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

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.

Klinefelter Syndrome in Childhood: Variability in Clinical and Molecular Findings

OBJECTIVE

Klinefelter syndrome (KS) is the most common (1/500–1/1000) chromosomal disorder in males, but only 10% of cases are identified in childhood. This study aimed to review the data of children with KS to assess the age and presenting symptoms for diagnosis, clinical and laboratory findings, together with the presence of comorbidities.

METHODS

Twenty-three KS patients were analyzed retrospectively. Age at admission, presenting symptoms, comorbid problems, height, weight, pubertal status, biochemical findings, hormone profiles, bone mineral density and karyotype were evaluated. Molecular analysis was also conducted in patients with ambiguous genitalia.

RESULTS

The median age of patients at presentation was 3.0 (0.04-16.3) years. Most of the cases were diagnosed prenatally (n=15, 65.2%). Other reasons for admission were scrotal hypospadias (n=3, 14.3%), undescended testis (n=2, 9.5%), short stature (n=1, 4.8%), isolated micropenis (n=1, 4.8%) and a speech disorder (n=1, 4.8%). The most frequent clinical findings were neurocognitive disorders, speech impairment, social and behavioral problems and undescended testes. All except two patients were prepubertal at admission. Most of the patients (n=20, 86.9%) showed the classic 47,XXY karyotype. Steroid 5 alpha-reductase 2 gene and androgen receptor gene mutations were detected in two of the three cases with genital ambiguity.

CONCLUSION

Given the large number of underdiagnosed KS patients before adolescence, pediatricians need to be aware of the phenotypic variability of KS in childhood. Genetic analysis in KS patients may reveal mutations associated with other forms of disorders of sex development besides KS.

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.

Androgen insensitivity syndrome and Klinefelter's syndrome: sex and gender considerations

Two of the most common intersex conditions, androgen insensitivity and Klinefelter's syndrome, are described with an emphasis on aspects that are of relevance to psychiatrists. Attention is focused on commonalities and differences between these syndromes and particular attention is given to how persons who have these conditions manifest sexual and gender adjustments to their situations. Tips on counseling and medical management are offered.

Constitutive activation of the androgen receptor by a point mutation in the hinge region: a new mechanism for androgen-independent growth in prostate cancer

Androgen receptor (AR) mutations that modify both the ligand binding and the transactivation capacities of the AR represent one of the mechanisms involved in the transition of prostate cancer (PCa) from androgen-dependent to androgen-independent growth. We use a yeast-based functional assay to detect and analyze mutant ARs in PCa. We report the detection of 2 different mutant ARs within the same metastatic tumour sample harvested in a patient with advanced PCa who had escaped androgen deprivation. Concomitantly to the widely described T877A mutant AR, we identified an additional double mutant AR harboring the nonsense mutation Q640Stop just downstream the DNA binding domain together with the T877A point mutation. This type of mutation, which leads to a c-terminal truncated AR, has not been described yet in PCa. Using luciferase reporter assays we demonstrated that this truncated AR exhibited constitutive transactivation properties. In conclusion, our data suggest that mutation-induced constitutive activation of the AR could be a mechanism used by PCa cells to escape androgen deprivation.

An SRY-negative 47,XXY mother and daughter

Females with XY gonadal dysgenesis are sterile, due to degeneration of the initially present ovaries into nonfunctional streak gonads. Some of these sex-reversal cases can be attributed to mutation or deletion of the SRY gene. We now describe an SRY-deleted 47,XXY female who has one son and two daughters, and one of her daughters has the same 47,XXY karyotype. PCR and FISH analysis revealed that the mother carries a structurally altered Y chromosome that most likely resulted from an aberrant X-Y interchange between the closely related genomic regions surrounding the gene pair PRKX and PRKY on Xp22.3 and Yp11.2, respectively. As a consequence, Yp material, including SRY, has been replaced by terminal Xp sequences up to the PRKX gene. The fertility of the XXY mother can be attributed to the presence of the additional X chromosome that is missing in XY gonadal dysgenesis females. To our knowledge, this is the first human XXY female described who is fertile.

Point mutations in the steroid-binding domain of the androgen receptor gene of five Japanese patients with androgen insensitivity syndrome

We analyzed the androgen receptor (AR) gene in five Japanese patients diagnosed with androgen insensitivity syndrome (AIS). All AR genes from the five patients had single-nucleotide substitutions, which introduced a premature termination codon in three patients (Gln640, Arg752, and Gln640 and Trp751), and a single amino acid substitution in two patients (Arg831 to Gln, and Leu812 to Phe). All the mutations occurred in the steroid-binding domain, comprising exons D through G. The three patients with the premature termination codon(s) and the one patient with Arg831Gln were clinically diagnosed as having complete AIS, while the patient with Leu812Phe had a partial form of AIS. Pubic skin fibroblasts from four of the five patients did not show detectable androgen binding. These data on mutations that have not been reported previously, provide valuable information for the further characterization of structural and functional relationships in the steroid-binding domain of the AR protein.