Summary:We report studies of a Greek boy of gypsy origin that show that he has severe de¢ciency of glycine N-methyltransferase (GNMT) activity due to apparent homozygosity for a novel mutation in the gene encoding this enzyme that changes asparagine-140 to serine. At age 2 years he was found to have mildly elevated serum liver transaminases that have persisted to his present age of 5 years. At age 4 years, hypermethioninaemia was discovered. Plasma methionine concentrations have ranged from 508 to 1049 mmol/L. Several known causes of hypermethioninaemia were ruled out by studies of plasma metabolites: tyrosinaemia type I by a normal plasma tyrosine and urine succinylacetone; cystathionine b-synthase de¢ciency by total homocysteine of 9.4^12.1 mmol/L; methionine adenosyltransferase I/III de¢ciency by S-adenosylmethionine (AdoMet) levels elevated to 1643^2222 nmol/L; and S-adenosylhomocysteine (AdoHcy) hydrolase de¢ciency by normal AdoHcy levels. A normal plasma N-methylglycine concentration in spite of elevated AdoMet strongly suggested GNMT de¢ciency. Molecular genetic studies identi¢ed a missense mutation in the coding region of the boy's GNMT gene, which, upon expression, retained only barely detectable catalytic activity. The mild hepatitis-like manifestations in this boy are similar to those in the only two previously reported children with GNMT de¢ciency, strengthening the likelihood of a causative association. Although his de¢ciency of GNMT activity may well be more extreme, his metabolic abnormalities are not strikingly greater. Also discussed is the metabolic role of GNMT; several additional metabolite abnormalities found in these patients; and remaining questions about human GNMT de¢ciency, such as the long-term prognosis, whether other individuals with this defect are currently going undetected, and means to search for such persons.

Clinical complications resulting from unevenly iron accumulation in individual organs of patients with beta-thalassemia major can affect both expectancy and quality of life. Magnetic resonance imaging (MRI) offers a quantitative, noninvasive, accurate method for estimating iron levels in various tissues, not easily accessible with other techniques. The aim of this study was to evaluate and correlate the level of iron accumulation in different organs (anterior pituitary, myocardium, and liver) assessed with MRI, in children and young adults with beta-thalassemia major. Thirty children and young adults (13 female and 17 male patients) with homozygous beta-thalassemia, treated conventionally, were studied with hepatic, myocardial, and hypophyseal MRI. For liver and myocardium, we calculated the natural logarithm of the signal-to-air ratio in flash 2-dimensional sequences with electrocardiogram gating, whereas for anterior pituitary, the signal intensity was measured in sagittal T2 sequences. All scans were performed within 3 months. In 13 patients, data regarding liver iron concentrations (LIC) assessed by percutaneous liver biopsy were available. The mean of serum ferritin concentrations for 1 year before scans was calculated for each patient. MRI values in myocardium and liver showed a significant negative correlation to age (r=-0.73 and -0.69, respectively). For pituitary MRI, a linear regression with age was recorded in patients over 14 years of age (r=-0.67), whereas a relatively increased signal intensity reduction was recorded in pubertal subjects. Mean serum ferritin concentrations ranged from 252 to 5872 mug/L with an average of 1525+/-1047 mug/L. No statistical significant correlation was noted between mean ferritin levels versus liver, pituitary, and cardiac MRI values (r=-0.49, -0.28, and -0.1, respectively). Mean LIC values assessed by percutaneous biopsy were 13.76+/-11.6 mg/g of dry tissue. A statistically significant negative correlation was observed between liver MRI readings and LIC determined by biopsy (r=-0.89). None of the 3 organs studied with MRI were significantly correlated to each other. Pituitary to liver MRI values and liver to myocardial MRI values were moderately correlated (r=0.34 and 0.42, respectively). Pituitary MRI was not correlated at all to myocardial MRI (r=-0.001). In conclusion, iron accumulation in thalassemic patients is a procedure progressing with age, which seems to act independently in different organs. MRI represents a reliable, noninvasive method for assessing iron overload in various tissues, non-easily accessible with other techniques. Regular scanning, to recognize preclinically excessive iron deposits and intensified chelation therapy, can prevent serious and fatal complications.

This study was conducted in order to assess myocardial and liver iron concentrations (LICs) using serial magnetic resonance imaging (MRI) scans in patients with beta-thalassaemia major, over a 4-yr period, and consequently to compare the effectiveness of different chelation regimens. Fifty children and young adults with beta-thalassaemia major (27 boys and 23 girls) were recruited (mean age: 14.74 +/- 3.67 yr). All patients underwent detailed clinical examination, electrocardiography, echocardiography, myocardial and liver MRI at the beginning of the study, 2 and 4 yr after. Additionally, serum ferritin levels were regularly measured and data regarding LICs assessed by percutaneous liver biopsy were available in 26 patients. Both myocardial and liver MRI values showed a moderate inverse correlation with age (r = -0.379, P < 0.001 and r = -0.376, P < 0.001, respectively). Liver MRI was better correlated with serum ferritin concentrations (r = -0.342, P < 0.001) than myocardial MRI (r = -0.186, P = 0.011). Liver MRI values were highly correlated with LICs derived from percutaneous liver biopsy (r = -0.863, P < 0.001), whereas myocardial MRI values did not correlate at all with measurements derived from echocardiography. Regarding iron chelation treatment, patients receiving combined therapy with deferiprone and deferoxamine (DFO) significantly reduced myocardial iron overload during the 4-yr study period, whilst patients in monotherapy with DFO showed a significant increase in LIC.

We prospectively evaluated the incidence of gallbladder pseudolithiasis in children treated with high doses of ceftriaxone for a variety of serious infections. We also monitored the time interval needed for this phenomenon to develop and resolve completely after initiation and cessation of treatment, respectively. Included in this study are 44 children treated with ceftriaxone 100 mg/kg/d divided into 2 equal intravenous doses and followed by serial abdominal sonography. Eleven children developed pseudolithiasis of gallbladder 2-9 d after initiation of ceftriaxone therapy. Six children (54.5%) developed this complication within the first 3 d. Lithiasis completely resolved 8-23 d after the end of treatment. In conclusion, pseudolithiasis of the gallbladder developed in 25% of sick children and completely resolved in all patients. Early development of this complication was not exceptional. It occurred in more than half of these children.

We prospectively evaluated the incidence of gallbladder pseudolithiasis in children treated with high doses of ceftriaxone for a variety of serious infections. We also monitored the time interval needed for this phenomenon to develop and resolve completely after initiation and cessation of treatment, respectively. Included in this study are 44 children treated with ceftriaxone 100 mg/kg/d divided into 2 equal intravenous doses and followed by serial abdominal sonography. Eleven children developed pseudolithiasis of gallbladder 2‐9 d after initiation of ceftriaxone therapy. Six children (54.5%) developed this complication within the first 3 d. Lithiasis completely resolved 8–23 d after the end of treatment. In conclusion, pseudolithiasis of the gallbladder developed in 25% of sick children and completely resolved in all patients. Early development of this complication was not exceptional. It occurred in more than half of these children.