Sex-determining region Y (SRY) in a patient with 46,XX true hermaphroditism

Sporadic Creutzfeldt-Jakob Disease in a Woman Married Into a Gerstmann-Sträussler-Scheinker Family: An Investigation of Prions Transmission via Microchimerism

This is the first report of presumed sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Sträussler-Scheinker disease (GSS) with the prion protein gene c.305C>T mutation (p.P102L) occurring in one family. The father and son were affected with GSS and the mother had a rapidly progressive form of CJD. Diagnosis of genetic, variant, and iatrogenic CJD was ruled out based on the mother's clinical history, genetic tests, and biochemical investigations, all of which supported the diagnosis of sCJD. However, given the low incidence of sCJD and GSS, their co-occurrence in one family is extraordinary and challenging. Thus, a hypothesis for the transmission of infectious prion proteins (PrPSc) via microchimerism was proposed and investigated. DNA from 15 different brain regions and plasma samples of the CJD patient was subjected to PCR and shallow sequencing for detection of a male sex-determining chromosome Y (chr. Y). However, no trace of chr. Y was found. A long CJD incubation period or presumed small concentrations of chr. Y may explain the obtained results. Further studies of CJD and GSS animal models with controlled genetic and proteomic features are needed to determine whether maternal CJD triggered via microchimerism by a GSS fetus might present a new PrPSc transmission route.

Extracellular vesicles impose quiescence on residual hematopoietic stem cells in the leukemic niche

Progressive remodeling of the bone marrow microenvironment is recognized as an integral aspect of leukemogenesis. Expanding acute myeloid leukemia (AML) clones not only alter stroma composition, but also actively constrain hematopoiesis, representing a significant source of patient morbidity and mortality. Recent studies revealed the surprising resistance of long-term hematopoietic stem cells (LT-HSC) to elimination from the leukemic niche. Here, we examine the fate and function of residual LT-HSC in the BM of murine xenografts with emphasis on the role of AML-derived extracellular vesicles (EV). AML-EV rapidly enter HSC, and their trafficking elicits protein synthesis suppression and LT-HSC quiescence. Mechanistically, AML-EV transfer a panel of miRNA, including miR-1246, that target the mTOR subunit Raptor, causing ribosomal protein S6 hypo-phosphorylation, which in turn impairs protein synthesis in LT-HSC. While HSC functionally recover from quiescence upon transplantation to an AML-naive environment, they maintain relative gains in repopulation capacity. These phenotypic changes are accompanied by DNA double-strand breaks and evidence of a sustained DNA-damage response. In sum, AML-EV contribute to niche-dependent, reversible quiescence and elicit persisting DNA damage in LT-HSC.

The Spectrum of Ovotesticular Disorders of Sex Development in South Africa: A Single-Centre Experience

OBJECTIVE

To describe the clinical characteristics, biochemistry, histopathology, and long-term outcomes in subjects with ovotesticular (OT) disorder of sex development (DSD).

STUDY DESIGN

This is a retrospective subset analysis of 64 cases of histologically confirmed OT DSD.

RESULTS

All subjects were South African; 97% (n = 62) were African and 92% (n = 59) were of Zulu ethnicity. The most common karyotype was 46,XX (88%; n = 56), followed by 46,XY (8%), 46,XY/45,X (3%), and 46,XX/46,XY (1%). The median age at presentation was 7 months (0.5 months to 5.1 years). Sixty-one of the subjects (95%) presented with DSD. The ovotestis was the most frequent gonad (56%), followed by the ovary (23%) and the testis (16%). Testes were more commonly located on the right and ovaries on the left (p < 0.0001). The male gender was the predominant sex of rearing in two-thirds of the subjects. Gender dysphoria was noted in 8 subjects (11%) at a median of 6.4 (4.3-9.3) years. Long-term follow-up (n = 14) revealed spontaneous puberty in 5 subjects, gender dysphoria in 2 subjects, and neuropsychiatric disorders in 4 subjects.

CONCLUSION

OT DSD is an important differential diagnosis in Black South Africans with 46,XX DSD.

Methods for the Study of Gonadal Development

Current knowledge on gonadal development and sex determination is the product of many decades of research involving a variety of scientific methods from different biological disciplines such as histology, genetics, biochemistry, and molecular biology. The earliest embryological investigations, followed by the invention of microscopy and staining methods, were based on histological examinations. The most robust development of histological staining techniques occurred in the second half of the nineteenth century and resulted in structural descriptions of gonadogenesis. These first studies on gonadal development were conducted on domesticated animals; however, currently the mouse is the most extensively studied species. The next key point in the study of gonadogenesis was the advancement of methods allowing for the in vitro culture of fetal gonads. For instance, this led to the description of the origin of cell lines forming the gonads. Protein detection using antibodies and immunolabeling methods and the use of reporter genes were also invaluable for developmental studies, enabling the visualization of the formation of gonadal structure. Recently, genetic and molecular biology techniques, especially gene expression analysis, have revolutionized studies on gonadogenesis and have provided insight into the molecular mechanisms that govern this process. The successive invention of new methods is reflected in the progress of research on gonadal development.

Familial lethal inheritance of a mutated paternal gene in females causing X-linked ornithine transcarbamylase (OTC) deficiency

A Leu148Phe substitution of the ornithine transcarbamylase (OTC) gene was identified in a 2-year-old girl with OTC deficiency (14% of control). Her two elder sisters died in childhood of hyperammonemia, and the patient also died of OTC deficiency. Enzyme activity in Cos1 cells transfected by the mutant cDNA was undetectable, thereby indicating a definite pathogenic mutation. Familial gene analysis showed that the mother had wild-type OTC alleles on both X-chromosomes and the father was a mosaic for the mutant allele in his lymphocytes and spermatozoa. This clinical case shows that a somatic and germline mosaicism for a single-gene disorder led to an unusual pattern of X-linked inheritance in the family, and all three daughters in the family died of OTC deficiency. The possibility that inherited factors will lead to skewed X-inactivation needs to be considered.

Prenatal monitoring in a family at high risk for ornithine transcarbamylase (OTC) deficiency: a new mutation of an A-to-C transversion in position +4 of intron 1 of the OTC gene that is likely to abolish enzyme activity

DNA analysis of a male propositus with ornithine transcarbamylase (OTC) deficiency documented an A-to-C substitution in position +4 of intron 1. No other abnormalities were observed in the OTC gene, or at 563 bp upstream of the 5' site, which included a promoter region, or at 383 bp downstream of the termination codon, which included a polyadenylation signal sequence. This mutation produces an RsaI site in the sequence, which was used for prenatal monitoring in the fourth and fifth pregnancies. DNA from amniotic cells in the former case were positive for RsaI digestion and the SRY gene (sex determinant region Y), indicating hemizygosity for the mutant allele. OTC activity was not measurable, and mRNA of the OTC gene was not detected by Northern blotting in the affected fetal liver. RT-PCR (reverse transcription-PCR) demonstrated only the wild-type allele. Thus, the mutation interferes with RNA processing, and an extremely low amount of normally spliced mRNA for the OTC gene seems to have caused the disease in our patient. The fetus of the fifth pregnancy was a normal male, as confirmed postnatally.

A true hermaphrodite with bilateral ovotestes: a case report

A 20-month-old phenotypically male child with ambiguous external genitalia came to this hospital. Chromosomal and DNA analyses revealed 46/XX karyotype and absence of SRY gene, respectively. Two gonadal masses in the labioscrotal folds histologically showed both ovarian and testicular tissues. Clinicopathological features of the patient suggested true hermaphroditism with bilateral ovotestes.