Humans ; Angelman Syndrome/therapy*

OBJECTIVE: To explore the genetic etiology for a Chinese pedigree affected with Angelman syndrome (AS). METHODS: The proband with phenotypes suggestive of AS was subjected to copy number variation sequencing (CNV-seq), methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and high-throughput next generation sequencing (NGS). Variant of the UBE3A gene was verified among family members by Sanger sequencing and bioinformatic analysis. RESULTS: NGS revealed that the proband has carried a heterozygous variant of the UBE3A gene, namely c.1517G>A (p.R506H). The variant has co-segregated with the disease in the pedigree. Multiple amino acid sequence alignment showed that the site of mutant residue is conserved among nine homologous species. The variant was predicted to be deleterious by bioinformatic analysis. CONCLUSION A novel variant of the UBE3A gene has been identified in a Chinese pedigree affected with AS. Above finding has further expanded the spectrum of UBE3A gene variants and phenotypes of AS, which also facilitated molecular diagnosis and genetic counseling for the family.
Angelman Syndrome/genetics* ; China ; DNA Copy Number Variations ; Humans ; Mutation ; Pedigree ; Phenotype

Angelman syndrome (AS) is a distinct condition that presents with severe developmental delay. This condition also presents with speech impairment, ataxia/tremor, and inappropriate laughter. Some other features in most patients include microcephaly, seizures, tongue protrusion, wide mouth, and hypopigmentation. This case aims to emphasize the value of diagnosis in a patient with developmental delay. The diagnosis allows anticipation of the development of other possible problems and guides appropriate management. This report also aims to increase awareness regarding the condition. Here we present a 71-month-old Filipino male with developmental delay at six months, seizures at 10 months with a note of an overall happy demeanor and frequent inappropriate bouts of laughter at one year old. The patient also presented with severe stunting, microcephaly, wide mouth and ataxic gait. Through pattern recognition and the updated consensus of its diagnostic criteria, and confirmation via fluorescence in situ hybridization (FISH), which revealed a deletion in chromosome 15q11, the diagnosis of AS was made. This case re-emphasizes the role of clinical recognition of this condition and its confirmation via cytogenetic techniques like FISH, which will aid appropriate management and counseling for the patient and their families.
Angelman Syndrome

OBJECTIVE: To explore the genetic basis for a fetus featuring growth restriction and validate the effectiveness of a novel noninvasive prenatal testing (NIPT) technique for the detection of chromosomal microdeletions. METHODS: Next-generation sequencing(NGS) and fluorescence in situ hybridization(FISH) were used to analyze the DNA of the fetus. Conventional G-banding was used to analyze the karyotypes of the fetus and its parents. High-throughput sequencing was used to analyze free fetal DNA. RESULTS: NGS analysis has revealed a 4.88 Mb deletion at 15q11.2-q13.1 region in the fetus, which has a 99% overlap with the critical region of Prader-Willi syndrome (Type 2) and Angelman syndrome (Type 2) and encompassed critical genes including SNRPN and UBE3A. NIPT also revealed a 4.6 Mb deletion at 15q12, which was consistent with the results of fetal cord blood and amniotic DNA testing. FISH assay has confirmed the result of NGS. By karyotying, all subjects showed a normal karyotypes at a level of 320~400 bands. CONCLUSION It is quite necessary to carry out genetic testing on fetuses showing growth restriction. NIPT for fetal chromosomal microdeletions/microduplication syndromes is highly accurate for the diagnosis of Prader-Willi/Angelman syndrome.
Angelman Syndrome ; Chromosome Banding ; Chromosomes, Human, Pair 15 ; Female ; Fetus ; Humans ; In Situ Hybridization, Fluorescence ; Prader-Willi Syndrome ; Pregnancy

OBJECTIVE: To provide genetic testing for two brothers with mental retardation and epilepsy. METHODS: Array comparative genomic hybridization (aCGH) was used to detect copy number variations in the two patients, their parents and maternal grandparents. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was utilized to delineate the deleted region in the pedigree. RESULTS: A 138 kb deletion in 15q11.2 region was detected by aCGH in both patients, which encompassed part of the UBE3A gene. MS-MLPA has narrowed down the region to exons 8 to 14 of the UBE3A gene. The same deletion was also found in their mother and grandfather. CONCLUSION The pathogenesis of this rare form of recurrent Angelman syndrome may be attributed to the partial deletion of maternal UBE3A gene.
Angelman Syndrome ; Comparative Genomic Hybridization ; DNA Copy Number Variations ; Female ; Gene Deletion ; Humans ; Male ; Sequence Deletion ; Ubiquitin-Protein Ligases

Quality control for genetic analysis has become more important with a drastic increase in testing volume and clinical demands. The molecular diagnostics division of the Korean Association of Quality Assurance for Clinical Laboratory conducted two trials in 2017 on the basis of molecular diagnostics surveys, involving 53 laboratories. The molecular diagnostics surveys included 37 tests: gene rearrangement tests for leukemia (BCR-ABL1, PML-RARA, AML1-ETO, and TEL-AML1), genetic tests for Janus kinase 2, FMS-like tyrosine kinase 3-internal tandem duplication, FMS-like tyrosine kinase 3-tyrosine kinase domain, nucleophosmin, cancer-associated genes (KRAS, EGFR, KIT, and BRAF), hereditary breast and ovarian cancer genes (BRCA1 and BRCA2), Li-Fraumeni syndrome (TP53), Wilson disease (ATP7B), achondroplasia (FGFR3), hearing loss and deafness (GJB2), Avellino (TGFBI), multiple endocrine neoplasia 2 (RET), Huntington disease, spinocerebellar ataxia, spinal and bulbar muscular atrophy, mitochondrial encephalopathy with lactic acidosis and stroke-like episodes, myoclonic epilepsy ragged red fibre, Leber hereditary optic neuropathy, Prader-raderd Angelman syndrome, Duchenne muscular dystrophy, spinal muscular atrophy, fragile X syndrome, apolipoprotein E genotyping, methylenetetrahydrofolate reductase genotyping, and ABO genotyping. Molecular genetic surveys revealed excellent results for most participants. The external quality assessment program for genetic analysis in 2017 proved useful for continuous education and the evaluation of quality improvement.
Achondroplasia ; Acidosis, Lactic ; Angelman Syndrome ; Apolipoproteins ; Brain Diseases ; Breast ; Deafness ; Education ; Epilepsies, Myoclonic ; Fragile X Syndrome ; Gene Rearrangement ; Hearing Loss ; Hepatolenticular Degeneration ; Huntington Disease ; Janus Kinase 2 ; Korea* ; Laboratory Proficiency Testing ; Leukemia ; Li-Fraumeni Syndrome ; Methylenetetrahydrofolate Reductase (NADPH2) ; Molecular Biology ; Multiple Endocrine Neoplasia ; Muscular Atrophy, Spinal ; Muscular Disorders, Atrophic ; Muscular Dystrophy, Duchenne ; Optic Atrophy, Hereditary, Leber ; Ovarian Neoplasms ; Pathology, Molecular* ; Phosphotransferases ; Quality Control ; Quality Improvement ; Spinocerebellar Ataxias ; Vascular Endothelial Growth Factor Receptor-1

OBJECTIVETo explore the genetic cause for two familial Angelman syndrome cases and correlation between the clinical phenotypes and their genetic basis.

METHODSKaryotyping analysis and microarray assay were carried out to exclude chromosome anomalies and uniparental disomy. The UBE3A gene was analyzed for potential point mutations, deletions, insertions and splice site mutations. Reverse transcription PCR was used to evaluate splicing mutation of the RNA transcripts.

RESULTSDNA sequencing showed the proband of family 1 has carried a novel maternal UBE3A splice acceptor site mutation, resulting in a guanine-to-cytosine transversion (IVS15-1G>C). Reverse transcription PCR revealed the proband and his mother both carried heterozygous mutant transcripts with loss of 54 and 59 nucleotides in exon 16, respectively. The proband displayed severe mental retardation, ataxia, seizures and inappropriate laughter. The siblings of family 2 has carried a novel maternal missense mutation in exon 16 of the UBE3A gene (c.2540C>T). She also presented with mental retardation, absent speech, mild ataxia and inappropriate laughter.

CONCLUSIONThe novel IVS15-1G>C and c.2540 C>T mutations of the UBE3A gene probably underlie the AS in the two families. Compared with small-scale mutations, larger fragments mutations can produce more severe phenotypes.

Angelman Syndrome ; genetics ; Female ; Humans ; Karyotyping ; Male ; Mutation ; Ubiquitin-Protein Ligases ; genetics

OBJECTIVETo analyze a case with Angelman syndrome (AS) using single nucleotide polymorphism array (SNP array) and explore its genotype-phenotype correlation.

METHODSG-banded karyotyping and SNP array were performed on a child featuring congenital malformations, intellectual disability and developmental delay. Mendelian error checking based on the SNP information was used to delineate the parental origin of detected abnormality. Result of the SNP array was validated with fluorescence in situ hybridization (FISH).

RESULTSThe SNP array has detected a 6.053 Mb deletion at 15q11.2q13.1 (22,770,421- 28,823,722) which overlapped with the critical region of AS (type 1). The parents of the child showed no abnormal results for G-banded karyotyping, SNP array and FISH analysis, indicating a de novo origin of the deletion. Mendelian error checking based on the SNP information suggested that the 15q11.2q13.1 deletion was of maternal origin.

CONCLUSIONSNP array can accurately define the size, location and parental origin of chromosomal microdeletions, which may facilitate the diagnosis of AS due to 15q11q13 deletion and better understanding of its genotype-phenotype correlation.

Angelman Syndrome ; genetics ; Child ; Genotype ; Humans ; Karyotyping ; methods ; Male ; Phenotype ; Polymorphism, Single Nucleotide ; genetics

OBJECTIVETo verify the diagnosis of Angelman syndrome(AS) in a proband in order to provide prenatal diagnosis for his family.

METHODSArray comparative genome hybridization(array-CGH) and fluorescence in situ hybridization(FISH) on metaphase chromosomes were performed.

RESULTSThe karyotype of the proband was normal, and a regional deletion of 15q11.1-11.2 was detected by array-CGH. FISH analysis has confirmed loss of heterozygosity in 15q11.2. No positive results were obtained by array-CGH or karyotype analysis. Amniotic fluid sample was taken from the proband's mother upon her subsequent pregnancy. The karyotype of the fetus was normal, but SNP microarray chip analysis has identified loss of heterozygosity in 8p23.1-p22. As no abnormality was observed by ultrasound and other prenatal examinations, the pregnancy was recommended to continue to full-term, and a healthy infant was born.

CONCLUSIONClinically suspected AS can be diagnosed by array-CGH and FISH. The result may facilitate accurate genetic counseling and prenatal diagnosis for the affected family.

Adult ; Angelman Syndrome ; diagnosis ; genetics ; Chromosome Aberrations ; Chromosome Deletion ; Chromosomes, Human, Pair 15 ; genetics ; Chromosomes, Human, Pair 8 ; genetics ; Comparative Genomic Hybridization ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; In Situ Hybridization, Fluorescence ; Infant, Newborn ; Karyotyping ; Loss of Heterozygosity ; Oligonucleotide Array Sequence Analysis ; Polymorphism, Single Nucleotide ; Pregnancy ; Pregnancy Outcome ; Prenatal Diagnosis ; methods

OBJECTIVETo investigate the genotype-phenotype correlation in patients with Angelman syndrome/Prader-Willi syndrome (AS/PWS) and assess the application value of high-resolution single nucleotide polymorphism microarrays (SNP array) for such diseases.

METHODSTwelve AS/PWS patients were diagnosed through SNP array, fluorescence in situ hybridization (FISH) and karyotype analysis. Clinical characteristics were analyzed.

RESULTSDeletions ranging from 4.8 Mb to 7.0 Mb on chromosome 15q11.2-13 were detected in 11 patients. Uniparental disomy (UPD) was detected in only 1 patient. Patients with deletions could be divided into 2 groups, including 7 cases with class I and 4 with class II. The two groups however had no significant phenotypic difference. The UPD patient had relatively better development and language ability. Deletions of 6 patients were confirmed by FISH to be of de novo in origin. The risk to their sibs was determined to be less than 1%.

CONCLUSIONThe phenotypic differences between AS/PWS patients with class I and class II deletion need to be further studied. SNP array is useful in detecting and distinguishing of patients with deletion or UPD. This method may be applied for studying the genotype-phenotype association and the mechanism underlying AS/PWS.

Angelman Syndrome ; diagnosis ; genetics ; Child, Preschool ; Chromosome Deletion ; Female ; Genotype ; Humans ; Infant ; Karyotyping ; Male ; Phenotype ; Polymorphism, Single Nucleotide ; Prader-Willi Syndrome ; diagnosis ; genetics