Down syndrome in association with features of the androgen insensitivity syndrome

Association between Down Syndrome and Disorders of Sex Development: Report of Three Cases and Review of 188 Cases in the Literature

In this study, we present 3 cases of Down syndrome (DS) associated with disorders/differences of sex development (DSD) and review the literature on this topic. Case 1: 1-year-old child with male genitalia and DS phenotype, 47,XX,+21 karyotype and testicular DSD. Case 2: 11-month-old child with male genitalia and few DS dysmorphisms, 45,X/47,XY,+21 karyotype, and mixed gonadal dysgenesis. Case 3: 4-month-old child with female genitalia and DS phenotype, 47,XY,+21 karyotype and XY complete gonadal dysgenesis. In the literature, among 188 patients, 107 (57%) had Klinefelter syndrome and 61 (33%) Turner syndrome, 12 (6%) had mixed gonadal dysgenesis, 2 (1%) had partial androgen insensitivity, 2 (1%) ovotesticular DSD, and the others had congenital adrenal hyperplasia, XY partial gonadal dysgenesis, XY complete gonadal dysgenesis, and complete androgen insensitivity (1 case each). A typical DS phenotype was found in all individuals of the revision, with the exception of one case, but DSD features were not always reported. In conclusion, the association of DS with sex chromosome DSD is the most frequently observed, whereas associations with 46,XX and 46,XY DSD is extremely rare.

Severe hypospadias associated with Robertsonian translocation

In this study, we report a 3-year-old boy with severe scrotal hypospadias with Robertsonian translocation [45,XY,t(13q;14q)]. The patient was born at term with a low birth weight and hypospadias. There was no endocrinological abnormality. His father also has a balanced 13-14 Robertsonian translocation. Two-stage hypospadias repair was carried out. The presence of this chromosomal anomaly and hypospadias are unique to our patient, compared to others with the 45,XY,t(13q;14q) translocation. Although no such association has been reported so far, we thought that severe hypospadias in this case might be associated with this translocation.

A novel point mutation of the androgen receptor (F804L) in an Egyptian newborn with complete androgen insensitivity associated with congenital glaucoma and hypertrophic pyloric stenosis

Androgen-insensitivity syndrome (AIS) is a major cause of male pseudohermaphroditism (MPH). Although AIS is usually reported as a monogenic disease resulting from androgen receptor (AR) mutations, on rare occasions it has been observed as part of a multiple congenital anomaly syndrome. We report here a patient who was the first newborn girl of an unrelated couple. Shortly after birth, the diagnoses of congenital glaucoma and pyloric stenosis were made. A detailed history of the father's family revealed that nine members presented glaucoma before 40 years of age. Clinical and ultrasound evaluation showed two inguinal testes, with female external genitalia and no Mullerian derivatives. The patient had a 46,XY karyotype, good testicular response to gonadotrophin stimulation and a remarkably high T : dihydrotestosterone ratio. Sequencing of the five exons of the 5alpha-reductase type 2 gene (SRD5A2) was normal. Conversely, a de novo point mutation was found in exon 6 of the AR gene, resulting in an F804L substitution, which has never been described previously. To our knowledge, the association of complete AIS, congenital glaucoma and pyloric stenosis has also never been reported previously.

Developmental arrest of germ cells in the pathogenesis of germ cell neoplasia

Clinical observations and epidemiological evidence suggest that important aetiopathological events that cause neoplastic transformation of the male germ cell may occur in fetal life or early infancy. The incidence of germ cell neoplasia is high in individuals with various disorders of gonadal development and sexual differentiation, such as gonadal dysgenesis or androgen insensitivity syndrome. Increased risk has also been noted in individuals with trisomy 21, idiopathic infertility and low birth weight. Infertility is sometimes associated with small aberrations of sex chromosomes (e.g. low frequency mosaicism XY/XO) which can also be found in patients with testicular cancer. The variety of conditions that predispose to testicular neoplasia and the rise in its incidence in many countries speaks for the influence of environmental factors which may affect genetically predisposed individuals. We hypothesise that if the development of the testis is disturbed or delayed, primordial germ cells or gonocytes undergo maturation delay or differentiation arrest which may render them susceptible to neoplastic transformation. Morphologically homogenous premalignant carcinoma in situ (CIS) cells have the potential to differentiate into a variety of histological forms of overt testicular tumours. Analysis of cell surface antigens expressed by CIS cells found in the vicinity of pure and mixed tumours demonstrates that CIS cells are phenotypically heterogeneous. Comparison of the phenotypes of CIS cells, primordial germ cells, human embryonal carcinoma cells and closely related primate embryonal stem cells reveals various similarities but also differences. We speculate that phenotypical heterogeneity of CIS cells may be associated with their potential to give rise to different tumour types, and may be related to the developmental stage of the early germ cell which has undergone malignant transformation.