A case of complete testicular feminisation and 47,XXY karyotype

A 47,XXY Pregnant Woman without the SRY Gene

Individuals with a 47,XXY karyotype usually present with a male phenotype due to the additional Y chromosome. In this paper, we describe a 47,XXY female who was pregnant with a fetus of the same karyotype based on chromosome analysis of amniotic fluid cells. Further analysis of her Y chromosome indicated that the additional Y chromosome contains no SRY gene on the short arm but carries the azoospermia factor region on the long arm, including azoospermia factor a, b and c (AZFa, AZFb, AZFc). This region may influence her female phenotype. Fertile females with a 47,XXY karyotype and loss of SRY are extremely rare. This paper is the first report of a 47,XXY pregnant woman with a normal phenotype and may enrich our knowledge on 47,XXY individuals.

Perspectives in Pediatric Pathology, Chapter 6. Male Undermasculinization

Normal male development requires three conditions: (1) adequate differentiation of the fetal testis; (2) synthesis and secretion of testicular hormones; and (3) effective action of these hormones on target organs. This requires the combined action of the inhibitory anti-müllerian hormone (AMH, secreted by Sertoli cells) to block the development of the uterus and fallopian tubes from the müllerian duct, together with the trophic stimulus of testosterone (a Leydig cell product), which leads to virilization of the wolffian ducts. Additionally, the development of external genitalia depends on the conversion of testosterone to dihydrotestosterone by the enzyme 5-α-reductase. Failure of any of these mechanisms leads to deficient virilization or the so-called "male pseudohermaphroditism" syndromes.

Chromosomal variants in klinefelter syndrome

Klinefelter syndrome (KS) describes the phenotype of the most common sex chromosome abnormality in humans and occurs in one of every 600 newborn males. The typical symptoms are a tall stature, narrow shoulders, broad hips, sparse body hair, gynecomastia, small testes, absent spermatogenesis, normal to moderately reduced Leydig cell function, increased secretion of follicle-stimulating hormone, androgen deficiency, and normal to slightly decreased verbal intelligence. Apart from that, amongst others, osteoporosis, varicose veins, thromboembolic disease, or diabetes mellitus are observed. Some of the typical features can be very weakly pronounced so that the affected men often receive the diagnosis only at the adulthood by their infertility. With a frequency of 4%, KS is described to be the most common genetic reason for male infertility. The most widespread karyotype in affected patients is 47,XXY. Apart from that, various other karyotypes have been described, including 46,XX in males, 47,XXY in females, 47,XX,der(Y), 47,X,der(X),Y, or other numeric sex chromosome abnormalities (48,XXXY, 48,XXYY, and 49,XXXXY). The focus of this review was to abstract the different phenotypes, which come about by the various karyotypes and to compare them to those with a 'normal' KS karyotype. For that the patients have been divided into 6 different groups: Klinefelter patients with an additional isochromosome Xq, with additional rearrangements on 1 of the 2 X chromosomes or accordingly on the Y chromosome, as well as XX males and true hermaphrodites, 47,XXY females and Klinefelter patients with other numeric sex chromosome abnormalities. In the latter, an almost linear increase in height and developmental delay was observed. Men with an additional isochromosome Xq show infertility and other minor features of 'normal' KS but not an increased height. Aside from the infertility, in male patients with other der(X) as well as der(Y) rearrangements and in XXY women no specific phenotype is recognizable amongst others due to the small number of cases. The phenotype of XX males depends on the presence of SRY (sex-determining region Y) and the level of X inactivation at which SRY-negative patients are generally rarely observed.

Molecular studies of a patient with complete androgen insensitivity and a 47,XXY karyotype

A phenotypic female with complete androgen insensitivity from a maternally inherited mutation in the androgen receptor had a 47,XXY karyotype. Partial maternal X isodisomy explained the expression of androgen insensitivity despite the presence of 2 X chromosomes.

Genital Anomalies in Klinefelter’s Syndrome

BACKGROUND/AIMS

Klinefelter's syndrome is characterized by progressive testicular failure causing aspermatogenesis and androgen deficiency. Klinefelter patients classically have complete male sex differentiation, and genital anomalies are generally not recognized as associated features of the syndrome.

METHODS

We reviewed the cases of Klinefelter's syndrome with genitalia abnormalities from the Cambridge Disorders of Sex Development Database, and also reviewed previous case reports of genital anomalies associated with Klinefelter's syndrome and its variants.

RESULTS

We present seven Klinefelter patients with abnormalities of the genitalia, ranging from mild anomalies (chordee) to moderate undervirilisation (bifid scrotum and perineal hypospadias). Two cases were true hermaphrodites with karyotypes 47,XXY and 47,XXY/46,XX respectively. Though androgen insensitivity has been postulated previously as a possible pathogenic mechanism, we demonstrated normal androgen binding in 3 cases in which this was studied. Review of other case reports revealed a range of mild-to-severe abnormalities as well as cases reported as sex reversal, testicular feminization, and true hermaphroditism.

CONCLUSION

Genital anomalies are not commonly observed in Klinefelter's syndrome. However, it is important to acknowledge the association, and recognize Klinefelter's syndrome as one of the causes of abnormal genitalia at birth.

Complete androgen insensitivity in a 47,XXY patient with uniparental disomy for the X chromosome

We describe a unique patient with complete androgen insensitivity syndrome and a 47,XXY karyotype. Androgen receptor assay using cultured pubic skin fibroblasts showed no androgen-binding capacity. Sequence analysis of the androgen receptor gene demonstrated two nonsense mutations, one in exon D and one in exon E. Microsatellite marker analysis showed that the patient is homozygous for all five Xq loci examined. The results suggest that the long-arms of the two X chromosomes are identical, i.e., uniparental isodisomy at least for Xq, and carry the same mutations in the androgen receptor gene. This explains how complete androgen insensitivity syndrome occurred in this 47,XXY individual.

A 47,XXY female with unusual genitalia

A 47,XXY karyotype was found in a 6-year-old girl. The patient had female external genitalia, clitoromegaly, remnants of the ductus mesonephricus, uterus, and gonads in the labia majora which were determined to be testes by histology. Cytogenetic and DNA analyses suggest that the Y chromosome had a normal structure and that both X chromosomes were of maternal origin. The unusual clinical findings in the patient are discussed.

Maternal meiosis II nondisjunction in a case of 47,XXY testicular feminization

An 11-year-old patient with incomplete testicular feminization and a 47,XXY karyotype is described. The patient had female external genitalia, clitoromegaly, and some features of Klinefelter's syndrome, including speech delay and delayed intellectual development. DNA analysis using X chromosomal DNA sequences suggest that the supernumerary X chromosome in the patient resulted from maternal nondisjunction during meiosis II. The M II error thereby provides the basis for homozygosity of a mutation in the androgen receptor locus.

Expression of a mutant androgen receptor in cloned fibroblasts derived from a heterozygous carrier for the syndrome of testicular feminization

Thermolability of androgen binding was compared in fibroblasts cloned from normal female skin, skin from a subject with testicular feminization whose mutation is known to be associated with a thermolabile androgen receptor, and from the mother of the subject with testicular feminization. Seven of 28 clones studied from the mother exhibited thermolability of binding, indicating that the mutant gene that causes thermolability of binding, like the gene responsible for the normal androgen receptor, is X-linked.