GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults.

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

Linkage analysis of a kindred with inherited 46,XY partial gonadal dysgenesis.

We have reported a kindred in which 46,XY gonadal dysgenesis was inherited in an X-linked (or autosomal dominant sex-limited) manner and in which affected subjects did not have a large duplication of the short arm of the X-chromosome. In the present study we used linkage and sequence analyses to test the role of X-linked and various autosomal genes in the etiology of the familial 46,XY partial gonadal dysgenesis. For analysis of X-linkage, 28 microsatellite polymorphisms and 1 restriction fragment length polymorphism were studied. The genotypes of informative family members were determined at each locus, and data were analyzed. Despite the large number of loci tested, our studies did not establish linkage between the trait and an X-chromosomal locus. With respect to the study of autosomal genes, linkage analysis using a polymorphism within the 3'-untranslated region of the WT1 gene excluded involvement of WT-1 in the etiology of the abnormal gonadal differentiation of the family in this study. Similarly, linkage analysis using four microsatellites on the distal short arm of chromosome 9 was not consistent with linkage. Linkage analysis of a locus close to the SOX9 gene as well as analysis of the coding region of the SOX9 gene suggested that this gene was not associated with the trait in the affected subjects we studied. Our data suggest the role of an autosomal gene in the abnormal gonadal differentiation in the family in the study, but do not formally exclude the role of an X-chromosome gene.

Loss of sequences 3' to the testis-determining gene, SRY, including the Y pseudoautosomal boundary associated with partial testicular determination.

The condition termed 46,XY complete gonadal dysgenesis is characterized by a completely female phenotype and streak gonads. In contrast, subjects with 46,XY partial gonadal dysgenesis and those with embryonic testicular regression sequence usually present ambiguous genitalia and a mix of Müllerian and Wolffian structures. In 46,XY partial gonadal dysgenesis gonadal histology shows evidence of incomplete testis determination. In 46,XY embryonic testicular regression sequence there is lack of gonadal tissue on both sides. Various lines of evidence suggest that embryonic testicular regression sequence is a variant form of 46,XY gonadal dysgenesis. The sex-determining region Y chromosome gene (SRY) encodes sequences for the testis-determining factor. To date germ-line mutations in SRY have been reported in approximately 20% of subjects with 46,XY complete gonadal dysgenesis. However, no germ-line mutations of SRY have been reported in subjects with the partial forms. We studied 20 subjects who presented either 46,XY partial gonadal dysgenesis or 46,XY embryonic testicular regression sequence. We examined the SRY gene and the minimum region of Y-specific DNA known to confer a male phenotype. The SRY-open reading frame (ORF) was normal in all subjects. However a de novo interstitial deletion 3' to the SRY-ORF was found in one subject. Although it is possible that the deletion was unrelated to the subject's phenotype, we propose that the deletion was responsible for the abnormal gonadal development by diminishing expression of SRY. We suggest that the deletion resulted either in the loss of sequences necessary for normal SRY expression or in a position effect that altered SRY expression. This case provides further evidence that deletions of the Y chromosome outside the SRY-ORF can result in either complete or incomplete sex reversal.

Abnormal gonadal differentiation in two subjects with ambiguous genitalia, Mullerian structures, and normally developed testes: evidence for a defect in gonadal ridge development.

Among a group of patients with abnormal sexual differentiation, we have identified two subjects who had a 46,XY karyotype, ambiguous genitalia, and well-developed Müllerian structures, but normal appearing testes. The presence of ambiguous genitalia and persistent Müllerian structures implied both Leydig cell and Sertoli cell dysfunction, hence, gonadal dysgenesis. However, the normal testicular histology suggested that the underlying abnormality was not a defect in testis determination itself but an abnormality in timing of gonadal ridge and testis development. In one of the two subjects genomic DNA was available. The sequence of the SRY gene was normal. Because rare patients with partial androgen insensitivity may have a similar phenotype, the AR gene was evaluated by denaturing gradient gel electrophoresis (DGGE) and was normal. Some subjects with mutation of the WT1 gene or with deletion of the distal short arm of chromosome 9 may have similar phenotypes. The WT1 gene was studied by single-strand conformation polymorphism (SSCP) analysis and was normal. In addition, there was no loss of heterozygosity of polymorphic markers in distal 9p. The gene for Müllerian inhibiting substance (MIS) was also studied by SSCP and was normal. Although the exact mechanism for the defect in the two subjects is unknown, it may be due to an abnormality in a gene or genes involved in the timing of gonadal ridge development.

Assay of plasma testosterone during the first six months of life: importance of chromatographic purification of steroids.

Determination of the plasma concentration of testosterone (T) is important in evaluating infants born with ambiguous genitalia and micropenis, and several commercially available kits provide a direct assay of T in unextracted plasma. Using plasma samples obtained from 36 subjects < 6 months old, we compared the concentration of plasma T measured by RIA after extraction and purification by column chromatography with the T concentration measured in a direct assay. When aliquots of samples were purified before RIA, the concentration of T was markedly lower than in the direct assay. In the first 3 weeks postpartum, results of the direct assay were 3.8-fold greater than those obtained after purification. This difference decreased over time, and by age 2 months there was fairly good agreement between the two methods. These data indicate that some direct assays of plasma T are inappropriate during the first 2 months postpartum.

Combined Leydig cell and Sertoli cell dysfunction in 46,XX males lacking the sex determining region Y gene.

We have evaluated 3 individuals with a rare form of 46,XX sex reversal. All of them had ambiguous external genitalia and mixed wolffian and müllerian structures, indicating both Leydig cell and Sertoli cell dysfunction, similar to that of patients with true hermaphroditism. However, gonadal tissue was not ovotesticular but testicular with varying degrees of dysgenesis. SRY sequences were absent in genomic DNA from peripheral leukocytes in all 3 subjects. Y centromere sequences were also absent, indicating that testis development did not occur because of a low level mosaicism of Y bearing cells. The subjects in this report demonstrate that there is a continuum in the extent of testis determination in SRY-negative 46,XX sex reversal, ranging from nearly normal to minimal testicular development.