Research progress of risk factors of Leber’s hereditary optic neuropathy / 中华眼底病杂志

Leber’s hereditary optic neuropathy (LHON) is a paradigm maternal hereditary eye disease, mainly involving the retinal and macular fibers of the optic disc in the anterior ethmoid plate of the sclera. LHON has the characteristics of sex bias among males and incomplete penetrance. Primary mitochondrial DNA mutations m.11778G>A, m. 14484T>C, m.3460G>A are the molecular basis of LHON. However, other risk factors, such as secondary mitochondrial DNA mutations, mitochondrial haplotypes, nuclear modification genes, estrogen, vitamin B12 and environmental factors, work together to affect its phenotypic expression. The clinical diagnosis of LHON mainly limited to the detection of the primary mutation site of mitochondrial DNA. Therefore, comprehensive analysis of multiple risk factors of LHON will facilitate to construct multi-dimensional model of prevention, diagnosis and treatment system, which provide accurate and individualized medical services for patients. These may alleviate the incidence in LHON families. It also provides new ideas and different angles for the in-depth study of the pathogenesis of LHON.

Genetic analysis of a fetus with multiple malformations caused by complex translocations of four chromosomes / 浙江大学学报·医学版

OBJECTIVE@#To conduct genetic analysis in a fetus with complex translocation of four chromosomes.@*METHODS@#G-banded chromosome karyotype analysis, single nucleotide polymorphism array (SNP array) and fluorescence hybridization (FISH) were performed in a fetus with multiple malformations. Peripheral blood chromosome karyotype and FISH were also carried out for the parents.@*RESULTS@#The fetal amniotic fluid karyotype was 46, XY, t(12; 13)(q22; q32). SNP array analysis showed that there were 20 192 kb duplication at 1q42.13q44 and 13 293 kb deletion at 15q26.1q26.3 in the fetus. The results of karyotype and SNP array were inconsistent. FISH analyses on the parental peripheral blood samples demonstrated that the mother was a cryptic 46, XX, t(1; 15)(q42.1; q26.1) translocation. The fetus had inherited 46, XY, t(12; 13)(q22; q32) from his father and der(15)t(1; 15)(q42.1; q26.1) from his mother.@*CONCLUSIONS@#The 1q42.13q44 duplication and 15q26.1q26.3 deletion may have contributed to the abnormal sonographic features of the fetus. The combination of cytogenetic, SNP array and FISH techniques was beneficial for providing an accurate genetic counseling.

Single nucleotide polymorphism microarray in prenatal diagnosis of fetuses with absent nasal bone / 浙江大学学报·医学版

OBJECTIVE@#To assess the clinical application of single nucleotide polymorphism microarray (SNP array) in prenatal genetic diagnosis for fetuses with absent nasal bone.@*METHODS@#Seventy four fetuses with absent nasal bone detected by prenatal ultrasound scanning were recruited from Women's Hospital, Zhejiang University School of Medicine during June 2015 and October 2018. The chromosome karyotypes analysis and SNP array were performed. The correlation between absent fetal nasal bone and chromosome copy number variants was analyzed.@*RESULTS@#Among 74 fetuses, 19 were detected to have chromosomal abnormalities, including 16 cases of trisomy-21, 1 case of trisomy-18 and two cases of micro-deletion/duplication. Among 46 cases with isolated absence of nasal bone, 3 had trisomy-21, and 1 had a micro-duplication. Absence of nasal bone in association with nuchal translucency thickening had a higher rate of abnormal karyotypes compared with isolated absence of nasal bone (=32.27,<0.01).@*CONCLUSIONS@#Fetuses with absent nasal bone and nuchal translucency thickening are likely to have chromosome abnormalities, and SNP array testing is recommended to exclude the chromosome abnormalities.

Application of single nucleotide polymorphism microarray in clinical diagnosis of intellectual disability or retardation / 浙江大学学报·医学版

OBJECTIVE@#To assess the clinical application of single nucleotide polymorphism microarray (SNP array) in patients with intellectual disability/developmental delay(ID/DD).@*METHODS@#SNP array was performed to detect genome-wide DNA copy number variants (CNVs) for 145 patients with ID/DD in Women's Hospital, Zhejiang University School of Medicine from January 2013 to June 2018. The CNVs were analyzed by CHAS software and related databases.@*RESULTS@#Among 145 patients, pathogenic chromosomal abnormalities were detected in 32 cases, including 26 cases of pathogenic CNVs and 6 cases of likely pathogenic CNVs. Meanwhile, 18 cases of uncertain clinical significance and 14 cases of likely benign were identified, no significant abnormalities were found in 81 cases (including benign).@*CONCLUSIONS@#SNP array is effective for detecting chromosomal abnormalities in patients with ID/DD with high efficiency and resolution.