Hyperornithinaemia-hyperammonaemia-homocitrullinuria syndrome is caused by mutations in a gene encoding a mitochondrial ornithine transporter.

Neurospora crassa ARG13 and Saccharomyces cerevisiae ARG11 encode mitochondrial carrier family (MCF) proteins that transport ornithine across the mitochondrial inner membrane. We used their sequences to identify EST candidates that partially encode orthologous mammalian transporters. We thereby identified such a gene (ORNT1) that maps to 13q14 and whose expression, similar to that of other urea cycle (UC) components, was high in liver and varied with changes in dietary protein. ORNT1 expression restores ornithine metabolism in fibroblasts from patients with hyperammonaemia-hyperornithinaemia-homocitrullinuria (HHH) syndrome. In a survey of 11 HHH probands, we identified 3 ORNT1 mutant alleles that account for 21 of 22 possible mutant ORNT1 genes in our patients: F188delta, which is common in French-Canadian HHH patients and encodes an unstable protein; E180K, which encodes a stable, properly targeted protein that is inactive; and a 13q14 microdeletion. Our results show that ORNT1 encodes the mitochondrial ornithine transporter involved in UC function and is defective in HHH syndrome.

Opposing influences of dexamethasone and retinoic acid on adenylate cyclase activity in ROS 17/2.8 cells.

Exposure of ROS 17/2.8 cells to dexamethasone (DEX) or retinoic acid (RA) increases and decreases, respectively, adenylate cyclase activity (ACA) in response to isoproterenol, forskolin, guanylylimidodiphosphate, or NaFl. Despite dramatic changes in ACA, there were no significant changes in levels of cholera toxin- or pertussis toxin (PT)-dependent ADP-ribosylation of membranes prepared from cells after DEX or RA exposure as compared to controls. Similarly, immunochemical detection of alpha S, alpha i1-3, and alpha O, as well as Northern blot analysis of messenger RNA for each of the respective GTP binding proteins, also failed to demonstrate an influence of DEX or RA when contrasted with controls. In a novel use of the cyc- reconstitution assay, wherein the influence of inhibitory guanine nucleotide binding proteins in the extracts of control, DEX-, and RA-treated membranes is removed by a previous 24-h incubation with PT in the intact cell, we demonstrate that this PT treatment markedly enhances ACA in the cyc- reconstitution assay for all three preparations, but that the fold-increase due to PT-treatment is greatest in RA-treated cells. The greater magnitude of the effect of PT on RA-treated ROS 17/2.8 cells, in the absence of any obvious quantitative changes in the levels of the PT substrates, suggests that the effect of RA on ROS 17/2.8 cells appears to be an augmentation of the influence of inhibitory guanine nucleotide binding proteins, ultimately leading to reduced ACA.

Facilitated diagnosis of the contiguous gene syndrome: tuberous sclerosis and polycystic kidneys by means of haplotype studies.

Tuberous sclerosis (TSC) and autosomal dominant polycystic kidney disease (ADPKD) are genetically heterogeneous diseases. The major gene for ADPKD (PKD1) lies adjacent to the TSC2 gene on chromosome 16p13. Some reports in the literature referred to an unusual presentation of TSC with enlarged cystic kidneys at birth, but it was not until the localization of the TSC2 and PKD1 genes that it was possible to analyze the interaction between both genes. We describe a case of a child with TSC and enlarged cystic kidneys. The study of genetic marker segregation in the family pointed to the presence of a deletion involving the 3' region of PKD1. A further study of the region showed a deletion of 40 kb involving both PKD1 and TSC2. We suggest that an additive or synergistic effect between PKD1 and TSC2 may cause this renal phenotype. A contiguous gene syndrome involving PKD1 and TSC2 should be suspected in children with TSC and enlarged polycystic kidneys at birth. The first approach to identify a deletion of both genes could be the analysis of the segregation of PKD1 and TSC2 markers in the family.

Growth of the pulmonary arteries following Blalock-Taussig shunt.

The Blalock-Taussig (BT) shunt remains the standard systemic-to-pulmonary artery shunt. We reviewed our experience with the classic BT shunt in terms of mortality, patency, duration of palliation, and growth of the pulmonary artery. Records were reviewed in 49 consecutive patients, 25 of whom were less than one month old at the time of operation. They underwent a total of 53 BT shunts. Also, the pulmonary artery index (PAI), or the sum of the cross-sectional areas of the right and left pulmonary arteries standardized by the body surface area (BSA), was calculated. There were 4 operative deaths (7.5%) and 1 late death (2.0%). Early shunt thrombosis (within 72 hours postoperatively) occurred in 3 patients. Four patients required a second BT shunt, 5 underwent a palliative outflow tract reconstruction, and 5 required a polytetrafluoroethylene graft. Twenty-one patients underwent a corrective procedure, and 26 underwent a second cardiac catheterization. Of these 26 patients, 24 represent the subgroup used to assess the growth of the pulmonary arteries. The mean duration of palliation was 25.15 months. Mean PAI increased significantly from 127 +/- 40 mm2/BSA pre-shunt to 286.1 +/- 144 mm2/BSA post-shunt (p less than .004). This series demonstrates that the pulmonary arteries do grow after BT shunt. Pulmonary artery growth in patients with tetralogy of Fallot was greater than that in patients with single ventricle, and the duration of palliation was acceptable in most patients. Calculation of PAI may aid in the decision whether to perform a corrective surgical procedure or a second palliative shunt procedure.

[Neurologic presentation in haemolytic-uraemic syndrome]. / Manifestaciones neurológicas en el síndrome hemolítico urémico.

INTRODUCTION: Haemolytic-uraemic syndrome (HUS) is characterized by microangiopathic hemolytic anaemia, thrombopenia and multiorganic aggression, specially renal, gastrointestinal and central nervous system disturbances. Sporadic in Spain (2/1,500,000 inhabitants), its clinical onset includes acute renal failure, hypertension and central nervous system symptoms (irritability, drowsiness, convulsions, cortical blindness, hemiparesia or coma), due to metabolic distress, hypertension or central nervous system microangiopathy. Few long-term outcome studies have been published. PATIENTS AND METHODS: A retrospective analysis of a series of 58 patients with HUS between 1981 and 2006, is reported. Clinical onset, laboratory, electrophysiology, neuroimaging tests, and prognosis factors are reviewed, together with long-term clinical outcome. RESULTS: 22 children presented neurologic symptoms, seven had some neurological test; one patient died; in five some neurological sequelae persisted (hemiparesia, cognitive deficit, visual-perception deficit), the other 16 remaining asymptomatic. CONCLUSIONS: Neurological morbility is high in HUS (27% of the children with neurological symptoms), with a 1.7% mortality. Seizure at onset was not a poor prognosis factor in our group. No positive correlation can be established between neuroimaging and long-term outcome.

Accelerated ribosome formation and growth in neonatal pig hearts.

Rapid growth (5 mg dry heart/h) of the left ventricular free wall (LVFW) in the newborn pig heart accompanied by lack of growth of the right ventricular free wall (RVFW) represents a unique natural model of cardiac enlargement that is free of pathophysiological influences. By 3 days of life, LVFW was 71% larger than at 4 h of age. Rates of protein synthesis were measured during perfusion of isolated pig hearts with bicarbonate buffer containing glucose, lactate, insulin, and plasma concentrations of amino acids of an aortic pressure of 60 mmHg. In hearts from pigs that were 18 h of age, rates of protein synthesis were the same in RVFW and LVFW, but in 2-day-old pigs the rate was 52% greater in LVFW than RVFW. During the first 3 days of life, RNA content (mg/g) increased 3.4-fold faster in LVFW than RVFW. When RNA content was expressed per total heart portion, the increase was 7.9-fold greater. Because approximately 85% of total RNA is rRNA, these values indicated much more rapid formation of ribosomes in the LVFW than RVFW. When ribosome formation was measured in vitro in hearts from 48-h-old pigs, rates of formation were 39% greater in LVFW than RVFW, and at 18 h of age, ribosome formation was 40% faster in LVFW than RVFW. These findings indicated that formation of new ribosome preceded accelerated synthesis of total heart proteins. These findings indicated that rapid growth of LVFW compared with no growth of RVFW was associated with a 67% faster rate of ribosome formation and a 32% greater rate of protein synthesis.

[Diagnostic of the heart tumors in newborn and children (author's transl)]. / Diagnóstico de los tumores cardíacos en el recién nacido y lactante

Heart tumors in children are rare. Though of benign pathology they are clinically malignant and should be diagnosed early and promptly treated by surgery in spite of the poor results usually obtained. Any heart enlargement in the absence of congenital heart disease accompanied by rhythm and conduction troubles must be considered as suspect. Five cases of heart tumor are reported and clinically described. Four occurred in newborns and the remaining one before the age of one. Heart enlargement was a constant finding. The ECG findings were: W.P.W. syndrome, intraventricular conduction troubles and ventricular tachycardia, wandering pacemaker (one case each) and ventricular hypertrophy with surprisingly low voltages in the corresponding chest leads (two cases).

[Kawasaki's disease. a case presentation]. / Síndrome ganglionar mucocutáneo (enfermedad de Kawasaki) A propósito de un caso.

A case of Kawasaki's disease in a girl of 2 10/12 years of age is presented. She had a typical clinical picture, without cardiovascular afectation, and with good final results. Apparently this is the third case reported in the Spanish medical literature. Attention is called to the low incidence of MLNS in the western countries--only 50 cases reported--as compared with the great number reported from Japan. The problems of diagnosis and pathogeny are discussed, particularly their intimate relation to infantile polyarteritis nodosa, because of the similarities in the cardiovascular alterations in both processes, above all in mortal cases.

New approach to osteopenia in phenylketonuric patients.

AIM: To study bone mineralization in a group of phenylketonuric patients and to search for a possible relationship between bone mineral density, dietary control, serum minerals and nutrition intake. The response to treatment with low-dose 1.25-(OH)2 vitamin D in patients with osteopenia was evaluated. METHODS: Twenty-eight phenylketonuric patients (age range: 10-33 y) on dietary treatment were investigated. Bone density at the lumbar spine (Dual Energy X-ray Absorptiometry), bone formation markers (osteocalcin and bone alkaline phosphatase), serum minerals, index of dietary control and protein, vitamin D and mineral intakes were determined. RESULTS: Of the patients studied, 78.6% had good dietary compliance (462 +/- 89 micromol/L). Mean protein, vitamin D and mineral intakes met the recommended dietary allowances (RDAs). Nevertheless, 8 patients had calcium intakes lower than 1000 g/d, and a positive correlation between Z-score and calcium (r = 0.585; p = 0.002) or phosphorus intake (r = 0.546; p = 0.005) was observed. Osteopenia was detected in 14 patients (50%). Moreover, bone alkaline phosphatase in phenylketonuric patients older than 18 y of age was significantly lower than that in controls (p < 0.0001). No correlation was found between bone mineral density, age, serum minerals, bone formation markers or index of dietary control. Treatment with 0.25 microg/d calcitriol significantly increased bone density in 6 patients. CONCLUSION: A defect in bone mineralization was detected in 50% of patients in our series. The correct amount of formula intake seems to be necessary for bone mineralization in phenylketonuric patients. Calcitriol can be a useful treatment for these patients, although more studies are needed to confirm these results. Hypercalcaemia and hypercalciuria need to be carefully monitored.