Prevalence and severity of anthelmintic resistance in ovine gastrointestinal nematodes in Australia (2009-2012).

OBJECTIVE: This study aimed to provide an indication of the prevalence and severity of anthelmintic resistance (AR) in the Australian sheep industry by compiling the results of faecal worm egg count reduction tests (FECRTs). METHODS: Government and private parasitology laboratories, pharmaceutical companies and veterinarians known to have conducted FECRTs were asked to provide results that conformed to Australian and New Zealand standard diagnostic procedures. RESULTS: Data were available from a total of 390 tests, with larval differentiation conducted in 222 cases. Pooled results from all states for the macrocyclic lactone (ML) class showed a lower prevalence of AR against combined species for moxidectin (54%) compared with abamectin (77%) and ivermectin (87%). Analysis by state revealed higher levels of ML-resistant Teladorsagia sp. in Tasmania and Western Australia than in other states and ML-resistant Haemonchus sp. was more frequently detected in New South Wales. CONCLUSION: This compilation of results of FECRTs conducted by Australian parasitology laboratories in 2009-12 showed widespread AR of the common sheep nematodes (Teladorsagia, Trichostrongylus and Haemonchus) to all broad-spectrum anthelmintics, with the exception of monepantel, whether used singly or in combination.

Effective control of a suspected cyromazine-resistant strain of Lucilia cuprina using commercial spray-on formulations of cyromazine or dicyclanil.

OBJECTIVE: To demonstrate the protection of Merino sheep from flystrike by Lucilia cuprina with cyromazine or dicyclanil in an implant study and in the field. METHODS: In the implant study, sheep were treated with cyromazine or dicyclanil and implanted with 1st-stage larvae from a newly isolated field strain of L. cuprina (CYR-LS) or a reference strain (DZR50), then assessed over 3 days and compared with the implants on untreated control sheep. In the field study, weaner lambs were treated with cyromazine or dicyclanil and monitored weekly for flystrike over 18 weeks of grazing on the same farm from which the L. cuprina were isolated. RESULTS: Implant study: cyromazine (6%) provided effective protection against CYR-LS and DZR50 L. cuprina for a minimum of 13 and 10 weeks, respectively. Dicyclanil (5%) provided at least 18 weeks' protection against both strains. Field study: only 1 of 386 lambs in the cyromazine-treated group was struck in the first 14 weeks of the trial. No strikes occurred in the 198 sheep treated with dicyclanil (5%). Rainfall, temperature and flytrap data indicated consistent fly pressure during the study. CONCLUSIONS: Based on the results of these studies, there was no evidence of reduced susceptibility to cyromazine or dicyclanil and the periods of protection of sheep against L. cuprina were unaffected and consistent with the registered label claims.

Translation of H. contortus and T. colubriformis from egg to establishment in grazing sheep is unaffected by rainfall timing, rainfall amount and herbage height under conditions of high soil moisture in the Northern Tablelands of NSW.

A field experiment was conducted at Armidale in the Northern Tablelands of NSW, Australia to determine the effects of simulated rainfall amount (0, 12 and 24 mm), rainfall timing (days -1, 0 and 3 relative to plot contamination) and herbage height (4 and 12 cm), on translation of Haemonchus contortus and Trichostrongylus colubriformis from egg to established stages in grazing sheep under conditions of high soil moisture (22-23%). The experiment was conducted in summer when temperature was not anticipated to be a limiting factor for development success. Development success was assessed using tracer sheep and expressed as percentage recovery of parasitic stages relative to egg output on pasture (translation%). For both species, translation (0.11% H. contortus; 0.55% T. colubriformis) was observed in the absence of simulated rainfall and was unaffected by treatment effects of rainfall amount and timing, and herbage height. We suggest that soil moisture (>20%) alone was sufficient to support development and translation (from eggs to parasitic stages in the gut of tracer animals) of these species which contrasts with expectations for development success on dry soils. These findings identify the importance of taking soil moisture into account when predicting the likely effects of rainfall and herbage height on development to L3 and ultimately in predictive epidemiological models of ovine gastrointestinal nematodiasis.

Soil moisture modulates the effects of the timing and amount of rainfall on faecal moisture and development of Haemonchus contortus and Trichostrongylus colubriformis to infective third stage larvae.

Recent experiments on the effects of rainfall and/or soil moisture (SM) on development of sheep gastro-intestinal nematodes to infective L3 stage have used soil of relatively low moisture content in small experimental samples that dry out faster than field soil. To determine whether higher and more sustained SM content modulates the effects of rainfall amount and timing on faecal moisture (FM) and development of H. contortus and T. colubriformis to infective third stage larvae (L3), a climate-controlled chamber experiment was conducted. It was designed to test the effects of rainfall amount (0, 12 and 24 mm), rainfall timing (days -1, 0 and 3 relative to faecal deposition) and soil moisture maintained at 10, 20 and 30% on these variables. Total recovery of L3 14 days after faecal deposition was significantly affected by SM, rainfall timing and their interaction (P<0.01), but not by rainfall amount or species or other two-way interactions. Recovery of L3 was maximal (28%) with a SM treatment of 30% and simulated rainfall on day 3. Faecal moisture was significantly affected by collection day, SM treatment, rainfall amount and rainfall timing with significant interaction between many of these effects (P<0.05). A positive linear association between FM and total L3 recovery was strongest on day 4 after faecal deposition (R(2)=0.64, P<0.001) for H. contortus and day 6 (R(2)=0.78, P<0.001) for T. colubriformis. Overall the results show that SM is able to modulate the effects of rainfall timing and amount with increased SM acting to broaden the window of opportunity for the free-living stages to respond to post deposition rainfall to complete development to L3. If SM is maintained in the range 10-30%, the reported benefits of early rainfall (days -1 and 0) of up to 24 mm appear to be negated with later rainfall (day 3) proving more beneficial. These results require field confirmation.

Soil moisture influences the development of Haemonchus contortus and Trichostrongylus colubriformis to third stage larvae.

Two climate chamber experiments were conducted to determine the effect of varying initial soil moisture (0, 10 and 15%), simulated rainfall amount (0, 12 and 24 mm) and simulated rainfall timing (days -1, 0 and 3 relative to faecal deposition) on development (day 14) of Haemonchus contortus and Trichostrongylus colubriformis to the third stage larvae (L3) and faecal moisture (FM). Increasing initial soil moisture content from 0 to 10 or 15% led to higher recovery of total L3 (P<0.001). Total L3 recovery increased with each level of simulated rainfall (P<0.001) in the ascending order of 0, 12 and 24 mm. There was an interaction between the effects of initial soil moisture and simulated rainfall amount on the recovery of total L3, showing that the benefit of increased simulated rainfall lessened with increasing soil moisture. Simulated rainfall on the day of deposition resulted in higher recovery of L3 (P<0.001) than simulated rainfall on other days. FM on day 3 relative to faecal deposition was best associated with recovery of total H. contortus and T. colubriformis L3 (R(2)=0.32-0.46), reinforcing the importance of sufficient moisture soon after faecal deposition. The effects of initial soil moisture, and the amount and timing of simulated rainfall on development to L3 were largely explained by changes to FM and soil moisture values within 4 days relative to faecal deposition. These results highlight the influence of soil moisture and its interaction with rainfall on development of H. contortus and T. colubriformis to L3. Consequently we recommend that soil moisture be given greater importance and definition in the conduct of ecological studies of parasitic nematodes, in order to improve predictions of development to L3.

Effect of simulated rainfall timing on faecal moisture and development of Haemonchus contortus and Trichostrongylus colubriformis eggs to infective larvae.

Three climate-controlled chamber experiments were conducted to determine the effect of 32 mm simulated rainfall applied prior to (days -4 to -1) or after (days 0-7) faecal deposition and as a single (32 mm) or split (2 × 16 mm) application on faecal moisture (FM) and development of H. contortus and T. colubriformis to third stage infective larvae (L3). The timing of simulated rainfall regulated extra-pellet L3 recovery for H. contortus (P<0.05) but not T. colubriformis. Recovery of L3 was highest (P<0.05) when simulated rainfall was applied on the day of deposition followed by days -1, 1 and 2, which resulted in similar but lower development success rates. Recovery of intra-pellet T. colubriformis L3 was two-fold greater (P=0.008) than for H. contortus and was higher (P=0.007) following simulated rainfall on days 0 and 1 than on other days. There was a positive association between FM and total L3 recovery indicating the importance of FM in the period 48-72 h (H. contortus) and 72-96 h (T. colubriformis) after deposition. Simulated rainfall on the day prior to deposition was as effective in supporting total L3 recovery as application on days 1 or 2 and this effect could be predicted through FM. This highlights the importance of soil in transferring moisture to the faecal pellet. The importance of precedent rainfall and soil moisture in determining the development success of H. contortus and T. colubriformis, in addition to the general effects of the timing of simulated rainfall, need to be accommodated in grazing management programs to combat these species.

Environmental stress alters genetic regulation of novelty seeking in vervet monkeys.

Considerable attention has been paid to identifying genetic influences and gene-environment interactions that increase vulnerability to environmental stressors, with promising but inconsistent results. A nonhuman primate model is presented here that allows assessment of genetic influences in response to a stressful life event for a behavioural trait with relevance for psychopathology. Genetic and environmental influences on free-choice novelty seeking behaviour were assessed in a pedigreed colony of vervet monkeys before and after relocation from a low stress to a higher stress environment. Heritability of novelty seeking scores, and genetic correlations within and between environments were conducted using variance components analysis. The results showed that novelty seeking was markedly inhibited in the higher stress environment, with effects persisting across a 2-year period for adults but not for juveniles. There were significant genetic contributions to novelty seeking scores in each year (h(2) = 0.35-0.43), with high genetic correlations within each environment (rhoG > 0.80) and a lower genetic correlation (rhoG = 0.35, non-significant) between environments. There were also significant genetic contributions to individual change scores from before to after the move (h(2) = 0.48). These results indicate that genetic regulation of novelty seeking was modified by the level of environmental stress, and they support a role for gene-environment interactions in a behavioural trait with relevance for mental health.

A multi-species model to assess the effect of refugia on worm control and anthelmintic resistance in sheep grazing systems.

OBJECTIVE: Develop a computer simulation model that uses daily meteorological data and farm management practices to predict populations of Trichostrongylus colubriformis, Haemonchus contortus and Teladorsagia (Ostertagia) circumcincta and the evolution of anthelmintic resistance within a sheep flock. Use the model to explore if increased refugia, provided by leaving some adult sheep untreated, would delay development of anthelmintic resistance without compromising nematode control. PROCEDURES: Compare model predictions with field observations from a breeding flock in Armidale, NSW. Simulate the impact of leaving 1-10% of adult sheep untreated in diverse sheep-grazing systems. RESULTS: Predicted populations of Tr. colubriformis and T. circumcincta were less than those observed in the field, attributed to nutritional stress experienced by the sheep during drought and not accounted for by the model. Observed variation in faecal egg counts explained by the model (R(2) ) for these species was 40-50%. The H. contortus populations and R(2) were both low. Leaving some sheep untreated worked best in situations where animals were already grazing or were moved onto pastures with low populations of infective larvae. In those cases, anthelmintic resistance was delayed and nematode control was maintained when 1-4% of adult stock remained untreated. CONCLUSIONS: In general, the model predicted that leaving more than 4% of adults untreated did not sufficiently delay the development of anthelmintic resistance to justify the increased production risk from such a strategy. The choice of a drug rotation strategy had an equal or larger effect on nematode control, and selection for resistance, than leaving 1-10% of adults untreated.

Minimising the development of anthelmintic resistance, and optimising the use of the novel anthelmintic monepantel, for the sustainable control of nematode parasites in Australian sheep grazing systems.

OBJECTIVE: To compare the risk of different treatment scenarios on selecting for anthelmintic resistance on Australian sheep farms. DESIGN: A computer simulation model predicted populations of Trichostrongylus colubriformis, Haemonchus contortus or Teladorsagia (Ostertagia) circumcincta, and the frequency of anthelmintic resistance genes. METHOD: Nematode populations and the progression of drug resistance for a variety of treatment options and management practices in sheep-rearing areas of Western Australia (WA), Victoria (VIC) and New South Wales (NSW) were simulated. A scoring system was devised to measure the success of each option in delaying resistance to each anthelmintic and in controlling nematode populations. RESULTS: The best option at all sites was combining the new anthelmintic (monepantel) with a triple mixture of benzimidazole, levamisole and abamectin (COM). The next best option was: in NSW, rotation at each treatment between monepantel, moxidectin and COM; in VIC, rotation at each treatment between monepantel and COM; and in WA, rotation at each treatment between monepantel (used in winter) and COM or moxidectin (used in summer-autumn). In WA, rapid selection for resistance occurred as a consequence of summer-autumn treatments; however, if a small percentage of adult stock were left untreated then this selection could be greatly reduced. Despite purposely assuming relatively high resistance to benzimidazole and levamisole, COM was still effective in controlling worms and delaying resistance. CONCLUSIONS: Because of cost constraints, it may not be feasible or profitable for producers to always use the combination of all drugs. However, the second- and third-best options still considerably slowed the development of anthelmintic resistance.

The relative contributions of T. colubriformis, T. vitrinus, T. axei and T. rugatus to sheep infected with Trichostrongylus spp. on the northern tablelands of New South Wales.

This survey was designed to determine the spatial and temporal distribution and the relative contributions of Trichostrongylus colubriformis, Trichostrongylus vitrinus, Trichostrongylus axei and Trichostrongylus rugatus to sheep infected with Trichostrongylus spp. on the northern tablelands of NSW. Thirty completed larval cultures were collected from a commercial parasitology laboratory servicing the northern tablelands of NSW between June and December 2007. Cultures were selected at random from farms within the study area whenever the combined results of faecal worm egg counting and coproculture indicated >200 Trichostrongylus spp. eggs per gram and >40% Trichostrongylus spp. respectively. Selection of cultures was constrained to prevent multiple samples from a single grazing property. Larval cultures were stored at 4 degrees C and subsequently used to artificially infect GIN-free sheep which were sacrificed for the collection of gut contents at 3 weeks post-infection. Abomasal contents were examined for the presence of T. axei. From the anterior small intestine 100 adult male Trichostrongylus spp. per animal were identified to species (T. colubriformis, T. vitrinus or T. rugatus) according to spicule morphology. T. colubriformis was the most prevalent Trichostrongylus species (present in 100% of the samples) as anticipated in a summer rainfall region. T. vitrinus was present in 20% of the samples whilst T. rugatus was present in only 10% of the samples, yet when present comprised a much higher proportion of the total Trichostrongylus population than has previously been reported. In an unexpected result, T. axei was not identified in any of the samples collected. The epidemiological basis for these results and the implications for gastro-intestinal nematode control are discussed.

Comparison of strategies to provide lambing paddocks of low gastro-intestinal nematode infectivity in a summer rainfall region of Australia.

A replicated field experiment using nine 2ha paddocks was designed to compare the efficacy of 3 management strategies to prepare spring lambing paddocks of low gastro-intestinal nematode (GIN) infectivity. The management treatments were designed to provide the same overall stocking rate over the lambing paddock preparation period (Phase 1, 16 January-9 June, 2006). The first treatment involved two 21-day periods of intensive grazing with drenched wethers in Jan-Feb, and in late March (Smartgraze summer rainfall, SGSR). The second treatment was industry standard practice of continuous grazing of adult sheep over the entire preparation period (continuous sheep, CS) and the third treatment was industry best practice of continuous grazing of adult cattle (continuous cattle, CC). Phase 2 of the experiment (14 August-12 December, 2006) tested the efficacy of the paddock preparation treatments. Single-bearing ewes (n=10 per paddock) were introduced on 14 August following an effective short acting anthelmintic treatment. Lambing commenced 2 weeks later on the 25th of August with lamb marking at 7 weeks and weaning at 15 weeks when the experiment was terminated. Tracer sheep (n=2) were run in each of the paddocks for 2 weeks at the start of Phase 1, and at the start and conclusion of Phase 2 to assess pasture GIN contamination. Total worm counts in tracers were reduced by 97.7% (SGSR), 96.9% (CC) and 88.5% (CS) between the start of the experiment and the introduction of lambing ewes. Between the start of the experiment and weaning, total reductions were 87.9% (SGSR), 85.6% (CC) and 26% (CS). Worm egg counts of ewes and lambs grazing SGSR or CC paddocks were significantly lower than those grazing CS paddocks. As a consequence ewes grazing CS paddocks required anthelmintic treatment at both marking and weaning and their lambs at weaning, whereas no anthelmintic treatments were required for ewes or lambs on SGSR paddocks. Ewes and lambs grazing paddocks prepared with SGSR and CC were significantly heavier at weaning than those grazing paddocks prepared with CS, despite requiring fewer anthelmintic treatments. This experiment demonstrates that an understanding of regional GIN epidemiology can be employed to prepare pastures of very low infectivity in sheep only systems (SGSR) providing parasitological and production benefits equivalent to those obtained by grazing non-host species, in this case mature cattle (CC). Implications of these strategies for the development of anthelmintic resistance are discussed.

Availability of gastro-intestinal nematode larvae to sheep following winter contamination of pasture with six nematode species on the Northern Tablelands of New South Wales.

This experiment was designed to determine the infective consequences of winter pasture contamination by sheep infected with 6 species of trichostrongylid gastro-intestinal nematode (GIN) at Armidale in the New England region of NSW. Ten helminthologically inert pasture plots were contaminated using 'donor' sheep harbouring artificial infections of Haemonchus contortus, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Trichostrongylus axei, Nematodirus spathiger and Teladorsagia circumcincta. A single plot was contaminated in March to serve as a positive control and three plots in each of the winter months of June, July or August of 2007. Weekly assessments of 24 h faecal output and worm egg count of all donor sheep, combined with differentiation of larval cultures enabled calculation of total egg deposition per plot for each GIN species for each month of contamination. All plots were provided with supplemental spray irrigation sufficient to remove desiccation as a cause of non-development. The infective consequence of each monthly contamination was assessed by grazing each plot with two tracer sheep for the last 14 days of each month following contamination until a final grazing in November. Translation for each GIN species was expressed as the percentage of eggs deposited translating to worms counted in tracer sheep. The GIN parasites fell into two distinct groups differing greatly in translational success. Translation of egg to establishment in the tracer host was ineffective for H. contortus, T. axei and T. colubriformis but effective for T. vitrinus, T. circumcincta and N. spathiger. Overall mean total translation for each of these species throughout the experiment was respectively 0.00%, 0.00%, 0.00%, 0.34%, 0.45% and 0.48%. We conclude that winter contamination of pastures in this region with eggs of the latter 3 species is capable of impacting on the health of sheep subsequently grazing these pastures. Where H. contortus and T. colubriformis predominate, paddocks selected for spring lambing may be grazed safely over the winter months without contributing significantly to pasture contamination. These findings are particularly relevant to the preparation of clean spring lambing paddocks in this region using grazing management.

Novel mutations in Myoclonin1/EFHC1 in sporadic and familial juvenile myoclonic epilepsy.

BACKGROUND: Juvenile myoclonic epilepsy (JME) accounts for 3 to 12% of all epilepsies. In 2004, the GENESS Consortium demonstrated four missense mutations in Myoclonin1/EFHC1 of chromosome 6p12.1 segregating in 20% of Hispanic families with JME. OBJECTIVE: To examine what percentage of consecutive JME clinic cases have mutations in Myoclonin1/EFHC1. METHODS: We screened 44 consecutive patients from Mexico and Honduras and 67 patients from Japan using heteroduplex analysis and direct sequencing. RESULTS: We found five novel mutations in transcripts A and B of Myoclonin1/EFHC1. Two novel heterozygous missense mutations (c.755C>A and c.1523C>G) in transcript A occurred in both a singleton from Mexico and another singleton from Japan. A deletion/frameshift (C.789del.AV264fsx280) in transcript B was present in a mother and daughter from Mexico. A nonsense mutation (c.829C>T) in transcript B segregated in four clinically and seven epileptiform-EEG affected members of a large Honduran family. The same nonsense mutation (c.829C>T) occurred as a de novo mutation in a sporadic case. Finally, we found a three-base deletion (-364--362del.GAT) in the promoter region in a family from Japan. CONCLUSION: Nine percent of consecutive juvenile myoclonic epilepsy cases from Mexico and Honduras clinics and 3% of clinic patients from Japan carry mutations in Myoclonin1/EFCH1. These results represent the highest number and percentage of mutations found for a juvenile myoclonic epilepsy causing gene of any population group.

Application of topical mitomycin C to the base of shave-removed keloid scars to prevent their recurrence.

BACKGROUND: Keloid scars are formed by over-activity of fibroblasts producing collagen and they cause significant morbidity both from their appearance and from their symptoms. Existing treatments are often unsatisfactory. Topical mitomycin C is known to inhibit fibroblast proliferation. OBJECTIVES: To determine whether application of mitomycin C to the base of shave-removed keloids would prevent their recurrence. METHODS: Ten patients had all or part of their keloid shave-removed. After haemostasis topical mitomycin C 1 mg mL(-1) was applied for 3 min. This application was repeated after 3 weeks. The keloids were photographed before treatment and the patients were reviewed every 2 months for a total of 6 months when a final photograph of the keloid site was taken. The patients and the Clinical Trials Unit staff scored the outcome on a linear analogue scale of 0-10, where 0 = disappointed and 10 = delighted. The pretreatment and 6-month post-treatment photographs were also assessed by two dermatologists who were not involved in the clinical trial. RESULTS: Four of the 10 patients were delighted with the outcome of treatment and only one was disappointed. On average there was an 80% satisfied outcome. CONCLUSIONS: This new treatment of keloids has been shown to be effective in the majority of patients but further studies are required to confirm this benefit.

SNPing away at candidate genes.

We develop regression methodology to identify subsets of single nucleotide polymorphisms (SNPs) within candidate genes related to quantitative traits and apply our methods to the simulated Genetic Analysis Workshop (GAW) 12 data set. In the data set we find 694 SNP loci with minimum allele frequencies of at least 0.01. We assume an additive casual model between these SNPs and all five quantitative traits. After initial screening using one-way analysis of variance, we employ a computationally efficient, simulated annealing algorithm to select among all possible subsets of SNP loci, using a generalization of Mallows' Cp as our optimality criterion. The simple transition kernel we develop evaluates new subsets in O(1), by requiring just three arithmetic operations to calculate the proposed RSS based on the Gauss-Jordan pivot. We identify an SNP loci located at 6-5782 related to traits 2 and 3 and several sites on gene 2 related to trait 5 using a subsample of 1,000 individuals and the full data set (n = 8,250) for comparison.

Macrocephaly in autism and other pervasive developmental disorders.

To assess the prevalence of macrocephaly (head circumference > or = 1.88 standard deviations above normative data for age and sex or > 97th centile) in autism and other pervasive developmental disorders, 41 children with autism, and a comparison group of 21 children with tuberous sclerosis complex (TSC) or an unspecified seizure disorder were studied. Familiality of head circumference was also assessed from measurements of 133 first-degree relatives. Significantly higher rates of macrocephaly were found in probands with autism (12.2%) and their first-degree relatives (15.5%) when compared against a published normative sample. The incidence of macrocephaly in the comparison group of probands with TSC and seizure disorder (9.5%) and their first-degree relatives (8.3%) was higher than normative data as well, although the relation between macrocephaly and autism was more pronounced. Head circumference and extreme scores reflecting macrocephaly were moderately heritable in the present sample (H2 = 0.47). The increased prevalence of macrocephaly in relatives of children with autism compared with control children suggests that this characteristic may be a familial risk factor in the pathogenesis of autism.

Search for a gene x environment interaction: G x E hunt.

We developed a method to identify gene x environment interactions (G x Es). To test this method in the simulated data (Problem 2, GAW11), we first identified an environmental factor (E1) that was associated with the simulated disorder. We stratified affected sibling pairs (ASPs) into two groups, those concordant for the presence of E1 and those concordant for the absence of E1. We then localized genes on chromosomes 3 and 5 using identity-by-descent (IBD) sharing rates among ASPs. Because the stratified IBD sharing rates are independent of the environmental factor if there is no G x E, we inferred the existence of a G x E near loci 3G44 and 3G45 by testing whether the proportion of ASPs sharing no alleles IBD differed among the two groups.

Transmission of primary nocturnal enuresis and attention deficit hyperactivity disorder.

Primary nocturnal enuresis (PNE) is a prevalent disorder among children with a complex mode of inheritance. Family, twin, and linkage studies have provided evidence that genetic factors underlie the familiality of PNE. Linkage investigations support the hypothesis that PNE is heterogeneous, and the genetic heterogeneity may be reflected in co-morbid clinical conditions such as attention deficit hyperactivity disorder (ADHD). This study used a family study method and examined the transmission of PNE in relatives of PNE and control probands with and without ADHD, to determine if these disorders co-occur due to common genetic susceptibilities or other, i.e. non-genetic, reasons. This study concluded that the pattern of inheritance found is consistent with the independent transmission of PNE and ADHD.