OBJECTIVETo analyze three cases with partial 21q trisomy, and correlate their genotypes with phenotypes.

METHODSG-banding chromosomal analysis and single nucleotide polymorphism (SNP array) were performed for the three cases and their parents.

RESULTSSNP array has detected partial 21q trisomy in three cases and one mother, with variable size and location of the duplications. Case 1 harbored a 12.35 Mb duplication at 21q22.11q22.3, which spanned the Down syndrome critical region. Case 2 harbored a 35.32 Mb duplication at 9p24.3p13.3 and a 14.42 Mb duplication at 21q11.2q21.3, with the former spanning the partial 9p trisomy syndrome critical region excluding the Down syndrome critical region, and was inherited from his mother. Case 3 harbored a 4.17 Mb tetraploidy at 21q11.2q21.1 in the form of mosaicism, which spared the Down syndrome critical region. His mother carried a 4.17 Mb triploidy at 21q11.2q21.1, which was also a mosaicism.

CONCLUSIONPartial 21q trisomy may occur in various forms and its clinical phenotypes are heterogeneous. Combined use of genetic techniques, particularly SNP array, is crucial for diagnosing partial 21q trisomy and delineating its genotype-phenotype correlation.

Child, Preschool ; Chromosome Banding ; Down Syndrome ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Microarray Analysis ; methods ; Polymorphism, Single Nucleotide

OBJECTIVE: To explore the genetic etiology of two pedigrees affected with congenital arthrogryposis. METHODS: Whole exome sequencing (WES) was used to screen potential variations in the proband. Suspected variations were analyzed with bioinformatics software and validated by Sanger sequencing. RESULTS: A heterozygous c.1123G>A (p.Glu375Lys) variation was detected in the proband and an affected fetus from pedigree 1, while a de novo heterozygous c.118 G>A (p.Val40Met) variation was detected in an affected fetus from pedigree 2. CONCLUSION The two heterozygous variations of the MYH3 gene probably underlie the disease in the pedigrees. Above results have facilitated genetic counseling and prenatal diagnosis.
Arthrogryposis ; Cytoskeletal Proteins ; genetics ; Female ; Heterozygote ; Humans ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Whole Exome Sequencing