Patrizia D'Eufemia

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.

Low serum tryptophan to large neutral amino acids ratio in idiopathic infantile autism.

The serum tryptophan to large neutral amino acids ratio (Try/LNAA) is considered a reliable marker of tryptophan availability for brain serotonin synthesis. A dysfunction of brain serotonergic activity has been postulated to exist in autistic disorder and supported by recent studies. On this basis, we determined the serum amino acids levels in 40 children with idiopathic infantile autism as well as in 46 control children. A significantly lower serum Try/LNAA ratio was observed in the autistic subjects compared to the normal controls. In 14 autistic children (35%) this ratio was 2 SD below the mean value obtained in the control group. These results suggest that a low brain tryptophan availability due to a low serum Try/LNAA ratio could be one of the possible mechanisms involved in the alteration of serotonergic function in autism.

Chronic Tyrosinemia Associated with 4-Hydroxyphenylpyruvate Dioxygenase Deficiency with Acute Intermittent Ataxia and without Visceral and Bone Involvement

A 17-month-old girl, with acute intermittent ataxia and drowsiness, had hypertyrosinemia (serum tyrosine, 62 μmole/dl) and phenolic aciduria in the absence of hepatic, renal, eye or skin lesions. Serum methionine and urinary >-aminotevulinic acid concentrations were normal. Her psychomotor development was also normal. Protein restriction and vitamin C therapy failed to correct the biochemical abnormality. Liver biopsy was histologically normal.Analysis of the enzymes in the fiver biopsy, taken at 25 months of age, showed no detectable activity of 4-hydroxypbenylpyruvate dioxygenase (4HPPD), either in whole homogenate or cytosol fraction. Mixing experiments revealed no inhibitor of either 4HPPD or tyrosine aminotransferase (TAT).TAT in unfractionated liver was 0.23 μmole/mg protein/h (control, 0.10–0.30 μmole/mg protein/h; n = 5). In mitochondria, TAT was 0.24 μmole/mg protein/h (control, 0.09–0.12 μmole/mg protein/h; n = 3) whereas in cytosol fraction it was 0.23 μmole/mg protein/h (control, 0.27–0.44 μmole/mg protein/h; n = 3). Glutamate dehydrogenase activity appeared in the cytosol fraction suggesting some rupture of mitochondria during fractionation of the patients liver and indicating that true cytosol TAT might be somewhat lower than indicated; however, the kinetics of the patients cytosol TAT were normal: Km for tyrosine, 4.5 X 10-3 M (control, 4.0 x 10-3 M); Km for α-ketoglutarate, 98 x 10-6 M (control, 75 X 10-6 M); approxhnate Km for pyridoxal phosphate, 2.1 X 10-6 M (control, 4.0 X 10-6 M). Vmax in patient liver was 0.37 μmole/mg protein/h (control, 0.88 μmole/mg protein/h). These data argue against a primary abnormality of TAT but are consistent with a defect of 4HPPD; thus, this patient appears to represent a previously undescribed form of tyrosinemia.

Impairment of diastolic function in adult patients affected by osteogenesis imperfecta clinically asymptomatic for cardiac disease: Casuality or causality?

Osteogenesis imperfecta (OI) is a rare inherited connective disorder causing increased bone fragility and low bone mass. OI includes severe bone fragility, impaired dentinogenesis, with less common alterations in the joints, blood vessels, heart valves, skin. Interestingly, description of left ventricular rupture, aortic dissection and heart valves incompetence has been previously described. Death may occur in OI patients for cardiac disease in asyntomatic subjects. Aim of our study has been to evaluate the presence of potential subclinical cardiac disorders and to characterize cardiac functional parameters by echocardiography in adults with OI in absence of cardiac symptoms. Forty patients (21 females and 19 males) affected by type I, III, IV OI and 40 control subjects (20 females and 20 males) were evaluated in the study. Patients and controls underwent clinical examination, screening for endocrine and metabolic disorders, 12-lead electrocardiogram and echocardiogram. In particular, all subjects were evaluated by two-dimensional echocardiography with continuous- and pulse-wave Doppler. Patients and controls belonged to NYHA class I and no significant electrocardiographic alteration was documented in both groups. Thirty-eight patients (95%) showed valvular regurgitation compared to one control subject (2.5%; P<0.001). As regards the diastolic function parameters, in OI patients E wave velocity was reduced by 23% (95% CI: 9% to 29%; P<0.001), E/A ratio was reduced by 17% (95% CI: 15% to 26%; P<0.001) while isovolumetric relaxation time (IRT) was increased by 47% (95% CI: 26% to 53%; P<0.001) and E wave deceleration time (DT) was increased by 18% (95% CI: 13% to 26%; P<0.001) compared to controls. In conclusion, our data indicate that adult patients affected by OI have an altered diastolic function in absence of other metabolic alterations. These diastolic echocardiographic parameters might worsen over time, especially if other cardiovascular risk factors (e.g., smoking, hypertension, metabolic and endocrine alterations) are not carefully checked, monitored and treated. In the context of a multidisciplinary evaluation of OI patients, our data suggest that a careful cardiological evaluation of these patients is indicated beside skeletal evaluation and therapeutical skeletal options.

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

Abstract 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.

A three month-old infant with severe hyperchylomicronemia: Molecular diagnosis and extracorporeal treatment

OBJECTIVE Chylomicronemia syndrome presenting in childhood is a rare recessive disorder due to mutations of lipoprotein lipase (LPL) and more rarely of APOC2, APOA5, GPIHBP1 or LMF1 genes. It often requires urgent and suitable treatment to avoid acute pancreatitis. The aim of this study was the molecular characterization and treatment of a 3 month-old infant with plasma triglycerides (TG) > 300 mmol/L. METHODS All candidate genes were sequenced. The patient was submitted to one plasma-exchange (PEX) procedure and subsequently to a rigid lipid-lowering diet (milk: Monogen(®)). RESULTS The proband was homozygous for a novel LPL mutation (c.242G > A, p.G81D) which in silico results pathogenic. After PEX, which was well tolerated, TG dropped to 64 mmol/L. During 5-month follow-up there was a clear trend towards lower and stable TG values. CONCLUSION PEX is applicable in subjects with very low body weight when the extreme severity of the clinical picture has no therapeutic alternatives.

Amoxycillin and clavulanic acid in the treatment of urinary tract infections in children

The efficacy of amoxicillin–clavulanic acid combination in the treatment of urinary tract infections resistant, in vitro, to amoxycillin was studied in 42 children. Of the 24 children with urinary tract infection for the first time, combination therapy, dosing twice daily for 5 days (40 mg/kg·day), cleared the infection in 23 (96%) cases. Relapse occurred in four (17%) cases within 30 days. Of the 18 children who presented with recurrent urinary tract infections therapy, as above, cleared the infection in 16 (89%) cases. In these cases, long-term therapy was performed at a dosage of 20 mg/kg once daily. Tolerance was good; gastro-intestinal disorders in five (12%) cases which regressed by dosing at 8 h rather than 12 h intervals. In conclusion, amoxycillin–clavulanic acid can be considered a first choice treatment of urinary tract infections in children.

Osteogenesis imperfecta: the audiological phenotype lacks correlation with the genotype

BackgroundOsteogenesis Imperfecta (OI) is a heritable connective tissue disorder mainly caused by mutations in the genes COL1A1 and COL1A2 and is associated with hearing loss in approximately half of the cases. The hearing impairment usually starts between the second and fourth decade of life as a conductive hearing loss, frequently evolving to mixed hearing loss thereafter. A minority of patients develop pure sensorineural hearing loss. The interindividual variability in the audiological characteristics of the hearing loss is unexplained.MethodsWith the purpose of evaluating inter- and intrafamilial variability, hearing was thorougly examined in 184 OI patients (type I: 154; type III: 4; type IV: 26), aged 3-89 years, with a mutation in either COL1A1 or COL1A2 and originating from 89 different families. Due to the adult onset of hearing loss in OI, correlations between the presence and/or characteristics of the hearing loss and the underlying mutation were investigated in a subsample of 114 OI patients from 64 different families who were older than 40 years of age or had developed hearing loss before the age of 40.ResultsHearing loss was diagnosed in 48.4% of the total sample of OI ears with increasing prevalence in the older age groups. The predominant type was a mixed hearing loss (27.5%). A minority presented a pure conductive (8.4%) or pure sensorineural (12.5%) loss. In the subsample of 114 OI subjects, no association was found between the nature of the mutation in COL1A1 or COL1A2 genes and the occurrence, type or severity of hearing loss. Relatives originating from the same family differed in audiological features, which may partially be attributed to their dissimilar age.ConclusionsOur study confirms that hearing loss in OI shows a strong intrafamilial variability. Additional modifications in other genes are assumed to be responsible for the expression of hearing loss in OI.

Audiologic phenotype of osteogenesis imperfecta: use in clinical differentiation.

Objectives To describe the audiologic phenotype in osteogenesis imperfecta (OI). Study Design Observational study. Setting Tertiary referral center. Patients One hundred eighty-two patients with genetically confirmed OI, aged 3 to 89 years. Intervention Diagnostic hearing evaluation through otoadmittance and acoustic stapedius reflex measurements, pure tone, and speech audiometry. Main Outcome Measure(s) Prevalence, type, severity, symmetry, and audiometric configuration of the hearing loss in OI. Progression of hearing thresholds was determined by constructing age-related typical audiograms. Results Approximately 52.2% of all OI patients demonstrated hearing loss unilaterally (7.7%) or bilaterally (44.5%). Pure conductive, mixed, and pure sensorineural hearing losses were observed in 8.5%, 37.8%, and 11.6% of OI ears, respectively. Multiple linear regression revealed that thresholds progressed by 0.5 dB/yr at 0.25 kHz to 0.8 dB/yr at 0.8 kHz in the ears with conductive or mixed hearing loss. Pure sensorineural hearing loss progressed by less than 0.1 dB/yr at 0.25 kHz to 1.2 dB/yr at 8.0 kHz. Audiometric configuration was predominantly flat (70.5%) in the ears with conductive/mixed loss and sloping (50.0%) in those with pure sensorineural loss. Conclusion Patients with OI are at risk for hearing loss. The hearing loss in OI may initiate at a young age and is progressive. However, the rate of progression, as well as the hearing loss severity, onset, and configuration depend on the type of hearing loss, which may be conductive/mixed or pure sensorineural. For both types, age-related threshold audiograms are constructed and may help the clinician to estimate the course of the hearing loss in patients with OI. In addition, they may be valuable to distinguish between hearing loss associated with OI and other similar forms of hearing loss, such as in otosclerosis.

Neutrophil Glutamine Deficiency in Relation to Genotype in Children with Cystic Fibrosis

Pulmonary disease in cystic fibrosis (CF) is characterized by a chronic neutrophil-dominated inflammation of lung tissue. Inasmuch as some amino acids (AA) play a pivotal role in various aspects of neutrophil metabolism, the aim of this study was to investigate a possible alteration of neutrophil AA metabolism and to evaluate its relation (if any) with the genotype. We performed plasma and neutrophil AA analysis in 26 CF patients with known genotype, 10 patients with non-CF bronchiectasis, and 20 normal subjects. The CF group showed a significant decrease of free intracellular neutrophil glutamine (Gln) content compared with controls and the non-CF bronchiectasis group. In the latter group, levels of neutrophil Gln were significantly lower compared with the controls. Amino acid plasma concentration in non-CF bronchiectasis showed a decrease of Gln and taurine compared with controls. Neutrophil Gln content showed values significantly lower in CF patients with severe mutations (class I, II, and III mutations) compared with mild mutations (class IV and V mutations). Results of our study add further evidence for intrinsic neutrophil alterations that could play an important role in the pathogenesis of chronic pulmonary disease in CF patients.