SENS-U: continuous home monitoring of natural nocturnal bladder filling in children with nocturnal enuresis - a feasibility study.

INTRODUCTION: Enuresis is a common problem in children. One treatment option is a wetting alarm that provides an alarm when incontinence occurs. A drawback of this approach is that the child is still awakened by wet sheets. Recently, a wearable, wireless ultrasonic bladder sensor became available, the SENS-U, which has the potential to prevent the enuretic event by waking up the child before the bladder is full. In this first feasibility study, the aim is to perform a night-time, home-based evaluation of the SENS-U in children with monosymptomatic nocturnal enuresis (MNE). PATIENTS AND METHODS: In this study, children (6-12 years) with MNE were included for a one-night monitoring session. During the night, the SENS-U continuously (i.e. every 30 s) estimated the filling status [notifications were deactivated]. In addition, urine volume was collected in a measurement cup (or diaper weight). The total measured natural nocturnal bladder filling (NNBF) cycles was analyzed by descriptive statistics. Before and after the measurement, sleep behavior was assessed by a selection of the Children's Sleep Habits Questionnaire. RESULTS: Fifteen patients (boys/girls: 13/2) [mean age: 8.6 ± 1.5 years] have been enrolled. One patient was excluded due to inadequate sensor-to-skin contact. For 14 children, 18 NNBF cycles were recorded (voiding diary) of which three patients (21%) had more than one NNBF cycle. The SENS-U was able to successfully detect 83% of the NNBF cycles. The three missed NNBF cycles had a voided volume ≤30 ml, which was at the lower limit of the sensor's detection range. The SENS-U had no effect on sleeping behavior. CONCLUSION: The SENS-U was able to monitor the natural nocturnal bladder filling successfully in children with monosymptomatic nocturnal enuresis at home, without disturbing their sleep. Future research focuses on investigating the usability of the SENS-U for both diagnostic - and treatment purposes.

Bone mineral density in children and adolescents with Prader-Willi syndrome: a longitudinal study during puberty and 9 years of growth hormone treatment.

CONTEXT: Longitudinal data on bone mineral density (BMD) in children and adolescents with Prader-Willi Syndrome (PWS) during long-term GH treatment are not available. OBJECTIVE: This study aimed to determine effects of long-term GH treatment and puberty on BMD of total body (BMDTB), lumbar spine (BMDLS), and bone mineral apparent density of the lumbar spine (BMADLS) in children with PWS. DESIGN AND SETTING: This was a prospective longitudinal study of a Dutch PWS cohort. PARTICIPANTS: Seventy-seven children with PWS who remained prepubertal during GH treatment for 4 years and 64 children with PWS who received GH treatment for 9 years participated in the study. INTERVENTION: The children received GH treatment, 1 mg/m(2)/day (≅ 0.035 mg/kg/d). MAIN OUTCOME MEASURES: BMDTB, BMDLS, and BMADLS was measured by using the same dual-energy x-ray absorptiometry machine for all annual measurements. RESULTS: In the prepubertal group, BMDTB standard deviation score (SDS) and BMDLSSDS significantly increased during 4 years of GH treatment whereas BMADLSSDS remained stable. During adolescence, BMDTBSDS and BMADLSSDS decreased significantly, in girls from the age of 11 years and in boys from the ages of 14 and 16 years, respectively, but all BMD parameters remained within the normal range. Higher Tanner stages tended to be associated with lower BMDTBSDS (P = .083) and a significantly lower BMADLSSDS (P = .016). After 9 years of GH treatment, lean body mass SDS was the most powerful predictor of BMDTBSDS and BMDLSSDS in adolescents with PWS. CONCLUSIONS: This long-term GH study demonstrates that BMDTB, BMDLS, and BMADLS remain stable in prepubertal children with PWS but decreases during adolescence, parallel to incomplete pubertal development. Based on our findings, clinicians should start sex hormone therapy from the age of 11 years in girls and 14 years in boys unless there is a normal progression of puberty.

Eight years of growth hormone treatment in children with Prader-Willi syndrome: maintaining the positive effects.

BACKGROUND: The most important reason for treating children with Prader-Willi syndrome (PWS) with GH is to optimize their body composition. OBJECTIVES: The aim of this ongoing study was to determine whether long-term GH treatment can counteract the clinical course of increasing obesity in PWS by maintaining the improved body composition brought during early treatment. SETTING: This was a multicenter prospective cohort study. METHODS: We have been following 60 prepubertal children for 8 years of continuous GH treatment (1 mg/m(2)/d ≈ 0.035 mg/kg/d) and used the same dual-energy x-ray absorptiometry machine for annual measurements of lean body mass and percent fat. RESULTS: After a significant increase during the first year of GH treatment (P < .0001), lean body mass remained stable for 7 years at a level above baseline (P < .0001). After a significant decrease in the first year, percent fat SD score (SDS) and body mass index SDS remained stable at a level not significantly higher than at baseline (P = .06, P = .14, resp.). However, body mass index SDSPWS was significantly lower after 8 years of GH treatment than at baseline (P < .0001). After 8 years of treatment, height SDS and head circumference SDS had completely normalized. IGF-1 SDS increased to +2.36 SDS during the first year of treatment (P < .0001) and remained stable since then. GH treatment did not adversely affect glucose homeostasis, serum lipids, blood pressure, and bone maturation. CONCLUSION: This 8-year study demonstrates that GH treatment is a potent force for counteracting the clinical course of obesity in children with PWS.

Smith-Lemli-Opitz syndrome and the DHCR7 gene.

Smith-Lemli-Opitz syndrome, a severe developmental disorder associated with multiple congenital anomalies, is caused by a defect of cholesterol biosynthesis. Low cholesterol and high concentrations of its direct precursor, 7-dehydrocholesterol, in plasma and tissues are the diagnostic biochemical hallmarks of the syndrome. The plasma sterol concentrations correlate with severity and disease outcome. Mutations in the DHCR7 gene lead to deficient activity of 7-dehydrocholesterol reductase (DHCR7), the final enzyme of the cholesterol biosynthetic pathway. The human DHCR7 gene is localised on chromosome 11q13 and its structure has been characterized. Ninety-one different mutations in the DHCR7 gene have been published to date. This paper is a review of the clinical, biochemical and molecular genetic aspects.

Novel mutations in the 7-dehydrocholesterol reductase gene of 13 patients with Smith--Lemli--Opitz syndrome.

Smith--Lemli--Opitz syndrome (SLOS) is caused by mutations in the DHCR7 gene leading to deficient activity of 7-dehydrocholesterol reductase (DHCR7; EC 1.3.1.21), the final enzyme of the cholesterol biosynthetic pathway, resulting in low cholesterol and high concentrations of its direct precursor 7-dehydrocholesterol in plasma and tissues. We here report mutations identified in the DHCR7 gene of 13 children diagnosed with SLOS by clinical and biochemical criteria. We found a high frequency of the previously described IVS8--1 G > C splice acceptor site mutation (two homozygotes, eight compound heterozygotes). In addition, 13 missense mutations and one splice acceptor mutation were detected in eleven patients with a mild to moderate SLOS-phenotype. The mutations include three novel missense mutations (W182L, C183Y, F255L) and one novel splice acceptor site mutation (IVS8--1 G > T). Two patients, homozygous for the IVS8--1 G > C mutation, presented with a severe clinical phenotype and died shortly after birth. Seven patients with a mild to moderate SLOS-phenotype disclosed compound heterozygosity of the IVS8--1 G > C mutation in combination with different novel and known missense mutations.

Simvastatin. A new therapeutic approach for Smith-Lemli-Opitz syndrome.

The Smith-Lemli-Opitz syndrome (SLOS) is caused by deficient Delta(7)-dehydrocholesterol reductase, which catalyzes the final step of the cholesterol biosynthetic pathway, resulting in low cholesterol and high concentrations of its direct precursors 7-dehydrocholesterol (7DHC) and 8DHC. We hypothesized that i) 7DHC and 8DHC accumulation contributes to the poor outcome of SLOS patients and ii) blood exchange transfusions with hydroxymethylglutaryl (HMG)-CoA reductase inhibition would improve the precursor-to-cholesterol ratio and may improve the clinical outcome of SLO patients. First, an in vitro study was performed to study sterol exchange between plasma and erythrocyte membranes. Second, several exchange transfusions were carried out in vivo in two SLOS patients. Third, simvastatin was given for 23 and 14 months to two patients. The in vitro results illustrated rapid sterol exchange between plasma and erythrocyte membranes. The effect of exchange transfusion was impressive and prompt but the effect on plasma sterol levels lasted only for 3 days. In contrast, simvastatin treatment for several months demonstrated a lasting improvement of the precursor-to-cholesterol ratio in plasma, erythrocyte membranes, and cerebrospinal fluid (CSF). Plasma precursor concentrations decreased to 28 and 33% of the initial level, respectively, whereas the cholesterol concentration normalized by a more than twofold increase. During the follow-up period all morphometric parameters improved. The therapy was well tolerated and no unwanted clinical side effects occurred. This is the first study in which the blood cholesterol level in SLOS patients is normalized with a simultaneous significant decrease in precursor levels. There was a lasting biochemical improvement with encouraging clinical improvement. Statin therapy is a promising novel approach in SLOS that deserves further studies in larger series of patients.

[Three hypotonic neonates with hypertrophic cardiomyopathy: Pompe's disease]. / Drie hypotone zuigelingen met een hypertrofische cardiomyopathie: de ziekte van Pompe.

Three neonatal patients, one girl and two boys, presented with infantile Pompe's disease. A generalized hypotonia with decreased tendon reflexes and heart failure due to hypertrophic cardiomyopathy dominated the clinical picture in all three; these symptoms are uniformly and characteristically present. This autosomal recessive glycogen storage disease is caused by a deficiency of lysosomal alpha-glucosidase. The diagnosis, suspected on the basis of the characteristic clinical picture and the results of simple laboratory tests, is made by measurement of the enzymatic activity or DNA analysis. Most patients die in their first year of life, no treatment being available.

Smith-Lemli-Opitz syndrome is caused by mutations in the 7-dehydrocholesterol reductase gene.

Smith-Lemli-Opitz syndrome is a frequently occurring autosomal recessive developmental disorder characterized by facial dysmorphisms, mental retardation, and multiple congenital anomalies. Biochemically, the disorder is caused by deficient activity of 7-dehydrocholesterol reductase, which catalyzes the final step in the cholesterol-biosynthesis pathway-that is, the reduction of the Delta7 double bond of 7-dehydrocholesterol to produce cholesterol. We identified a partial transcript coding for human 7-dehydrocholesterol reductase by searching the database of expressed sequence tags with the amino acid sequence for the Arabidopsis thaliana sterol Delta7-reductase and isolated the remaining 5' sequence by the "rapid amplification of cDNA ends" method, or 5'-RACE. The cDNA has an open reading frame of 1,425 bp coding for a polypeptide of 475 amino acids with a calculated molecular weight of 54.5 kD. Heterologous expression of the cDNA in the yeast Saccharomyces cerevisiae confirmed that it codes for 7-dehydrocholesterol reductase. Chromosomal mapping experiments localized the gene to chromosome 11q13. Sequence analysis of fibroblast 7-dehydrocholesterol reductase cDNA from three patients with Smith-Lemli-Opitz syndrome revealed distinct mutations, including a 134-bp insertion and three different point mutations, each of which was heterozygous in cDNA from the respective parents. Our data demonstrate that Smith-Lemli-Opitz syndrome is caused by mutations in the gene coding for 7-dehydrocholesterol reductase.

Pitfalls in measuring plasma cholesterol in the Smith-Lemli-Opitz syndrome.

Correct quantitative results for plasma cholesterol, 7-dehydrocholesterol (7-DHC), and 8-dehydrocholesterol (8-DHC) are invaluable for making the correct diagnosis in patients with the Smith-Lemli-Opitz syndrome (SLO) and for biochemical monitoring of these patients during therapy. The enzymatic method for cholesterol measurement based on cholesterol oxidase gives falsely high values for plasma cholesterol in samples from patients with SLO. Both 7-DHC and 8-DHC contribute substantially to the test result, given that they are accepted substrates of cholesterol oxidase. All cholesterol methods making use of this enzyme are expected to give unreliable results with plasma samples from SLO patients. Cholesterol values found with these methods may be low-normal in individual cases with SLO. Therefore, other techniques for measuring cholesterol, 7-DHC, and 8-DHC, e.g., gas chromatography, should be used for diagnosing these patients and for follow-up during therapy. However, a normal value for plasma cholesterol, as obtained by gas chromatography, does not exclude SLO. The diagnosis should always be confirmed or excluded by testing for the presence of high concentrations of 7-DHC and 8-DHC in plasma. We found that one patient with a severe form of the disease had a plasma cholesterol concentration of 20 micromol/L-to our knowledge, the lowest value ever recorded in a human being.

[Theophylline poisoning in children]. / Theofylline-intoxicatie bij kinderen.

Three infants aged 1, 3 and 9 months with severe theophylline intoxication are reported. Maximum serum theophylline concentrations were 65, 44 and 156 mg/l, respectively. Vomiting, agitation and tachycardia are the classical features. Seizures and cardiac arrhythmias suggest severe intoxication. The third patient underwent immediate peritoneal dialysis. All patients survived and recovered without sequelae. Haemoperfusion is considered to be the definite treatment for severe forms of theophylline intoxication.

[Smith-Lemli-Opitz syndrome; a special defect in cholesterol metabolism]. / Het Smith-Lemli-Opitz-syndroom; een bijzonder defect in het cholesterolmetabolisme.

In a male neonate dysmaturity, microcephalia, a high nasal bridge, a long philtrum, broad dental ridges, schisis of the palatum molle, retrognathia, a small penis with a chorda, a small scrotum, bilateral inguinal hernia and bilateral syndactyly of the second and third toes were observed. The presence of the Smith-Lemli-Opitz (SLO) syndrome was suspected. By gas chromatography a severely decreased plasma cholesterol level (0.27 mmol/l) was found and an increased plasma 7-dehydrocholesterol level (0.24 mmol/l). The SLO syndrome is caused by a block in the cholesterol biosynthesis due to the autosomal recessive deficiency of 7-dehydrocholesterol reductase. The patient's condition improved with use of a cholesterol-enriched diet.