Microtia is the second most common maxillofacial birth defect in neonates and has an prevalence rate of 3.06/10 000 in China, and 20%-60% of microtia cases is associated with a certain type of syndrome. This article elaborates on the clinical phenotypes and genetic characteristics of three microtia-associated syndromes (MASs) with high prevalence, high incidence rate of ear deformity, and definite genetic etiology, i.e., oculo-auriculo-vertebral spectrum, branchio-oto-renal spectrum disorder, and Treacher-Collins syndrome, and summarizes another three common MASs, so as to provide a reference for the genetic diagnosis of neonatal MAS.
China ; Congenital Microtia/genetics* ; Humans ; Infant, Newborn ; Phenotype ; Prevalence ; Syndrome

OBJECTIVE: To analyze the genetic characteristics of a child with Meier-Gorlin syndrome (MGS) due to a homozygous variant of the ORC6 gene. METHODS: A child who was admitted to the Children's Hospital Affiliated to Soochow University on March 25, 2019 due to growth retardation was selected as the study subject. Clinical data of the child was collected. Whole exome sequencing was carried out for the child. Candidate variant was validated by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a 8-year-and-3-month-old male, has featured short stature, small ears, bilateral cryptorchidism and patellar dysplasia. His parents were of first cousins. The child was found to harbor a homozygous c.712A>T (p.K238*) missense variant of the ORC6 gene, which may lead to premature termination of protein translation. Sanger sequencing confirmed that both of his parents were heterozygous carriers. Based on the guidelines from the American College of Medical Genetics and Genomics, the variant was classified as pathogenic (PVS1_Moderate+PM2_Supporting+PM3+PP3+PP4). CONCLUSION The homozygous c.712A>T (p.K238*) variant probably underlay the MGS in this child.
Humans ; Infant ; Male ; Computational Biology ; Congenital Microtia/genetics* ; Dwarfism/genetics* ; Growth Disorders/genetics* ; Origin Recognition Complex/genetics*

OBJECTIVETo screen for abnormal methylation in CpG islands and CpG sites through whole genome of congenital microtia to identify their associated genes. To discuss the relationship between abnormal methylation level of genes and the etiology of congenital microtia.

METHODSResidual ear cartilage of 50 patients with microtia was collected with ear cartilage of 34 patients without ear malformations as control. Nimblegen CpG promoter array was chosen to screen the 28,226 CpG islands in the whole genome of both experimental and control groups. The genes with differential methylated CpG islands were selected. SpectroCHIP array was chosen to detect the methylation level of each CpG site in abnormal methyletion CpG islands of both experimental and control groups. The CpG sites with differential methylation level were selected.

RESULTSThere were 36 CpG islands with differential methylated level in whole genome between experimental group and control group, among which 29 CpG islands were connected with 29 named genes. In the abnormal methylated CpG islands of COL18A1, MYH14, RBMY1A1 and ZIC3, 6 differentially methylated CpG sites were found with statistical significance. The methylation level of these 6 CpG sites in experimental group and control group were COL18A1_2_CpG_170.9783 +/- 0.0235 and 0.9526 +/- 0.0589; MYH14_CpG_170.9600 +/- 0.0414 and 0.9284 +/- 0.0655; RBMY1A1_1_CpG_3.40.9966 +/- 0.0055 and 0.9914 +/- 0.0069; RBMY1A1_1_CpG_130.9648 +/- 0.0118 and 0.9757 +/- 0.0127; ZIC3_3_CpG_150.0867 +/- 0.0212 and 0.0543 +/- 0.0399; ZIC3_2_CpG_270.3775 +/- 0.1816 and 0.472 3 +/- 0.0439.

CONCLUSIONSThe DNA methylation profile of the entire genome is initially established. The abnormal methylated CpG islands of COL18A1, MYH14, RBMY1A1 and ZIC3 might be related to the pathogenesis of microtia.

Base Sequence ; Cartilage ; Case-Control Studies ; Congenital Microtia ; genetics ; CpG Islands ; genetics ; DNA Methylation ; Humans ; Promoter Regions, Genetic

OBJECTIVETo identify the genetic cause for a 11-year-old Chinese boy with Meier-Gorlin syndrome (MGS).

METHODSChromosomal microarray analysis (CMA) was used to detect potential variations, while whole exome sequencing (WES) was used to identify sequence variants. Sanger sequencing was used to confirm the suspected variants.

RESULTSThe boy has featured short stature, microtia, small patella, slender body build, craniofacial anomalies, and small testes with normal gonadotropin. A complete uniparental disomy of chromosome 16 was revealed by CMA. WES has identified a novel homozygous mutation c.67A>G (p.Lys23Glu) in ORC6 gene mapped to chromosome 16. As predicted by Alamut functional software, the mutation may affect the function of structural domain of the ORC6 protein.

CONCLUSIONThe patient is probably the first diagnosed MGS case in China, who carried a novel homozygous mutation of the ORC6 gene and uniparental disomy of chromosome 16. The effect of this novel mutation on the growth and development needs to be further investigated.

Base Sequence ; Child ; Chromosomes, Human, Pair 16 ; genetics ; Congenital Microtia ; genetics ; Family Health ; Fathers ; Growth Disorders ; genetics ; Heterozygote ; Humans ; Male ; Micrognathism ; genetics ; Mutation ; Origin Recognition Complex ; genetics ; Patella ; abnormalities ; Polymerase Chain Reaction ; methods ; Sequence Analysis, DNA ; methods ; Uniparental Disomy ; genetics