Masayuki Imaeda

Genetic influences on the broad spectrum of autism: study of proband-ascertained twins.

An investigation of genetic structures underlying autistic traits was performed with samples from twins for which at least one proband had been ascertained as having autism spectrum disorders (ASDs) in our catchment area. In order to adjust for recent concepts of autism, we employed criteria for the broad spectrum of disease and the childhood autism rating scale (CARS) for quantitative assessment. The CARS test was performed on 45 twin pairs (19 monozygotic, 26 dizygotic) detected with a regional routine screening system. The obtained CARS scores were subjected to structural equation modeling (SEM), incorporating sex differences for each causal influence ascertainment correction, using the Mx software. A best fitting model of causal influences on autistic traits measured continuously, incorporating additive genetic (A) and non‐shared environmental influences (E), was generated. With this AE model, the estimated heritability was 0.73 for males and 0.87 for females, based on the continuous CARS scores. There was no evidence for the existence of sex‐specific genetic influences. Autistic traits were highly heritable in twins with even broad spectrum of autism, corresponding to the results of early studies based on classical autism. Additive genetic factors were more influential in females than males.

Population and family studies of dihydropyrimidinuria: Prevalence, inheritance mode, and risk of fluorouracil toxicity

To evaluate the prevalence of dihydropyrimidinuria (DHPuria), we analyzed urine samples from 21,200 healthy Japanese infants, and found two cases of DHPuria without clinical symptoms. Based on this result, we estimated the prevalence to be approximately 1/10,000 births in Japan. In addition, we analyzed pyrimidine catabolism on a previously reported family with an adult DHPuria case. We newly identified the sister of the propositus as the second case of DHPuria in this family, because she excreted large amounts of dihydrouracil and dihydrothymine. The parents and the child of the propositus showed slight increases of dihydrouracil and dihydrothymine. This is the first family with 2 cases of DHPuria, indicating that DHPuria is an inherited condition. To determine the inheritance of DHPuria in this family and to examine the risk of 5-fluorouracil (5-FU) toxicity, a uracil loading test was performed on the parents. Urinary dihydrouracil concentrations in the parents after the loading were several times higher than those in normal control persons, the finding being consistent with DHPuria heterozygotes. This, along with data on the propositus, his sister, and his child, indicates that DHPuria is an autosomal recessive condition. In addition, DHPuria homozygotes may have a high risk of 5-FU toxicity, while the risk is relatively low in heterozygotes.

Dihydropyrimidinuria: the first case in Japan.

Dihydropyrimidinuria (McKusick 222748) is a recently described disorder of pyrimidine metabolism that presents neurological symptoms different in degree. Only two cases have been reported to date (Duran et al, 1991; Henderson et al, 1993). The patients with dihydropyrimidinuria excrete large amount of dihydrouracil and dihydrothymine, and moderate amount of uracil and thymine in urine. Therefore this disease is thought to be caused by a deficiency of dihydropyrimidine amidohydrolase (DHPase; EC 3.5.2.2), the second step of pyrimidine base catabolism. The first case, reported by Duran et al (1991), was hospitalized for convulsion and disturbed consciousness at the age of 8 weeks, but whose subsequent development had been normal. The second case reported by Henderson et al (1993) presented severe developmental delay. These two patients were discovered by the urinary gas chromatography mass spectrometry (GC-MS) analysis for the neurological sick children. We report here another case of dihydropyrimidinuria which is the first case in Japan and probably the third worldwide. We discovered her by using high-performance liquid chromatography (HPLC) at the mass screening program.

Urinary Screening for Pyrimidine Metabolism Disorders

Pyrimidine chemotherapy agent such as 5-FU are used widely but can occasionally cause serious adverse reactions in patients with pyrimidine metabolism disorders. The screening method which entailed measuring dihydropyrimidine dehydro- genase activity (DPD) has been reported. This method is acceptable with small groups, but difficulties arise when dealing with large populations owing to the complicated procedure for measuring enzyme activity. We have studied the urinary screening method using high-performance liquid chromatograpy, which is acceptable with large groups.1 This method can diagnose not only dihydropyrimidine dehydrogenase deficiency but also dihydropyrimidinuria. Using this method, we have analyzed urinary dihydrouracil (DHU) and uracil concentrations in 167 healthy adults and 966 patients with malignancy, hypertension, cerebral infarction, etc. In order to establish the reference ranges of urinary pyrimidine, we used “log (concentration)”. Additionally, we calculated dihydrouracil/uracil ratio, which seemed to be reflected of DPD activity.

Concordance of DSM‐5 and DSM‐IV‐TR classifications for autism spectrum disorder

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM‐5) was published in May 2013. Autism spectrum disorder (ASD) has been structured for the three subtypes of pervasive developmental disorder (PDD), but the number of impairment in social and communication dimension is not stated.

A failure to confirm the effectiveness of a brief group psychoeducational program for mothers of children with high-functioning pervasive developmental disorders: a randomized controlled pilot trial

Objective The purpose of this study was to examine the effectiveness of group psychoeducation to relieve the psychological distress of mothers of children with high-functioning pervasive developmental disorders (HFPDD) and to improve the behaviors of the children. Methods Seventy-two mothers of preschool outpatients with HFPDD were randomly assigned to a four-session brief group psychoeducational program (GP). The sessions were held every second week in addition to the usual treatment (GP + treatment as usual [TAU] group), or to a TAU-alone group. The primary outcome was self-reported symptoms of maternal mental health as assessed using the 28-item General Health Questionnaire (GHQ-28) at 21 weeks post-randomization (week 21). The GHQ-28 at the end of the intervention (week 7), Aberrant Behavior Checklist (ABC) for the behavior of the children, the Zarit Burden Interview (ZBI), and the Medical Outcomes Study 36-item Short Form Health Survey (SF-36) were carried out at weeks 7 and 21. We tested the group effects with the interaction between the intervention and the evaluation points. Results The GHQ-28 score at week 21 was significantly higher in the GP + TAU group as compared to that in the TAU-alone group, indicating a greater improvement in the TAU-alone group. There was no evidence that GP + TAU led to a greater improvement of maternal mental health than TAU-alone at week 7. Similarly, no evidence was obtained to indicate that GP + TAU led to a reduction in the ABC or ZBI scores by week 7 or 21. The adjusted scores for the RF (role emotional) and MH (mental health) subscales of the SF-36 at week 21 were also significantly lower in the GP + TAU group, indicating a similar tendency to that of the change of the GHQ-28 score at week 21. Conclusion The psychoeducational program did not alleviate maternal distress, aberrant behaviors of the children, or caregiver burden.

Urinary uracil in female patients with ornithine transcarbamylase deficiency

Abstract Background : Female patients with ornithine transcarbamylase deficiency (OTCD) show a wide range of clinical severity, from asymptomatic to lethal hyperammonemia. It is important to establish a simple method to distinguish symptomatic from asymptomatic patients.