Osteopoikilosis and multiple exostoses caused by novel mutations in LEMD3 and EXT1 genes respectively - coincidence within one family

<p>Abstract</p> <p>Background</p> <p>Osteopoikilosis is a rare autosomal dominant genetic disorder, characterised by the occurrence of the hyperostotic spots preferentially localized in the epiphyses and metaphyses of the long bones, and in the carpal and tarsal bones <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. Heterozygous <it>LEMD3 </it>gene mutations were shown to be the primary cause of the disease <abbrgrp><abbr bid="B2">2</abbr></abbrgrp>. Association of the primarily asymptomatic osteopokilosis with connective tissue nevi of the skin is categorized as Buschke-Ollendorff syndrome (BOS) <abbrgrp><abbr bid="B3">3</abbr></abbrgrp>. Additionally, osteopoikilosis can coincide with melorheostosis (MRO), a more severe bone disease characterised by the ectopic bone formation on the periosteal and endosteal surface of the long bones <abbrgrp><abbr bid="B4">4</abbr><abbr bid="B5">5</abbr><abbr bid="B6">6</abbr></abbrgrp>. However, not all MRO affected individuals carry germ-line <it>LEMD3 </it>mutations <abbrgrp><abbr bid="B7">7</abbr></abbrgrp>. Thus, the genetic cause of MRO remains unknown. Here we describe a familial case of osteopoikilosis in which a novel heterozygous <it>LEMD3 </it>mutation coincides with a novel mutation in <it>EXT1</it>, a gene involved in aetiology of multiple exostosis syndrome. The patients affected with both <it>LEMD3 </it>and <it>EXT1 </it>gene mutations displayed typical features of the osteopoikilosis. There were no additional skeletal manifestations detected however, various non-skeletal pathologies coincided in this group.</p> <p>Methods</p> <p>We investigated <it>LEMD3 </it>and <it>EXT1 </it>in the three-generation family from Poland, with 5 patients affected with osteopoikilosis and one child affected with multiple exostoses.</p> <p>Results</p> <p>We found a novel c.2203C > T (p.R735X) mutation in exon 9 of <it>LEMD3</it>, resulting in a premature stop codon at amino acid position 735. The mutation co-segregates with the osteopoikilosis phenotype and was not found in 200 ethnically matched controls. Another new substitution G > A was found in <it>EXT1 </it>gene at position 1732 (cDNA) in Exon 9 (p.A578T) in three out of five osteopoikilosis affected family members. Evolutionary conservation of the affected amino acid suggested possible functional relevance, however no additional skeletal manifestations were observed other then those specific for osteopoikilosis. Finally in one member of the family we found a splice site mutation in the <it>EXT1 </it>gene intron 5 (IVS5-2 A > G) resulting in the deletion of 9 bp of cDNA encoding three evolutionarily conserved amino acid residues. This child patient suffered from a severe form of exostoses, thus a causal relationship can be postulated.</p> <p>Conclusions</p> <p>We identified a new mutation in <it>LEMD3 </it>gene, accounting for the familial case of osteopoikilosis. In the same family we identified two novel <it>EXT1 </it>gene mutations. One of them A598T co-incided with the <it>LEMD3 </it>mutation. Co-incidence of <it>LEMD3 </it>and <it>EXT1 </it>gene mutations was not associated with a more severe skeletal phenotype in those patients.</p

Self-Reported Time in Bed and Sleep Quality in Association with Internalizing and Externalizing Symptoms in School-Age Youth

This study investigated the relationship between self-reported time in bed and sleep quality in association with self-reported internalizing and externalizing symptoms in a sample of 285 elementary school students (52% female) recruited from a rural Midwestern elementary school. Path models were used to estimate proposed associations, controlling for grade level and gender. Curvilinear associations were found between time in bed and anxiety, depressive symptoms, and irritability. Marginal curvilinear trends were found between time in bed and emotion dysregulation, reactive aggression, and proactive aggression. Sleep quality was negatively associated with anxiety, depressive symptoms, irritability, reactive aggression, and delinquency engagement. Gender and grade differences were found across models. Findings suggest that examining self-reported time in bed (both linear and quadratic) and sleep quality is important for understanding internalizing and externalizing symptoms associated with sleep in school-age youth. Incorporating self-reported sleep assessments into clinical practice and school-based evaluations may have implications for a child’s adjustment