Long non-coding RNAs (lncRNAs) can be important components in gene-regulatory networks 1 , but the exact nature and extent of their involvement in human Mendelian disease is largely unknown. Here we show that genetic ablation of a lncRNA locus on human chromosome 2 causes a severe congenital limb malformation. We identified homozygous 27-63-kilobase deletions located 300 kilobases upstream of the engrailed-1 gene (EN1) in patients with a complex limb malformation featuring mesomelic shortening, syndactyly and ventral nails (dorsal dimelia). Re-engineering of the human deletions in mice resulted in a complete loss of En1 expression in the limb and a double dorsal-limb phenotype that recapitulates the human disease phenotype. Genome-wide transcriptome analysis in the developing mouse limb revealed a four-exon-long non-coding transcript within the deleted region, which we named Maenli. Functional dissection of the Maenli locus showed that its transcriptional activity is required for limb-specific En1 activation in cis, thereby fine-tuning the gene-regulatory networks controlling dorso-ventral polarity in the developing limb bud. Its loss results in the En1-related dorsal ventral limb phenotype, a subset of the full En1-associated phenotype. Our findings demonstrate that mutations involving lncRNA loci can result in human Mendelian disease. There has been enormous progress in exploring disease variants in the human genome. Yet, the interpretation of variants in the non-coding genome remains a challenge owing to the myriad mechanisms by which they can potentially cause disease. Besides disrupting cis-regulatory elements, non-coding variants may interfere with the function of non-coding transcripts. Indeed, a substantial fraction of the human genome is transcribed into RNA, although most transcripts lack protein-coding potential and are referred to as non-coding transcripts 2. Characterization of a small number of these RNA molecules has revealed that they may have roles as regulators of gene expression through diverse modes of action 3. However, the identification of functional non-coding transcript loci remains challenging. Thus, annotating non-coding transcript loci and unravelling their function will substantially improve our knowledge about gene regulation and the identification and interpretation of non-coding genetic variants with respect to disease pathogenesis. Non-coding deletions cause limb malformations We identified 27-63-kb non-coding deletions of chromosome 2 in three unrelated individuals (patients 1-3) with a type of limb malformation that, to our knowledge, remains undescribed. Affected individuals had a severe shortening and deformation of the legs and feet, 3/4 syndactyly of the hands, as well as the presence of nails on the palmar side of fingers IV and V (Fig. 1a, Extended Data Fig. 1a, b, Supplementary Note 1). Radiographs showed normal femora but severely shortened tibiae, triangular fibulae and malformed or absent bones in the feet (Fig. 1a, Extended Data Fig. 1a, Supplementary Note 1). Exome s...

The aim of this study was to estimate the prevalence of primary headaches in pre-adolescent children, as well as headache frequency and days of treatment in this population. Sample consisted of 1994 children (aged 5-12 years). Parents were interviewed by a paediatric headache specialist using a questionnaire that allowed the classification of headaches using the criteria of the Second Edition of the International Classification of Headache Disorders. The most severe headache type was classified (mutually-exclusive diagnoses). Prevalence and prevalence ratios were calculated overall, as well as by age, gender and race. The overall prevalence of migraine was 3.76%, non-significantly higher in boys (3.9%) than in girls (3.6%). Prevalence of probable migraine was significantly higher than the prevalence of migraine for all ages (overall prevalence of 17.1%). Chronic migraine (CM) happened in 0.8% (girls, 1.15%; boys, 0.5%). Infrequent episodic tension-type headache (ETTH) happened in 2.3% of the sample while prevalence of frequent ETTH was 1.6%. Probable TTH happened in 13.5%. Most children with migraine had consulted a medical doctor because of their headaches, and the proportion was higher among children with CM (93.7%). Prevalence of primary headaches is high in young children. Probable diagnoses are more common than full diagnoses. Consultation rates are elevated.

Migraine and TTH are not comorbid to ADHD overall, but are comorbid to hyperactive-impulsive behavior. Providers and educators should be aware of the association.

High-frequency episodic headaches and chronic daily headaches are common in the preadolescent pediatric population. Health care providers and educators should be aware of the magnitude of the problem to properly identify and treat children with headaches.

No abstract

The influence of prenatal events on the development of headaches at childhood has not been investigated and is the scope of our study. Of 2,173 children identified as the target sample, consents and analyzable data were provided by 1,440 (77%). Parents responded to a standardized questionnaire with a validated headache module and specific questions about prenatal exposures. Odds of chronic daily headache (CDH) were significantly higher when maternal tabagism was reported. When active and passive smoking were reported, odds ratio (OR) of CDH were 2.29 [95% confidence intervals (CI)=1.6 vs. 3.6)]; for active tabagism, OR=4.2 (95% CI=2.1-8.5). Alcohol use more than doubled the chance of CDH (24% vs. 11%, OR=2.3, 95% CI=1.2-4.7). In multivariate analyses, adjustments did not substantially change the smoking/CDH association. Prenatal exposure to tobacco and alcohol are associated with increased rates of CDH onset in preadolescent children. Key words: headache, migraine, childhood, prenatal exposure, tobacco, alcohol.Tabagismo e ingestão alcoólica pré-natal estão associados à cefaleia crônica diária na infância: um estudo de base populacional RESUMO A influência de eventos pré-natais na fisiopatogenia das cefaleias na infância ainda não foi investigada e é o objetivo desse estudo. Da amostra-alvo de 2.173 crianças, um consentimento pós-informado e dados suficientes para as análises foram obtidos de 1.440 (77%). Os pais responderam a um questionário padrão com um módulo de cefaleia validado na população brasileira e questões específicas sobre antecedentes pré-natais. O risco de cefaleia crônica diária (CCD) foi significativamente maior nas crianças cujas mães fumaram durante a gestação. Quando presentes tabagismo ativo e passivo, o risco (OR) de CCD foi de 2,29 [intervalo de confiança (IC) de 95%=1,6-3,6)]; para tabagismo ativo, OR=4,2 (IC 95%=2,1-8,5). O uso de álcool durante a gestação dobrou o risco de CCD (24% vs. 11%, OR=2,3, IC 95%=1,2-4,7). Nas análises multivariadas, os ajustes não modificaram, substancialmente a associação entre tabagismo materno durante a gestação e CCD. A exposição pré-natal ao tabaco e ao álcool encontra-se associada à CCD de início na infância. Palavras-chaves: cefaleia, enxaqueca, migrânea, infância, tabaco, álcool. The epidemiology of frequent headaches in the pre-adolescent pediatric population is poorly known, but limited evidence suggests that headaches on more than 10 days per month happen in over 4% of this population 1 . This relatively high

Frequency of headaches in children is influenced by frequency of headaches in the mother and seems to aggregate in families. Future studies should focus on the determinants of headache aggregation, including genetic and non-genetic factors.

Headache is one of the most common symptoms in children and adolescents, and headache syndromes are an important reason for medical consulting. According to the second edition of the International Classification of Headache Disorders, there are 196 possible headache diagnoses, of which 113 have been described in pediatric population. Herein, we focus on unusual pediatric headache syndromes. We group them as headaches with migraine features, short-duration headaches with autonomic features, short-duration headaches without autonomic features, and potentially ominous forms of headaches. Although rare as single entities, providers focusing on pediatric headaches certainly will face some of these headaches and need to be comfortable on the diagnostic approach.