Female ; Humans ; Mosaicism ; Pregnancy ; Prenatal Care ; Prenatal Diagnosis ; Trisomy/genetics*

Karyotypes were prepared from peripheral blood leukocytes in 18 couples with his-tories of habitual abortions. The Standard chromosome analysis and G-banding techniques were studied. The abnormal karyotypes seen were one case with 20% of 45, XX, -14, -15, t(14/15), one case of 46, XY/45, XY, -21 mosaicism, one case of 45, XX, -14, -21, t(14/21), one case of 46, XX/45, XO mosaicism and one case of 46, XYq+. Many other types of chromosomal abnormalities from many reports in couples with spontaneous abortions are discussed.
Abortion, Habitual/genetics* ; Adult ; Chromosome Aberrations* ; Female ; Human ; Leukocytes/ultrastructure ; Male ; Mosaicism ; Pregnancy ; Translocation (Genetics)

OBJECTIVE: To explore the genetic etiology of a child with Pitt-Hopkins syndrome. METHODS: A child who had presented at the Medical Genetics Center of Gansu Provincial Maternal and Child Health Care Hospital on February 24, 2021 and his parents were selected as the study subjects. Clinical data of the child was collected. Genomic DNA was extracted from peripheral blood samples of the child and his parents and subjected to trio-whole exome sequencing (trio-WES). Candidate variant was verified by Sanger sequencing. Karyotype analysis was also carried out for the child, and her mother was subjected to ultra-deep sequencing and prenatal diagnosis upon her subsequent pregnancy. RESULTS: The clinical manifestations of the proband included facial dysmorphism, Simian crease, and mental retardation. Genetic testing revealed that he has carried a heterozygous c.1762C>T (p.Arg588Cys) variant of the TCF4 gene, for which both parents had a wild-type. The variant was unreported previously and was rated as likely pathogenic based on the guidelines of the American College of Medical Genetics and Genomics (ACMG). Ultra-deep sequencing indicated that the variant has a proportion of 2.63% in the mother, suggesting the presence of low percentage mosaicism. Prenatal diagnosis of amniotic fluid sample suggested that the fetus did not carry the same variant. CONCLUSION The heterozygous c.1762C>T variant of the TCF4 gene probably underlay the disease in this child and has derived from the low percentage mosaicism in his mother.
Child ; Female ; Humans ; Male ; Pregnancy ; Intellectual Disability/genetics* ; Mosaicism ; Mothers ; Mutation ; Parents ; Transcription Factor 4/genetics*

Congenital diaphragmatic hernia (CDH) is often associated with major anomalies and chromosomal abnormalities. Chromosomal abnormalities are usually detected in 9.5% to 34% of fetuses with CDH prenatally diagnosed and the defect has also been reported in association with multiple syndromes such as Pallister-Killian syndrome, Fryns syndrome, Di George syndrome and Apert syndrome. Among the chromosomal abnormalities associated with CDH, trisomy 21, 18, and 13 are most common. Association with complex chromosomal aberrations such as mosaicism has also been reported. However, CDH presented in a fetus with Y-autosome translocation is extremely rare. Herein, we reported a case of fetus with 46,XY/46,X,-Y, +der(Y)t(Y;1)(q12;q12) mosaicism who presented with CDH diagnosed by ultrasonography at 19 weeks' gestation.
*Chromosome Aberrations ; Hernia, Diaphragmatic/*congenital/*diagnosis/genetics ; Humans ; Mosaicism/*embryology ; Prenatal Diagnosis/*methods

OBJECTIVETo detect NF1 gene mutation in a patient with neurofibromatosis type 1.

METHODSFive fragments encompassing the entire coding sequence of the NF1 gene were amplified with reverse transcription PCR. PCR products were directly sequenced. Suspected mutations were verified by sequencing of DNA amplified by PCR using genomic DNA as template. Corresponding exon of family members was also sequenced. Furthermore, the PCR products were inserted into a pGEM-T cloning vector to quantify cells carrying the mutation in different samples derived from the three embryonic layers.

RESULTSThe proband's clinical manifestation was consistent with neurofibromatosis type 1. Sequence analysis has identified a novel heterozygous mutation c.7911 C to T (p.Q2510X) in exon 51 of the NF1 gene in the proband. The same mutation was also detected in peripheral blood cells, uroepithelial cells and oral mucosal cells of the proband, though the signals of uroepithelial cells were significantly weaker. By T cloning-sequencing, recombinants carrying the NF1 gene mutation respectively accounted for 42%, 36% and 12% of all peripheral blood cells, oral mucosal cells and uroepithelial cells .

CONCLUSIONIt is likely that a mutation of NF1 gene has occurred in early embryogenesis of the proband, which in turn has led to generalized mosaicism of neurofibromatosis type 1.

OBJECTIVE: To explore the genetic characteristics of a child with mosaicism Turner syndrome. METHODS: A child who had presented at Linyi People's Hospital on May 19, 2022 due to short stature was selected as the study subject. The child was subjected to combined chromosomal karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray analysis (CMA). RESULTS: The child was found to have a 46,X,i(X)(q10)[94]/45,X[6] karyotype. The result of FISH was nucish(XYpter,XYqter)1[78]/(XYpter)1,(XYqter)3[122]. CMA result for her peripheral blood sample was arr[hg19]Xp22.33p11.1(168551_58526888)×1, and that for her oral mucosal cells was arr[hg19]Xp22.33p11.1(168551_58526888)1-2,Xq11.2q28(63000001_155233098)×2-3. By integrating the above findings, her molecular karyotype was determined as mos 46,X,i(X)(q10)[94]/45,X[6].arr[hg19]Xp22.33p11.1(168551_58526888)×1-2,Xq11.2q28(63000001_155233098)×2-3.nucish(XYpter)1,(XYqter)3[122]/(XYpter,XYqter)1[78], which has indicated mosaicism Turner syndrome. CONCLUSION The 46,X,i(X)(q10)/45,X mosaicism probably underlay the pathogenesis in this child.
Humans ; Child ; Female ; Turner Syndrome/genetics* ; Mosaicism ; In Situ Hybridization, Fluorescence ; Karyotyping ; Karyotype

OBJECTIVE: To report on a family which has two siblings with SCN2A mutation caused by germline mosaicism suffering from autism spectrum disorder/development delay (ASD/DD). METHODS: Clinical data was collected for the proband and his parents. Next generation sequencing (NGS) was carried out on the proband and his parents. Suspected mutations were verified by Sanger sequencing of the proband, his parents and brother. To detect whether there is a low proportion of somatic mosaicism in the parents, a droplet digital PCR was conducted. The result of ddPCR showed that the father was germline mosaicism (0.233%). RESULTS: NGS has identified a de novo splicing mutation of the SCN2A gene, c.605+1G>A, in the proband and his brother. Combined with its clinical phenotype and inheritance pattern, SCN2A was judged to be the pathogenic gene. Above findings strongly suggested parental germline mosaicism. CONCLUSION ASD/DD in siblings with SCN2A mutations caused by germline mosaicism. Paternal mosaicism should be considered as one of the important inheritance patterns for counseling parents with a child carrying SCN2A mutation. The ddPCR can help to reveal very low proportion of germline mosaicism.
Autism Spectrum Disorder ; Germ Cells ; Humans ; Male ; Mosaicism ; Mutation ; NAV1.2 Voltage-Gated Sodium Channel/genetics* ; Siblings

OBJECTIVE: To carry out genetic analysis and parental tracing for a fetus with an inconclusive chromosomal karyotype. METHODS: The fetus and its parents were subjected to combined chromosomal karyotyping, chromosomal microarray analysis (CMA), fluorescence in situ hybridization (FISH) and multiplex PCR testing for Y chromosome microdeletions. RESULTS: The fetus was found to have a karyotype of 45,X[18]/46,X,+mar[72]. CMA revealed that the fetus has carried a 2.6 Mb duplication at Yp11.32p11.31 and a 44.5 Mb deletion at Yq11.21q12. Interphase FISH of amniocytes confirmed the chromosomal mosaicism in the fetus, which has derived from Y chromosome. Multiplex PCR revealed deletion of AZFb and AZFc regions on the Y chromosome. No karyotypic abnormality was found with either parent at 400-band level. CONCLUSION Combined genetic analysis has delineated the aberrant karyotype in the fetus, which has facilitated prediction of its clinical phenotype and genetic counseling.
Chromosomes, Human, Y/genetics* ; Female ; Fetus ; Humans ; In Situ Hybridization, Fluorescence ; Karyotype ; Mosaicism ; Pregnancy ; Prenatal Diagnosis

OBJECTIVE: To carry out genetic testing for a patient with 45,X/46,XY mosaicism and autism spectrum disorder (ASD). METHODS: Peripheral blood samples of the patient and his parents were collected for the extraction of genomic DNA. Trio-based whole exome sequencing and Sanger sequencing were carried out thereafter. RESULTS: The proband and his father were found to harbor a heterozygous c.4781G>A (p.Arg1594Gln) variant of the CACNA1I gene. In addition, the proband was also found to harbor a de novo c.268C>T (p.Arg90Trp) missense variant of the MTRR gene. Based on guidelines of the American College of Medical Genetics and Genomics (ACMG), the c.4781G>A (p.Arg1594Gln) variant of the CACNA1I gene was predicted to be pathogenic (PVS1, PM1, PM2, PP3), while the c.268C>T (p.Arg90Trp) variant of the MTRR gene was predicted to be of uncertain significance. CONCLUSION Variants of the CACNA1I and MTRR genes, together with the chromosomal mosaicism, may have predisposed to the susceptibility to the ASD in this patient.
Autism Spectrum Disorder/genetics* ; Genomics ; Heterozygote ; Humans ; Mosaicism ; Whole Exome Sequencing

OBJECTIVE: To explore the clinical phenotype, genetic variant, treatment and prognosis of a child with mosaic variegated aneuploidy syndrome (MVAS). METHODS: Immunological marker screening, chromosomal karyotyping and whole exome sequencing were carried out. RESULTS: The 1-year-11-month old girl has featured severe growth retardation, feeding difficulty, short stature, microcephaly, facial anomalies, scoliosis, visual impairment, hypotonia, chylothorax, and renal lesions. Karyotype analysis of peripheral blood lymphocytes has discovered variegated aneuploidy cells (6/11). DNA sequencing has identified compound heterozygous c.826delG (p.Asp276Metfs*21) and c.2441G>A (p.Arg814His) variants in the BUB1B gene, which were inherited from her father and mother, respectively. CONCLUSION The compound heterozygous variants of the BUB1B gene probably underlie the pathogenesis in this patient.
Aneuploidy ; Chromosome Disorders ; diagnosis ; genetics ; DNA Mutational Analysis ; Female ; Genetic Testing ; Humans ; Infant ; Mosaicism