Disorders of sex development (DSD) are characterized by atypical development of chromosomal, gonadal, or phenotypic sex. 45X,46XY mosaicism is a type of sex chromosome DSD which presents with a wide heterogeneity of manifestations. We report the case of a 13-year-old phenotypically female who presented with clitoromegaly at puberty. Testosterone level was elevated on serology. Out of the 50 cells examined, 43 cells had Monosomy X while 7 cells had a normal male karyotype. She was managed by a multidisciplinary team. Due to the presence of Y chromosome, the solid nodular structure seen on the right gonad in magnetic resonance imaging and the pain caused by the phallus, Laparoscopic bilateral gonadectomy, salpingectomy and clitoroplasty were done after a shared decision making. Histopathology revealed Gonadoblastoma and Germ cell neoplasia-in-situ of the right gonad justifying timely removal. She was then maintained on estrogen for induction of secondary sexual characteristics.

Proteus syndrome (PS) is a mosaic disorder characterized by asymmetric overgrowth of a variety of tissues. Diagnostic criteria established in 1999 emphasized the mosaic distribution of lesions, progressive course, and disproportionate overgrowth. We present a case of proteus syndrome in a 12-year-old Filipino male with 9 year-history of enlargement of the left foot with soft, non-tender mass on the sole with a brain-like surface. Skin punch biopsy of the mass showed cerebriform connective tissue nevi which is pathognomonic of PS.

PS is a very rare disease with prevalence of less than 1 in 1,000,000 live births. Management of PS is extremely challenging, owing to the combination of the individuality of each case, the severity of the disease, and the risks of complications from procedures. A multidisciplinary clinical approach is strongly recommended to obtain the best possible management plans for individual patients.

Disorders of sexual development (DSD) defined as congenital conditions associated with atypical development of anatomical, gonadal or chromosomal sex, is a rare condition that may present with ambiguous genitalia. Included in the varied classes of DSD is mixed gonadal dysgenesis which is known to be due to mosaicism, a chromosomal aberration. Mosaic individuals may have concerns on growth, hormone balance, gonadal development, sex of rearing and fertility. This case report presents an 18-year old student who presented with primary amenorrhea, delayed secondary sexual characteristics and phenotypic features of Turner syndrome who, on chromosomal analysis revealed 45X0/46XY mosaicism. The patient underwent operative laparoscopy with bilateral gonadectomy on the basis of the increased risk of development of gonadal malignancy in phenotypic females with Y-chromosome material. Histopathological analysis revealed bilateral streak gonads. Hormone replacement therapy was then initiated for the induction of secondary female sex characteristics, as treatment for estrogen deficiency, for the induction of pubertal growth spurt and for optimization of bone mineral accumulation. Management of disorders of sexual development is challenging, thus the need for a multidisciplinary approach involving experts in endocrinology, gynecology, psychology and genetics.
GONADAL DYSGENESIS, MIXED ; MOSAICISM ; TURNER SYNDROME ; CASTRATION

Mosaic chromosomal alteration (mCA) is referred to as large-scale somatic mutations on chromosomes, which results in diverse karyotypes in body. The mCA is regarded as one of the phenotypes of aging. Studies have revealed its associations with many chronic diseases such as hematopoietic cancers and cardiovascular diseases, but its genetic basis (e.g. genetic susceptibility variants) is still under-investigated. This paper reviews GWAS studies for mCA on autosomal chromosomes and sex chromosomes [mosaic loss of the Y chromosome (mLOY) and mosaic loss of the X chromosome (mLOX)] based on large population, respectively. Most of the genetic susceptibility loci found in studies for autosomal mCA were associated with copy-neutral loss of heterozygosity. The study of sex chromosome mCA focused on mosaic loss mutations. The number of genetic susceptibility loci for mLOY was high (up to 156), but it was relatively less for mLOX.
Humans ; Male ; Genome-Wide Association Study/methods* ; Mosaicism ; Genetic Predisposition to Disease ; Chromosomes, Human, Y ; Mutation

Pregnancy ; Female ; Humans ; Mosaicism ; Prenatal Diagnosis ; Prenatal Care ; Aneuploidy

OBJECTIVE: To explore the coincidence rate of G-banding karyotype analysis and fluorescence in situ hybridization (FISH) for the diagnosis of children with sex chromosome mosaicisms. METHODS: A retrospective analysis was carried out for 157 children with suspected sex chromosome abnormalities who had presented at Shenzhen Children's Hospital from April 2021 to May 2022. Interphase sex chromosome FISH and G-banding karyotyping results were collected. The coincidence rate of the two methods in children with sex chromosome mosaicisms was compared. RESULTS: The detection rates of G-banding karyotype analysis and FISH were 26.1% (41/157) and 22.9% (36/157) , respectively (P > 0.05). The results of G-banding karyotype analysis showed that 141 cases (89.8%) were in the sex chromosome homogeneity group, of which only 5 cases (3.5%) were inconsistent with the results of FISH. There were 16 cases (10.2%) in the sex chromosome mosaicism group, of which 11 cases (68.8%) were inconsistent with the results of FISH. There was a statistical difference between the two groups in the coincidence rate of the results of the two methods (P < 0.05). CONCLUSION No significant difference was found between G-banding karyotype analysis and FISH in the detection rate of chromosome abnormalities. The coincidence rate in the mosaicism group was lower than that in the homogeneity group, and the difference was statistically significant. The two methods should be combined for clinical diagnosis.
Humans ; Mosaicism ; In Situ Hybridization, Fluorescence/methods* ; Retrospective Studies ; Karyotyping ; Chromosome Aberrations ; Sex Chromosome Aberrations ; Karyotype ; Chromosome Banding ; Sex Chromosomes

OBJECTIVE: To explore the genetic basis, clinical phenotype and pathogenesis for a child with mosaicism ring chromosome 4. METHODS: Clinical data of the child was collected. Peripheral blood chromosomal karyotype G banding analysis, chromosomal microarray analysis (CMA), fluorescence in situ hybridization (FISH) were carried out for the child, in addition with a review of the literature. RESULTS: The child was born full-term with low birth weight, facial dysmorphism, patent ductus arteriosus and ventricular septal defect. His karyotype was determined as mos46,XY,r(4)(p16.3q35.2)[259]/45,XY,-4[25]/47,XY,r(4)(p16.3q35.2), +r(4)(p16.3q35.2)[8]/46,XY,der(4)del(4)(p16.3)inv(4)(p16.3q31.1)[6]/46,XY,dic?r(4;4)(p16.3q35.2;p16.3q35.2)[4]/48,XY,r(4)(p16.3q35.2),+r(4)(p16.3q35.2)×2[3]/46,XY,r(4)(p1?q2?)[2]; CMA result was arr[GRCH37]4p16.3(68 345-2 981 614)×1; FISH result was 45,XY,-4[12]/45,XY,-4×2,+mar1.ish r1(4)(WHS-,D4Z1+)[1]/ 46,XY,-4,+mar1.ishr1(4)(WHS-,D4Z1+)[73]/46,XY,-4,+mar2.ishr2(4)(WHS-,D4Z1++)[1]/47,XY,-4,+mar1×2.ishr1(4) (WHS-, D4Z1+)×2[4]/46,XY,del(4)(p16.3).ish del(4)(p16.3)(WHS-,D4Z1+)[9]. CONCLUSION In this case, the ring chromosome 4 as a de novo variant has produced a number of cell lines during embryonic development and given rise to mosaicism. The clinical phenotype of ring chromosome 4 is variable. The instability of the ring chromosome itself, presence of mosaicism, chromosome breakpoint and range of deletion and/or duplication may all affect the ultimate phenotype.
Humans ; Pregnancy ; Female ; Ring Chromosomes ; In Situ Hybridization, Fluorescence ; Karyotyping ; Karyotype ; Mosaicism

OBJECTIVE: To explore the genetic basis for 7 families with gonadal mosaicism for Duchenne muscular dystrophy (DMD). METHODS: For the 7 families presented at the CITIC Xiangya Reproductive and Genetic Hospital from September 2014 to March 2022, clinical data were collected. Preimplantation genetic testing for monogenic disorders (PGT-M) was carried out for the mother of the proband from family 6. Peripheral venous blood samples of the probands, their mothers and other patients from the families, amniotic fluid samples from families 1 ~ 4 and biopsied cells of embryos cultured in vitro from family 6 were collected for the extraction of genomic DNA. Multiplex ligation-dependent probe amplification (MLPA) was carried out for the DMD gene, and short tandem repeat (STR)/single nucleotide polymorphism (SNP)-based haplotypes were constructed for the probands, other patients, fetuses and embryos. RESULTS: The results of MLPA showed that the probands and the fetuses/probands' brothers in families 1 ~ 4, 5, 7 had carried the same DMD gene variants, whilst the probands' mothers were all normal. The proband in family 6 carried the same DMD gene variant with only 1 embryo (9 in total) cultured in vitro, and the DMD gene of the proband's mother and the fetus obtained through the PGT-M were normal. STR-based haplotype analysis showed that the probands and the fetuses/probands' brothers in families 1 ~ 3 and 5 have inherited the same maternal X chromosome. SNP-based haplotype analysis showed that the proband from family 6 has inherited the same maternal X chromosome with only 1 embryo (9 in total) cultured in vitro. The fetuses in families 1 and 6 (via PGT-M) were both confirmed to be healthy by follow up, whilst the mothers from families 2 and 3 had chosen induced labor. CONCLUSION Haplotype analysis based on STR/SNP is an effective method for judging gonad mosaicism. Gonad mosaicisms should be suspected for women who have given births to children with DMD gene variants but with a normal peripheral blood genotype. Prenatal diagnosis and reproductive intervention may be adapted to reduce the births of further affected children in such families.
Male ; Pregnancy ; Child ; Humans ; Female ; Muscular Dystrophy, Duchenne/diagnosis* ; Dystrophin/genetics* ; Mosaicism ; Exons ; Prenatal Diagnosis/methods* ; Nucleotides

OBJECTIVE: To explore the genetic basis for a fetus with severe heart defect and mosaic trisomy 12, and the correlation between chromosomal abnormalities and clinical manifestations and pregnancy outcome. METHODS: A 33-year-old pregnant woman who presented at Lianyungang Maternal and Child Health Care Hospital on May 17, 2021 due to abnormal fetal heart development revealed by ultrasonography was selected as the study subject. Clinical data of the fetus were collected. Amniotic fluid sample of the pregnant women was collected and subjected to G-banded chromosomal karyotyping and chromosomal microarray analysis (CMA). The CNKI, WanFang and PubMed databases were searched with key words, with the retrieval period set as from June 1, 1992 to June 1, 2022. RESULTS: For the 33-year-old pregnant woman, ultrasonography at 22+6 gestational weeks had revealed abnormal fetal heart development and ectopic pulmonary vein drainage. G-banded karyotyping showed that the fetus has a karyotype of mos 47,XX,+12[1]/46,XX[73], with the mosaicism rate being 1.35%. CMA results suggested that about 18% of fetal chromosome 12 was trisomic. A newborn was delivered at 39 weeks of gestation. Follow-up confirmed severe congenital heart disease, small head circumference, low-set ears and auricular deformity. The infant had died 3 months later. The database search has retrieved 9 reports. Literature review suggested that the liveborn infants with mosaic trisomy 12 had diverse clinical manifestations depending on the affected organs, which had included congenital heart disease and/or other organs and facial dysmorphisms, resulting in adverse pregnancy outcomes. CONCLUSION Trisomy 12 mosaicism is an important factor for severe heart defects. The results of ultrasound examination have important value for evaluating the prognosis of the affected fetuses.
Infant, Newborn ; Child ; Pregnancy ; Female ; Humans ; Adult ; Trisomy/genetics* ; Amniocentesis/methods* ; Chromosome Disorders ; Mosaicism ; Fetus ; Heart Defects, Congenital/genetics*

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) and fluorescence in situ hybridization (FISH) for the prenatal diagnosis of chromosomal mosaicisms. METHODS: A total of 775 pregnant women who had visited the Prenatal Diagnosis Center of Yancheng Maternal and Child Health Care Hospital from January 2018 to December 2020 were selected as study subjects. Chromosome karyotyping analysis and CMA were carried out for all women, and FISH was used to validate the suspected mosaicism cases. RESULTS: Among the 775 amniotic fluid samples, karyotyping has identified 13 mosaicism cases, which yielded a detection rate of 1.55%. Respectively, there were 4, 3, 4 and 2 cases for sex chromosome number mosaicisms, abnormal sex chromosome structure mosaicisms, abnormal autosomal number mosaicisms and abnormal autosomal structure mosaicisms. CMA has only detected only 6 of the 13 cases. Among 3 cases verified by FISH, 2 cases were consistent with the karyotyping and CMA results, and clearly showed low proportion mosaicism, and 1 case was consistent with the result of karyotyping but with a normal result by CMA. Eight pregnant women had chosen to terminate the pregnancy (5 with sex chromosome mosaicisms and 3 with autosomal mosaicisms). CONCLUSION For fetuses suspected for chromosomal mosaicisms, CMA, FISH and G-banding karyotyping should be combined to determine the type and proportion of mosaicisms more precisely in order to provide more information for genetic counseling.
Female ; Pregnancy ; Humans ; Mosaicism ; In Situ Hybridization, Fluorescence ; Chromosome Disorders/genetics* ; Prenatal Diagnosis/methods* ; Chromosome Aberrations ; Sex Chromosome Aberrations ; Microarray Analysis/methods* ; Chromosomes