Myotonic dystrophy type 1 is caused by the expansion of a CTG repeat in the 3' UTR of the DMPK gene. A length exceeding 50 CTG triplets is pathogenic. Intermediate alleles with 35-49 triplets are not disease-causing but show instability in intergenerational transmissions. We report on the identification of multiple patients with different patterns of CCG and CTC interruptions in the DMPK CTG repeat tract that display unique intergenerational instability. In patients bearing interrupted expanded alleles, the location of the interruptions changed dramatically between generations and the repeats tended to contract. The phenotype for these patients corresponded to the classical form of the disease, but in some cases without muscular dystrophy and possibly with a later onset than expected. Symptomatic patients bearing interrupted intermediate length repeat tracts were also identified, although the role of the interruptions in their phenotype remains unclear. The identification of interruptions in the DMPK repeat has important consequences for molecular genetic testing where they can lead to false negative conclusions.

Most genes associated with neurodevelopmental disorders (NDDs) were identified with an excess of de novo mutations (DNMs) but the significance in case–control mutation burden analysis is unestablished. Here, we sequence 63 genes in 16,294 NDD cases and an additional 62 genes in 6,211 NDD cases. By combining these with published data, we assess a total of 125 genes in over 16,000 NDD cases and compare the mutation burden to nonpsychiatric controls from ExAC. We identify 48 genes (25 newly reported) showing significant burden of ultra-rare (MAF < 0.01%) gene-disruptive mutations (FDR 5%), six of which reach family-wise error rate (FWER) significance (p < 1.25E−06). Among these 125 targeted genes, we also reevaluate DNM excess in 17,426 NDD trios with 6,499 new autism trios. We identify 90 genes enriched for DNMs (FDR 5%; e.g., GABRG2 and UIMC1); of which, 61 reach FWER significance (p < 3.64E−07; e.g., CASZ1). In addition to doubling the number of patients for many NDD risk genes, we present phenotype–genotype correlations for seven risk genes (CTCF, HNRNPU, KCNQ3, ZBTB18, TCF12, SPEN, and LEO1) based on this large-scale targeted sequencing effort.

Objective: The aim of our study was to examine odor detection thresholds and odor identification in autistic subjects. Methods:Thirty-five patients with Asperger"s syndrome and high functioning autism (mean age 10.8 ± 3.6 years; 31 boys) were compared with 35 healthy control subjects (mean age 10.4 ± 2.4 years; 28 boys). There were no significant differences between groups with regard to mean age (p = 0.598) and gender proportion (p = 0.324). Olfactory testing used the Sniffin" Sticks test (Threshold and Identification parts only).Results: Participants with Asperger"s syndrome and high functioning autism, in comparison with healthy controls, were significantly impaired relative to odor detection thresholds (6.3 ± 3.1 vs. 7.9 ± 2.0; p = 0.025). Autistic participants were significantly better in correctly identifying the odor of an orange (94% vs. 63%; p < 0.05) and significantly worse at correctly identifying the odor of cloves (40% vs. 74%; p < 0.05). With regard to identification of fourteen other substances, there were no significant differences. There was no significant difference between autistic and control subjects on the total score of olfactory identification (p = 0.799). Odor identification ability (as expressed by this total score) correlated significantly with age in the control group (p = 0.049) but not in the autism group (p = 0.103). Conclusions:We found impaired odor detection and almost normal odor identification in children with autism. Implications for further research are discussed.

The aim of the study was to investigate the potential association of epilepsy and EEG abnormalities with autistic regression and mental retardation. We examined a group of 77 autistic children (61 boys, 16 girls) with an average age of 9.1 +/- 5.3 years. Clinical interview, neurological examination focused on the evaluation of epilepsy, IQ testing, and 21-channel EEG (including night sleep EEG recording) were performed. Normal EEGs were observed in 44.4% of the patients, non-epileptiform abnormal EEGs in 17.5%, and abnormal EEGs with epileptiform discharges in 38.1% of the patients. Epilepsy was found in 22.1% of the subjects. A history of regression was reported in 25.8% of the patients, 54.8% of the sample had abnormal development during the first year of life, and 79.7% of the patients were mentally retarded. Autistic regression was significantly more frequent in patients with epilepsy than in non-epileptic patients (p = 0.003). Abnormal development during the first year of life was significantly associated with epileptiform EEG abnormalities (p = 0.014). Epilepsy correlated significantly with mental retardation (p = 0.001). Although the biological basis and possible causal relationships of these associations remain to be explained, they may point to different subgroups of patients with autistic spectrum disorders.

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