The same mutation affecting the splicing of WT1 gene is present on Frasier syndrome patients with or without Wilms' tumor.

Denys-Drash and Frasier syndromes are rare human disorders that associate nephropathy with gonadal and genital abnormalities. In DDS there is a predisposition to Wilms' tumor. Heterozygous point mutations in the Wilms' tumor, type1 gene (WT1), particularly those altering the zinc finger (ZF) encoding exons, have been reported in most DDS patients, while mutations in intron 9 of the same gene cause FS. This paper describes two cases of DDS, one FS and one patient with Wilm's tumor and intersex genitalia, in which mutations were searched by sequencing the exons 8 and 9 of WT1 gene. Patient 1 carried a missense point mutation in exon 8 (ZF2), converting a CGA-Arg codon to a TGA-stop codon. Patient 2 presented a single nucleotide deletion within exon 9 (ZF3) introducing a premature chain termination at codon 398. Patients 3 and 4 had a C-->T transition at position +4 of the second alternative splice donor site of exon 9 (this mutation was detected in peripheral blood and in tumor derived DNA of patient 3). However, patient 3 had previously developed a Wilms' tumor. This is the first case of Wilms' tumor development in a phenotypically and genetically confirmed case of FS.

Hypertelorism and hypospadias associated with a de novo apparently balanced translocation between 8q22.3-23 and 20p13.

A de novo apparently balanced translocation involving chromosomes 8 and 20 was found in a 14-year-old boy with minor anomalies, mild skeletal abnormalities and ambiguous external genitalia including perineoscrotal hypospadias, rudimentary fused labioscrotal folds, bilateral cryptorchidism, and small penis. The karyotype was 46,XY, t(8;20)(q22.3-23;p13). No signs of other conditions known to be associated with structural anomalies of either chromosome 8 or 20 were present and incomplete masculinisation of the external genitalia appears to be the main component of the phenotype. Clinical and biological studies showed apparently normal testicular function in utero and after birth. Examinations excluded 5 alpha-reductase deficiency or a block in any enzymatic steps of testosterone, glucocorticoid and mineralocorticoid biosynthesis. Coding sequences of the sex-determining gene (SRY) and androgen receptor gene (AR) were found to be identical to those of a normal male excluding their role in the cause of the present condition. Since several other reports describe the association of hypospadias and hypertelorism with deletions or translocations involving 8q, we suggest that a locus necessary for male sex differentiation is located at distal 8q.

Testicular development in an SRY-negative 46,XX individual harboring a distal Xp deletion.

A case of a true hermaphrodite presenting with a karyotype of 46,X,del(X)(p21.1-->pter) is described. The testis-determining gene, SRY, was not detected in DNA prepared from either peripheral blood lymphocytes or from a gonad biopsy. The patient also presented with a series of discrete somatic abnormalities, including abnormal skin and retinal pigmentation, and mental retardation. The extent of the Xp deletion was mapped by Southern blotting. X chromosome replication studies of lymphoblast cells prepared from the patient indicated that the deleted X chromosome was inactivated in all cells examined. It is suggested that the phenotype of the patient is caused by the unmasking of a recessive allele(s) on the grossly intact X chromosome. The relationship between the Xp deletion, the intersex phenotype, and the possible role of an Xp locus involved in human sex determination is discussed.