Genetic counseling training and certification in Australasia.

The development of standards for training and certification is essential to the credibility and integrity of a developing profession. Training and certification of genetic counselors in Australasia has undergone a detailed review during the past few years, resulting in changes to the way certification is obtained. This paper presents an overview of the process of developing a robust training and certification program which reflects the social and cultural environment of genetic counselors working in Australasia. A brief history of the development of the profession in Australasia is provided, followed by a detailed discussion of the recent development of Masters programs and a portfolio of work required for certification. The importance of consultation within the profession and with our colleagues in the field of human genetics is considered, and we provide a discussion of defining moments that occurred during the review. This paper is intended to provide a detailed description of genetic counselor training and certification in Australasia. We anticipate that our insights into the process of redevelopment of training and certification guidelines may be helpful for genetic counselors working in countries where certification requirements are being developed.

Developmental variation in copper, zinc and metallothionein mRNA in brindled mutant and nutritionally copper deficient mice.

The concentrations of copper, zinc and metallothionein-I (MT-I) mRNA were determined in the liver, kidney and brain of the brindled mutant mouse from birth until the time of death. Despite accumulation of copper in the kidney of the mutant, MT-I mRNA concentrations were normal. There was no difference between the MT-I mRNA in the brain of mutant and normal in the first 10 days of life, but after day 10 metallothionein mRNA levels were increased in the mutant. The concentration of copper was very low in the liver of the mutant, and on day 6 after birth the metallothionein mRNA was also reduced by about 50%. This reduction was not seen in copper-deficient 6-day-old pups, despite very low hepatic copper levels. This suggests that the lower hepatic MT-I mRNA in the day 6 brindled mouse was not simply due to the reduction in hepatic copper and also that hepatic copper is not regulating metallothionein gene expression the liver of neonatal mice. After day 12 hepatic MT-I mRNA levels were elevated in mutant and in copper deficient mice, both of which die at 14 to 16 days. These increases and the increase in brain MT-I mRNA in older mutant mice are likely to be caused by stress. Overall the results support the conclusions that the brindled mutation does not cause a constitutive activation of the metallothionein genes, and that the differences in metallothionein mRNA between mutant and normal are most probably secondary consequences of the mutation.

Effects of exercise training and dietary manipulation on insulin-regulatable glucose-transporter mRNA in rat muscle.

Both exercise training and dietary manipulation (increasing omega-3/omega-6 fat ratio) can ameliorate insulin resistance caused by a high-fat diet in rats. We determined whether alterations in the expression of the insulin-regulatable (IR) and/or HepG2 glucose-transporter (GT) mRNAs were similarly affected. There was a significantly higher level of IRGT mRNA in skeletal muscle from exercise-trained versus sedentary high-fat-fed rats (27% increase, P less than 0.01). This difference is consistent with previously reported increases in muscle insulin-mediated glucose uptake. Skeletal muscle HepG2GT mRNA was too low to detect any training effect, but there was a tendency toward higher levels with training in cardiac muscle. In contrast, dietary manipulation, previously shown to lead to a much greater increase (100-300%) in muscle insulin-mediated glucose uptake, did not change IRGT or HepG2GT mRNA in skeletal muscle or heart. Thus, both dietary manipulation and exercise training increase insulin-stimulated glucose uptake in skeletal muscle, but only exercise training increases IRGT mRNA. Therefore, exercise training apparently increases GT production, whereas dietary manipulation improves glucose transport in skeletal muscle by other mechanisms.

Prevalence of fragile X syndrome.

The much-quoted prevalence figure of 1:1,000 males for fragile X syndrome is an overestimate in a mixed ethnic population. A reexamination of the individuals from whom those data were derived using molecular diagnostic techniques demonstrates a more realistic figure of 1:4,000 males.

Informed choice in fragile X syndrome and its effects on prevalence.

We present the effect of case finding, cascade testing, and counselling for fragile X syndrome in a population of 6.5 million over a decade. Carrier females made informed choices that resulted in a 10-fold decrease in the prevalence of affected males in their offspring.

Dissemination of genetic risk information to relatives in the fragile X syndrome: guidelines for genetic counselors.

Fragile X Syndrome, which affects 1 in 1,250 males, is the most common inherited condition causing mental retardation. Although carrier detection for the fragile X syndrome utilizing DNA has now been simplified, genetic counseling and the process of informing at-risk family members remains complex. The purpose of this paper is to offer practical guidelines to health professionals providing genetic counseling to fragile X families in order to facilitate the dissemination of genetic risk information to relatives. This paper was developed from a workshop held at the 4th International Fragile X Conference. The guidelines presented here represent a beginning in the development of an approach to informing relatives in fragile X families about genetic risk, and the identification of mechanisms to reduce the burden to families.

Counselling risk figures for fragile X carrier females of varying band sizes for use in predicting the likelihood of retardation in their offspring.

We have derived risk figures for fra(X) syndrome carrier mothers based on their DNA status. Clinical and molecular information was analysed in 200 carrier mothers and their offspring. Individuals were classified as affected by a requirement for special education. Risk figures were calculated using the genotype of the intellectually normal offspring in order to reduce ascertainment bias. Analysis was made on women with differing mutation size to predict the proportion of affected offspring. Using this method the following risk figures were derived: 1. For carrier women with an increase (delta) of 0.06-0.14 Kb, the risk for having an affected son was 29% (1 in 3.5) and 25% for daughters (1 in 4). This predicts an overall 73% chance of a normal child. 2. For delta size 0.15-0.24 Kb, the risk of having an affected son was 46% (1 in 2.2) and 32% for daughters (1 in 3.1), predicting a 61% chance of a normal child. 3. For delta size > 0.24 Kb, normal transmitting male offspring were not seen, i.e., the risk for males was 50% (1 in 2) and for females 32% (1 in 3.1) which predicts a 59% chance of a normal child.

Comparison of cell culture with an amplified enzyme immunoassay for diagnosing genital herpes simplex infection.

An amplified enzyme immunoassay (EIA) for herpes simplex virus (Novo Nordisk) was compared with cell culture in 853 genital specimens from a genito-urinary medicine clinic. The sensitivity of the EIA was 86% and its specificity 99.6%. The sensitivity increased to 94% for lesion swabs but decreased to 68% for cervical swabs. Sensitivity for urethral and vulval swabs was 83% and 82%, respectively. It is concluded that the EIA is specific and quick and easy to perform. It will be suitable for testing for genital herpes simplex infections in laboratories without access to local cell culture facilities.

Cigarette smoking and the microbial flora of the mouth.

A range of selective media was used to culture the microbial flora of the dental plaque, tongue and palate, The subjects were five young men who smoked more than twenty cigarettes a day and four who did not smoke. Neisseriae were less numerous on the mucosal surfaces of the smokers.

An evaluation of a shared experience group for women and their support persons following prenatal diagnosis and termination for a fetal abnormality.

OBJECTIVES: Support after fetal diagnosis of abnormality (SAFDA), is a facilitated shared experience group for women and their partners or support person, in Victoria, Australia, who have had a pregnancy termination for a fetal abnormality. The objective of this study was to evaluate the SAFDA-facilitated group. METHODS: A questionnaire-based study was undertaken between 2001 and 2005 to evaluate SAFDA. A deidentified self-completed questionnaire was given to participants at the end of each group and included questions relating to the referring professional, participants' prior expectations of the group, helpfulness of participation, preferred group format, length, and venue. In addition, there was also opportunity for participants to make general comments on their experiences of participating in SAFDA. RESULTS: A total of 85 participants (100% response) completed the questionnaire. Seventy-one participants (84%) considered it 'very helpful' to participate in the group. Seventy-eight participants (92%) considered that a shared-experience group was the most beneficial format. Comments written by participants affirmed that the present format of SAFDA was a highly valued opportunity to listen to and share experiences in a confidential small group. CONCLUSION: SAFDA is a beneficial forum for women and their partners or support person to share their experiences after having had a pregnancy termination for a fetal abnormality. Further, SAFDA provides information and insights for health professionals who are considering how best to support women.

An analysis of the rate of metallothionein mRNA poly(A)-shortening using RNA blot hybridization.

A progressive reduction in the size of rat metallothionein-1 mRNA following induction by copper chloride or dexamethasone was demonstrated on RNA blots, and was shown to be due to shortening of the poly(A)-tail. The rate of poly(A) removal was the same in rat liver and kidney following copper chloride induction, in rat liver following dexamethasone induction, and in mouse liver following copper chloride induction. In mouse liver metallothionein-1 and 2 mRNAs were shortened at the same rate. The reduction of the poly(A) tail was more rapid in the first 5 hours (approximately 20 nucleotides/h) but much slower (approximately 3 nucleotides/h) after the poly(A)-tail had been reduced to about 60 residues. Metallothionein mRNA molecules with poly(A) tail sizes less than 30-40 nucleotides were not observed. Exonuclease digestion of the poly(A)-tail is suggested, at least in the initial rapid phase. It is hypothesized that poly(A)-tails longer than 30 are required for mRNA stability and that much longer poly(A) tails may give newly synthesized mRNA molecules a competitive advantage in protein synthesis.

Induction of metallothionein mRNA in rat liver and kidney after copper chloride injection.

The kinetics of the increase of metallothionein mRNA in rat liver and kidney after CuCl2 injection was determined by cell-free translation and dot-blot hybridization of total RNA isolated at various times after the injection. Both assay procedures gave essentially the same result: a 16-fold increase in hepatic metallothionein mRNA was observed 7h after CuCl2 injection, with a decline to basal values by 15 h. The response in the kidney was less dramatic, with a 6-fold increase in metallothionein mRNA 5 h after injection, and basal values were attained by 12h. The rise in Cu2+ concentration in both organs was closely correlated with the increase in metallothionein mRNA; hepatic Cu2+ was increased 5.9-fold by 5h after injection and renal Cu2+ was increased 4.3-fold 5h after injection. The Zn2+ concentration in the liver had not risen significantly within 5h of Cu2+ injection. Renal Zn2+ concentrations did not alter appreciably in the Cu2+-treated animals. These results support the conclusion that Cu2+ is acting as a primary inducer of metallothionein mRNA in the rat.

The primary structure of the imported mitochondrial protein, ornithine transcarbamylase from rat liver: mRNA levels during ontogeny.

Ornithine transcarbamylase, one of the enzymes of the urea cycle in ureotelic organisms, is synthesized in the cytoplasm of hepatocytes as a precursor larger than the mature form found in the mitochondrial matrix. We deduced the amino acid sequence of the precursor of ornithine transcarbamylase from rat liver from the nucleotide sequence of overlapping cDNA clones spanning the complete coding region, 3' untranslated region, and most of the 5' untranslated region of the mRNA. The mature enzyme consists of 322 amino acids and is derived from the larger precursor by proteolytic removal of 32 amino acids from the amino-terminus. The amino-terminal extension contains eight basic and no acidic residues. This highly basic character appears to be a feature of presequences on cytoplasmically synthesized mitochondrial proteins. Comparison of the amino acid sequence determined for the enzyme from rat with that from human liver (Horwich et al., 1984) shows that there is a high degree of homology between the sequences of the mature protein (93%) and relatively less homology between the sequences of the amino-terminal extension (72%). The ornithine transcarbamylase from rat liver also shows a considerable degree of amino acid homology (44%) with the enzyme from Escherichia coli (Van Vliet et al., 1984) and leads to suggestions about residues involved in substrate binding and catalysis. An analysis of levels of RNA in fetal and neonatal liver shows that ornithine transcarbamylase mRNA levels increase from about 40% of adult levels at day 14 of gestation to a peak at day 20 of gestation, and, after a drop around the time of birth, rises to adult levels during the second week after birth.

Analysis of DNA probes for the prenatal diagnosis of cystic fibrosis.

Cystic fibrosis is a common autosomal recessive disease in white persons. Prenatal diagnosis by DNA analysis became possible in families with a child who is affected by cystic fibrosis when the probes pJ3.11, metH and metD, which are linked closely to the cystic fibrosis gene (CF) were described. The recent description of the XV-2c and KM.19 probes has improved the prenatal diagnosis of cystic fibrosis greatly. The KM.19 probe alone was informative in eight of 12 families that were studied while XV-2c was informative in eight of 12 families that were studied while XV-2c was informative in only two of the 12 families. In contrast, the use of the pJ3.11, metH and metD probes in combination allowed full diagnosis in six of the 12 families. The combined use of the CF-linked probes produced informative data for all 12 families. Therefore, in most families with at least one affected living child, the first-trimester diagnosis of cystic fibrosis is possible with fetal DNA that has been prepared from chorionic villous samples. Strong linkage disequilibrium was found with both the KM.19-PstI polymorphism and the XV-2c-TaqI polymorphism and the CF gene.

The use of restriction fragment length polymorphisms in prenatal diagnosis of dihydropteridine reductase deficiency.

Using a human dihydropteridine reductase (hDHPR) cDNA probe we have detected two AvaII and one MspI restriction fragment length polymorphisms (RFLPs). We show that these RFLPs are in disequilibrium and calculate that approximately 60% of Caucasians are heterozygous for at least one RFLP. We demonstrate the usefulness of these RFLPs in prenatal diagnosis of DHPR deficiency in one family. This disorder can also be predicted by enzyme assays and we therefore discuss the relative merits of the two methods of prenatal diagnosis.

A study of the role of metallothionein in the inherited copper toxicosis of dogs.

The role of metallothionein (MT) was assessed in the copper-loading disease prevalent in Bedlington terriers. Fractionation of tissue supernatants over Sephadex G-75 showed that most of the additional cytosolic copper present in liver tissue of these dogs was bound to MT, and that substantially more MT-bound copper could be solubilized by detergent plus mercaptoethanol. Zinc contents were only slightly raised, although most of the extra zinc was associated with a 4000-Mr ligand. Ion-exchange chromatography revealed two isoproteins, MT1 and MT2, in all the dog liver samples examined. In Bedlington terrier liver, copper associated with both isoproteins was increased, although the increase for MT2 was greater than for MT1. The content of MT protein was also raised, although cell-free translations and RNA blots of total liver RNA showed that this increase was not associated with a rise in MT mRNA. The significance of these results to the mechanism of copper accumulation in the Bedlington terrier disorder is discussed.

Human dihydropteridine reductase: characterisation of a cDNA clone and its use in analysis of patients with dihydropteridine reductase deficiency.

Deficiency of human dihydropteridine reductase (hDHPR) causes malignant hyperphenylalaninemia. We report the isolation of a cDNA clone for hDHPR that spans the complete coding region, and present the nucleotide sequence and the predicted amino acid sequence. The hDHPR protein does not share extensive homology with the enzymatically related protein human dihydrofolate reductase. Patients with hDHPR deficiency were analysed for the presence of hDHPR cross-reacting protein, mRNA encoding hDHPR, and chromosomal DNA rearrangements. The results show that this inherited error of metabolism can result from a variety of mutations. However, no major rearrangements were seen in 11 patients analysed by Southern blotting. Three RFLPs were found with the restriction endonucleases AvaII and MspI. These RFLPs are useful for prenatal diagnosis of hDHPR deficiency.