Intragenic multi-exon deletion in the FBN1 gene in a child with mildly dilated aortic sinus: a retrotransposal event.

Marfan syndrome is an autosomal dominant disorder affecting mainly the skeletal, ocular and cardiovascular systems. Most cases are caused by mutations in the fibrillin-1 gene (FBN1), although there are some reports on deletions involving FBN1 and other additional genes. We report a male patient who was first evaluated at 4 years of age. Echocardiogram showed a mildly dilated aortic sinus. He also had a history of muscular ventral septal defect which was closed spontaneously and trivial mitral regurgitation. Other phenotypic features include frontal bossing, anteverted ears, joint hyperlaxity, learning disability, skin striae, and height and weight in the >97th centile but no other diagnostic findings of MFS and does not fulfill the revised Ghent criteria. Chromosomal microarray analysis showed a deletion of approximately 36.8 kb at 15q21.1, which starts in intron 6 and ends in intron 9 and includes three FBN1 exons. Sequence analysis of the breakpoint region confirmed the deletion and revealed a concomitant insertion of a retrotransposon within the intron 6/intron 9 region. The intragenic deletion of exons 7-9 was likely the result of a retrotransposition event by a MAST2-SVA element mediated by repetitive sequences.

A Novel Interferon Regulatory Factor 6 Mutation in an Asian Family With Van der Woude Syndrome.

Van der Woude syndrome (VWS) is a rare autosomal dominant genetic disorder characterized by orofacial clefting and lip pits. Mutations in the transcription factor interferon regulatory factor 6 gene (IRF6) have been identified in individuals with VWS. We performed direct sequencing of the gene for molecular investigation of a proband with Bangladeshi-Malay ancestry. A novel transition mutation (c.113T>C), which resulted in an amino acid substitution (p.Ile38Thr) in the deoxyribonucleic acid-binding domain was detected. Testing of family members showed that the mutation segregated with the VWS phenotype for members of her immediate family. Although there is some phenotypic variability, all of the affected members are of the female gender.

Next-generation sequencing using a pre-designed gene panel for the molecular diagnosis of congenital disorders in pediatric patients.

BACKGROUND: Next-generation sequencing (NGS) has revolutionized genetic research and offers enormous potential for clinical application. Sequencing the exome has the advantage of casting the net wide for all known coding regions while targeted gene panel sequencing provides enhanced sequencing depths and can be designed to avoid incidental findings in adult-onset conditions. A HaloPlex panel consisting of 180 genes within commonly altered chromosomal regions is available for use on both the Ion Personal Genome Machine (PGM) and MiSeq platforms to screen for causative mutations in these genes. METHODS: We used this Haloplex ICCG panel for targeted sequencing of 15 patients with clinical presentations indicative of an abnormality in one of the 180 genes. Sequencing runs were done using the Ion 318 Chips on the Ion Torrent PGM. Variants were filtered for known polymorphisms and analysis was done to identify possible disease-causing variants before validation by Sanger sequencing. When possible, segregation of variants with phenotype in family members was performed to ascertain the pathogenicity of the variant. RESULTS: More than 97% of the target bases were covered at >20×. There was an average of 9.6 novel variants per patient. Pathogenic mutations were identified in five genes for six patients, with two novel variants. There were another five likely pathogenic variants, some of which were unreported novel variants. CONCLUSIONS: In a cohort of 15 patients, we were able to identify a likely genetic etiology in six patients (40%). Another five patients had candidate variants for which further evaluation and segregation analysis are ongoing. Our results indicate that the HaloPlex ICCG panel is useful as a rapid, high-throughput and cost-effective screening tool for 170 of the 180 genes. There is low coverage for some regions in several genes which might have to be supplemented by Sanger sequencing. However, comparing the cost, ease of analysis, and shorter turnaround time, it is a good alternative to exome sequencing for patients whose features are suggestive of a genetic etiology involving one of the genes in the panel.

Influence of mu-opioid receptor variant on morphine use and self-rated pain following abdominal hysterectomy.

UNLABELLED: A common variant in the mu-opioid receptor gene (OPRM1) has been associated with response to opioid analgesia. Our previous data revealed significantly higher amounts of morphine self-administered by patients carrying the 118G allele compared to those with the 118A allele after elective cesarean section. In this study, the association of this genetic variation with pressure pain, postoperative pain scores, and amount of morphine used was investigated in 973 patients undergoing scheduled total hysterectomy under general anesthesia. Preoperative pressure pain threshold and tolerance were also measured for most patients. For pressure pain, OPRM1 genotype was not significantly associated with either pain threshold or pain tolerance. Statistically significant associations were found for postoperative pain and the total amount of morphine used, with the GG group reporting higher pain scores and using the most morphine. When analysis was stratified by ethnic group, differences in weight-adjusted morphine for the 3 genotypic groups were also significant for the Chinese and Asian Indians. These results extend our previous finding on the association of higher self-reported pain and morphine use for acute postoperative pain with OPRM1 118G to patients who had total hysterectomy under general anesthesia. PERSPECTIVE: In a large cohort of patients undergoing hysterectomy, we found large variability in the self-rated pain scores and the amount of morphine required for pain relief. Both are associated with OPRM1 genotypes and preoperative experimental pressure pain threshold. Experimental pressure pain tolerance is also associated with postoperative pain.

De novo trisomy 12p in twin girls with different levels of mosaicism.

We report on a pair of twins with trisomy 12p diagnosed postnatally. The girls were referred for dysmorphism and global developmental delay and have been followed from 10 months of age. They have different levels of mosaicism for both buccal cells and lymphocytes. Although their phenotypic features were similar, there were different degrees of severity which correlate with the different levels of mosaicism.

De novo 3q22.1 q24 deletion associated with multiple congenital anomalies, growth retardation and intellectual disability.

We describe a boy with a de novo deletion of 15.67 Mb spanning 3q22.1q24. He has bilateral micropthalmia, ptosis, cleft palate, global developmental delay and brain, skeletal and cardiac abnormalities. In addition, he has bilateral inguinal hernia and his right kidney is absent. We compare his phenotype with seven other patients with overlapping and molecularly defined interstitial 3q deletions. This patient has some phenotypic features that are not shared by the other patients. More cases with smaller deletions defined by high resolution aCGH will enable better genotype-phenotype correlations and prioritizing of candidate genes for the identification of pathways and disease mechanisms.

A submicroscopic deletion involving part of the CREBBP gene detected by array-CGH in a patient with Rubinstein-Taybi syndrome.

We report a girl with Rubinstein-Taybi syndrome (RSTS) who was found to have copy number loss on 16p13.3 by array-CGH. She has developmental delay and other features of RSTS including downslanting palpebral fissures, a prominent nose with the nasal septum extending below the alae nasi, broad thumbs and big toes, postaxial polydactyly of the right foot and constipation from birth. We report the junction sequence across the breakpoint region for a microdeletion in RSTS. The sequencing results also showed that the deletion was 81.4kb involving three genes DNASE 1, TRAP 1, and CREBBP.

Ethnicity and OPRM variant independently predict pain perception and patient-controlled analgesia usage for post-operative pain.

BACKGROUND: Morphine consumption can vary widely between individuals even for identical surgical procedures. As mu-opioid receptor (OPRM1) is known to modulate pain perception and mediate the analgesic effects of opioid compounds in the central nervous system, we examined the influence of two OPRM polymorphisms on acute post-operative pain and morphine usage in women undergoing elective caesarean delivery. RESULTS: Data on self-reported pain scores and amount of total morphine use according to patient-controlled analgesia were collected from 994 women from the three main ethnic groups in Singapore. We found statistically significant association of the OPRM 118A>G with self-administered morphine during the first 24-hour postoperative period both in terms of total morphine (p = 1.7 x 10(-5)) and weight-adjusted morphine (p = 6.6 x 10(-5)). There was also significant association of this OPRM variant and time-averaged self-rated pain scores (p = 0.024). OPRM 118G homozygotes used more morphine and reported higher pain scores than 118A carriers. Other factors which influenced pain score and morphine usage include ethnicity, age and paying class. CONCLUSION: Our results suggest that ethnicity and OPRM 118A>G genotype are independent and significant contributors to variation in pain perception and postoperative morphine use in patients undergoing cesarean delivery.

A118G single nucleotide polymorphism of human mu-opioid receptor gene influences pain perception and patient-controlled intravenous morphine consumption after intrathecal morphine for postcesarean analgesia.

BACKGROUND: Previous studies have shown that genetic variability at position 118 of the human mu-opioid receptor gene altered patients' response to intravenous morphine. The purpose of this study was to investigate whether this polymorphism contributes to the variability in response to morphine for postcesarean analgesia. METHODS: After investigators obtained informed consent, 588 healthy women received 0.1 mg intrathecal morphine for postcesarean analgesia. Their blood samples were genotyped for the A118G polymorphism-A118 homozygous (AA), heterozygous (AG), or homozygous for the G allele (GG). Pain scores, the severity of nausea and vomiting, the incidence of pruritus, and the total self-administered intravenous morphine were recorded for the first 24 postoperative hours. RESULTS: Two hundred seventy women (46%) were AA, 234 (40%) were AG, and 82 (14%) were GG. The 24-h self-administered intravenous morphine consumption was lowest in the AA group (P = 0.001; mean, 5.9; 95% confidence interval, 5.1-6.8) versus the AG (8.0; 6.9-9.1) and GG groups (9.4; 7.3-11.5). Pain scores were lowest in the AA group and highest in the GG group, with a statistically significant difference detected between AA, AG, and GG (P = 0.049). Total morphine consumption was also influenced by patients' age and paying status. AA group was associated with the highest incidence of nausea (26 of 272 [9.6%]; P = 0.02) versus the other two groups (13 of 234 [5.6%] and 1 of 82 [1.2%] for AG and GG, respectively). CONCLUSION: Genetic variation at position 118 of the mu-opioid receptor is associated with interindividual differences in pain scores, self-administered intravenous morphine, and the incidence of nausea postoperatively.