib (GSD Ib) with neutropenia and neutrophil dysfunction who never suffered from severe recurrent infections. Lymphocyte subpopulations and assay of intracellular cytokines (IL-2, IL-4 and IFN-gamma) showed a pattern of lymphocyte activation suggesting a shift of T(H)1/T(H)2 balance towards a T(H)1 response. This is the first report of GSD Ib without severe recurrent infections in spite of neutropenia and neutrophil dysfunction.

Fatty acid profile of oesophageal mucosa in children with gastro-oesophageal reflux disease.

BACKGROUND: Polyunsaturated fatty acids, as precursors of eicosanoids, are involved in the pathogenesis of oesophageal mucosal damage and healing. AIMS: To evaluate a possible role of polyunsaturated fatty acids in the pathogenesis of gastro-oesophageal reflux, we assayed fatty acids profile of oesophageal mucosal specimens obtained by endoscopy in children without oesophageal disease and children affected by gastro-oesophageal reflux disease. PATIENTS: Eighteen children with normal 24-h oesophageal pH monitoring (GOR- group) and 18 children with gastro-oesophageal reflux disease (GOR+ group, eight with oesophagitis and 10 without), were included in the study. METHODS: Fatty acids were extracted from oesophageal mucosal specimens obtained by endoscopy and assayed by gas chromatography. RESULTS: In the GOR+ group we observed an increased percentage of mucosal polyunsaturated fatty acids, mainly arachidonic and docosohexaenoic acids (p<0.01), without differences between groups with and without oesophagitis. Significant positive correlation was found between reflux index and docosahexaenoic acid (r=0.805; p<0.001). CONCLUSIONS: The results obtained show that the current methods are able to reveal changes between normal and pathological mucosa that could be relevant in the pathogenesis of gastro-oesophageal reflux disease.

Increased taurine content in esophageal mucosa of children affected by gastroesophageal reflux.

We studied the possible involvement of mucosal amino acid metabolism in the pathogenesis of gastroesophageal reflux disease in children. Eighteen children with gastroesophageal reflux disease (8 with reflux esophagitis and 10 without) and 10 children with normal 24-h esophageal pH monitoring as a comparative group underwent esophagogastroduodenoscopy with biopsies. Plasma and esophageal mucosa amino acids were assayed by liquid chromatography. In children affected by gastroesophageal reflux disease we found an increase of mucosal taurine (P < 0.01) and a decrease of serine (P < 0.01). No differences were noted between patients with and without esophagitis. Significant positive correlations (P < 0.001; r = 0.626) were found between mucosal taurine content and reflux index. Plasma amino acid concentrations did not show any significant differences among groups. Our results indicate that biochemical alterations precede the histological findings of inflammation, likely reflecting the adaptive response of the esophageal mucosa to the gastric contents exposure.

Sandifer's syndrome in a breast-fed infant.

Sandifer's syndrome is a rare manifestation of gastroesophageal reflux (GER) in children, occurring in association with abnormal movements of the head, neck, and upper part of the trunk. Out of 65 children with Sandifer's syndrome described in literature, only 2 were breast-fed. We report on a 15-day-old breast-fed girl affected by Sandifer's syndrome. Pathological GER was diagnosed with 24 h pH esophageal monitoring. In our patient, all the symptoms of Sandifer's syndrome disappeared when she was cow's milk formula-fed. The role of food allergy to dietary proteins ingested by a lactating mother is discussed.

Determination of urinary orotic acid and uracil by capillary zone electrophoresis.

We describe a simple method for measuring orotic acid and uracil concentration in urine by capillary zone electrophoresis in 20 mM Na-borate buffer, pH 9.2. The method was applied for studying a patient with HHH (hyperomithinemia, hyperammonemia and homocitrullinuria) syndrome. A high value of uracil excretion was found during periods of relatively low orotic acid excretion and normal ammonemia. The orotic acid level in urine was increased by increasing protein intake.

Effect of D-ribose on purine synthesis and neurological symptoms in a patient with adenylosuccinase deficiency.

Oral supplementation of 10 mmol/kg/day of D-ribose to a patient with an inherited deficit of adenylosuccinase, severe psychomotor retardation, and epilepsy caused a marked increase in plasma concentration and urinary excretion of urate, while minor changes in succinylpurine levels were observed. D-Ribose administration was accompanied by a slight improvement of behaviour and a progressive reduction of seizure frequency, which increased dramatically upon two attempts to withdraw the drug. Substitution of D-ribose with an equivalent amount of D-glucose did not result in an increase of seizure frequency.

Usefulness of cyanide-nitroprusside test in detecting incomplete recessive heterozygotes for cystinuria: a standardized dilution procedure.

We present the results of a cyanide-nitroprusside test (CNT) after a standardized dilution procedure of urine samples and report the efficiency of this method in detecting heterozygotes for cystinuria when applied on an open pediatric population. In the preliminary study we assayed by quantitative determination of amino acids 162 urine samples from a hospital population identifying 24 type III heterozygotes and 2 type II heterozygotes for cystinuria. The classic CNT gave 38 false positive results and 5 false negative results showing a sensitivity and specificity of 0.808 and 0.721, respectively. When progressively diluted, all samples of heterozygotes remained CNT positive up to a creatinine concentration of 90 mg/dl. At this level of dilution 31 out of 38 false positive turned to negative, thus obtaining a specificity of 0.922 without a lowering of the sensitivity in detecting heterozygotes. The standardized dilution at 90 mg/dl of creatinine concentration was applied to 74.7% of a population of 1024 schoolchildren. In this way 163 out of 210 positive results were eliminated and thus the specificity of CNT rose from 0.789 to 0.953. On the basis of these results, the method proposed can be regarded as reliable and useful for a screening program in detecting heterozygotes for cystinuria.

Erythrocyte and plasma levels of glutamate and aspartate in children affected by migraine.

In this study we determined plasma and erythrocyte amino acids in children affected by migraine, in order to evaluate glutamate and aspartate metabolism in the pathogenesis of this disorder. Fifteen children with migraine with aura (mean age +/- SD = 10.3 +/- 1.56), 19 children with migraine without aura (mean age +/- SD = 10.4 +/- 1.48) and 16 healthy normal controls (mean age +/- SD 10.6 +/- 1.53) were investigated. In both migraine groups there were significantly lower plasma glutamate and aspartate levels and significantly higher erythrocyte/plasma concentration (E/P) ratios of these amino acids with respect to the controls. Erythrocyte aspartate concentrations were significantly elevated in migraine children compared to the controls, while erythrocyte glutamate concentrations showed no significant differences between groups. Similar results were observed in both migraine groups. These results seem to suggest the presence of a higher activity of the erythrocytes' glutamate/aspartate transport system that could reflect a similar alteration at the neuronal/glial cell level in the CNS. Our study suggests an imbalance of the excitatory amino acid turnover in the pathogenesis of migraine in children.

Irritable oesophagus syndrome as cause of chronic cough.

Case of an infant with chronic cough is reported. The most frequent causes of chronic cough were ruled out. Twenty-four hour oesophageal pH-monitoring showed a close correlation between gastro-oesophageal reflux episodes and cough attacks. The patient was successfully treated with cisapride (0.3 mg/kg t.i.d.). These findings show that irritable oesophagus syndrome can cause chronic cough.

Abnormal intestinal permeability in children with autism.

We determined the occurrence of gut mucosal damage using the intestinal permeability test in 21 autistic children who had no clinical and laboratory findings consistent with known intestinal disorders. An altered intestinal permeability was found in 9 of the 21 (43%) autistic patients, but in none of the 40 controls. Compared to the controls, these nine patients showed a similar mean mannitol recovery, but a significantly higher mean lactulose recovery (1.64% +/- 1.43 vs 0.38% +/- 0.14; P < 0.001). We speculate that an altered intestinal permeability could represent a possible mechanism for the increased passage through the gut mucosa of peptides derived from foods with subsequent behavioural abnormalities.