John W. Honour

HETEROGENEITY OF THE POLYCYSTIC OVARY SYNDROME: CLINICAL, ENDOCRINE AND ULTRASOUND FEATURES IN 556 PATIENTS

This paper reports an analysis of the clinical, endocrine and ultrasound data within a population of 556 patients with ultrasound‐diagnosed polycystic ovaries. Compared with those not so affected, hirsutism was associated with a higher mean serum testosterone concentration, infertility was associated with higher mean gonadotrophin concentrations, obesity was associated with a higher mean serum testosterone concentration, hyperprolactinaemia was associated with a lower mean serum testosterone concentration and smaller ovaries, alopecia was associated with lower mean serum LH and testosterone concentrations, and acanthosis nigricans was associated with obesity and a raised mean serum testosterone concentration. The heterogeneity illustrates the limitations in the use of specific clinical or endocrine criteria as requirements for the diagnosis of the polycystic ovary syndrome.

Size at birth and adrenocortical function in childhood

OBJECTIVE The mechanisms underlying the association between reduced size at birth and cardiovascular disease and non‐insulin‐dependent diabetes mellitus in adult life are not known. One possibility is that the intra‐uterine environment has permanent effects on the function or activity of the hypothalamo‐pituitary‐adrenal axis. We tested this by relating size at birth to the urinary excretion of adrenal androgen and glucocorticoid metabolites in a population sample of 9‐year‐old children.

Evidence for digenic inheritance in some cases of Antley-Bixler syndrome?

The Antley-Bixler syndrome has been thought to be caused by an autosomal recessive gene. However, patients with this phenotype have been reported with a new dominant mutation at theFGFR2 locus as well as in the offspring of mothers taking the antifungal agent fluconazole during early pregnancy. In addition to the craniosynostosis and joint ankylosis which are the clinical hallmarks of the condition, many patients, especially females, have genital abnormalities. We now report abnormalities of steroid biogenesis in seven of 16 patients with an Antley-Bixler phenotype. Additionally, we identify FGFR2 mutations in seven of these 16 patients, including one patient with abnormal steroidogenesis. These findings, suggesting that some cases of Antley-Bixler syndrome are the outcome of two distinct genetic events, allow a hypothesis to be formulated under which we may explain all the differing and seemingly contradictory circumstances in which the Antley-Bixler phenotype has been recognised.

Menstrual disturbance and hypersecretion of progesterone in women with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

OBJECTIVE While menstrual disturbance is often quoted as a feature of congenital adrenal hyperplasia (CAH), little is known about the mechanism of this symptom. We set out to determine the relationship between menstrual pattern and biochemical characteristics of women with CAH due to 21‐hydroxylase deficiency.

Development and validation of a quantitative assay based on tandem mass spectrometry

Many routine hospital and clinical research assays have relied upon immunoassay procedures to achieve sensitive measurements of a range of important analytes. Some of the methods have been developed in-house but increasingly commercial kits and automated analysers have become commonplace. The accuracies of these methods are under question in health care. Mass spectrometry (MS) is potentially a more accurate technique with the ability to demonstrate specificity. An introduction of the basic analytical aspects of liquid chromatography (LC)–MS/MS leads on to the validation of the method before general use. LC coupled with MS and tandem mass spectrometry (MSn) is being adopted in a number of hospital laboratories for the quantitative analysis of a number of analytes from physiological matrices, but standards for development and validation of such assays are not easily available. Most assays can be regarded as in-house methods and herein may lay the failure so far for mass spectrometric methods to improve quality of results between laboratories for an analyte using the same technology. Manufacturers are taking on board the experience of clinical laboratories with kits containing all or most of the disposable items and reagents. A number of documents and guidelines have been consulted. These documents are expensive to purchase, are often very long and not easy to read. This review highlights the specific requirements for introduction of a tandem mass spectrometric test for small molecules into a routine hospital laboratory. A number of experiments need to be planned and executed in order to describe a new quantitative method in terms of selectivity, accuracy, imprecision, sensitivity and stability. The introduction of a quantitative method based on tandem MS requires careful validation. This review has distilled out important points from a number of key documents in order to provide a working validation guideline for clinical laboratories. In a supplementary file a working document for assembling the assay validation is proposed.

Diminished adrenal androgen secretion in familial glucocorticoid deficiency implicates a significant role for ACTH in the induction of adrenarche.

OBJECTIVE The mechanism of adrenarche is controversial, and there have been competing claims that its origin is in the hypothalamo‐pituitary axis or in the adrenal gland itself. ACTH is a proposed inducer of adrenarche so patients with ACTH resistance due to the familial glucocorticoid deficiency syndrome provide a model to clarify the degree to which ACTH is involved in the regulation of adrenal androgen secretion during adrenarche.

Genotype‐phenotype analysis in late onset 21‐hydroxylase deficiency in comparison to the classical forms

To establish the type and frequency of mutations causing late onset 21‐hydroxylase deficiency and associated clinical and biochemical phenotypes and to compare these findings to those from heterozygotes and homozygotes for classical 21‐hydroxylase deficiency.

Evaluation of Neonatal Screening for Congenital Adrenal Hyperplasia

Neonatal screening for congenital hypothyroidism has been effective in early detection and treatment of the condition. The position with respect to neonatal screening for congenital adrenal hyperplasia has been debated for many years. Some countries have performed congenital adrenal hyperplasia screening for many years, others have conducted pilot studies that were then not adopted. This article endeavours to summarize the complex issues behind decisions whether to screen or not and summarizes the findings of neonatal congenital adrenal hyperplasia screening programmes.

Unusual results from immunoassays and the role of the clinical endocrinologist

Endocrinology was revolutionized in the 1960s by the introduction of hormone measurements based on immunoassay and for quantitative analysis of proteins and peptides there are still few viable alternatives. Before that time the concentrations of hormones were determined by chemical and biological measures that varied in specificity, were tedious and often needed large samples of biological fluid or tissue to enable detection of the hormone. Immunoassays are based on recognition of molecules by antibodies. Polyclonal antibodies are raised in a number of animal species. Monoclonal antibodies in murine systems are widely used. As a label, radioactivity is often now substituted with a fluorescent, chemiluminescent tag or even an enzyme reaction. Not all assay systems depend upon separation of the antibody-bound elements. Immunoassay methods can show such high specificity and sensitivity that there is a sense of security in the value of laboratory results. There are, however, instances where a clinician finds that one or more results make no sense in terms of the patient presentation or overall clinical /endocrine picture. Clinicians must be alert to the fact that immunoassays do not always produce correct results and they will require some appreciation of where problems arise. A test request seeks to refute or confirm a clinical differential and any discrepancies in patient data should be reported to the laboratory so that appropriate investigations can be carried out. Unusual results are largely due to interferences from sample constituents (endogenous factors) and many such phenomena are recognized. These factors can be detected and eliminated, but they vary from patient to patient and also from time to time in one patient. 1 Results higher than real are recorded due to a lack of antibody specificity, although with changes in the formulation of some assays, particularly from manual techniques to highly automated procedures, negative effects can now also be encountered. Interferences caused by external factors are defined as exogenous factors and may be the result of pre-analytical factors, such as sample collection, but results can also be influenced by assay formulation. Rather than disregard any mismatch, there needs to be an explanation for these discrepancies in results to avoid further confusion about patient diagnosis and management and wasted resources over further tests that may be meaningless. Laboratories use numerous quality assurance schemes in their routine testing to identify systematic errors. For effect, these schemes need to be timely. The samples circulated can be selected to address specific analytical issues so as to test ability to identify erroneous results arising from aberrant patient samples. Clinicians can provide valuable materials for these quality exercises. When alerted to assay problems, the laboratory can take steps to derive accurate test results. Any form of interference may result in incorrect values being produced, upon which clinical decisions are made. Many such problems have been reported in the literature. Table 1 includes a number of examples. In some cases there have been medico-legal actions arising from the clinical judgements. Despres and Grant 25 reviewed the clinical consequences of failure to recognize interferences in thyroid assays. Clinicians need to be aware that analysers may not always provide the best measure of the most appropriate hormone. For instance, vitamin D2 therapy may not be detected with certain 25-hydroxy D assays. 26 Although the immunoassay has remarkable flexibility and sensitivity as an analytical tool, its reliability compared with other automated technologies used in biochemical analyses needs attention. 27

Carrier status for steroid 21‐hydroxylase deficiency is only one factor in the variable phenotype of acne

Previous endocrine studies of women with acne have produced diverse results. This study was designed to seek evidence, from endocrine and genetic studies, for impaired steroid biosynthesis in patients with acne.