Auditory brainstem response audiometry in congenitally hypothyroid children under early replacement therapy

Using auditory brainstem response audiometry, we evaluated 34 congenital hypothyroidism children under thyroid hormone therapy and 24 age- and sex-matched controls between 5 and 12 yr of age. Two main auditory brainstem response abnormalities were encountered: first, prolonged wave I latencies, secondary to a peripheral impairment, were found in seven congenital hypothyroidism children (20%): three of these showed signs of serious otitis media, unilaterally in two and bilaterally in the other, at the time of the evaluation. Second, shortened I-V interpeak latencies were observed in 10 children (29%). No correlation was found between the interpeak latencies and the L-thyroxine serum values at the time of the test or just prior to treatment initiation. Also, there was no correlation with estimated bone age at treatment initiation or with the Griffiths global mental development quotients assessed at 5 yr of age. These preliminary results suggest a significant incidence of auditory brainstem response abnormalities in treated hypothyroid children.

HLA system, body fat and fat distribution in children and adults

The association between the genotypes and the alleles at the A, B or C locus of the HLA system and body fat was studied in a total of 1578 individuals subdivided in four cohorts: adult males (n greater than or equal to 204), adult females (n greater than or equal to 184), boys and male adolescents (n greater than or equal to 282), and girls and female adolescents (n greater than or equal to 257). None of these subjects were grossly obese or had known metabolic disorders. Percent body fat from underwater weighing, subcutaneous fat from 6 skinfold measurements, trunk fat (3 skinfolds) and extremity fat (3 skinfolds) were considered in the analysis. Although a few significant associations were encountered, the lack of consistency across samples suggested that they were probably random and biologically not meaningful. The same negative findings were found for the ratio of trunk subcutaneous fat to extremity subcutaneous fat and the ratio of subcutaneous fat (6 skinfolds) to total fat mass. Earlier reports indicating a significant association between high body fat content and antigens B18, Bw35 or Cw4 were not supported by the results of this study. It was concluded that no consistent pattern of association emerged between genotypes or alleles of the HLA system and percent body fat, subcutaneous fat or fat distribution in children and adults of both sexes.

An analysis of the variation of incidence of congenital dysgenetic hypothyroidism in various countries

The seasonal and chronological distributions of birth dates of 820 patients with congenital hypothyroidism due to thyroid dysgenesis were analysed in eight areas in the world. The incidence had some seasonal variations in certain areas. These observations suggest that some environmental factors cause this disease.

Psoriatic arthritis: risk factors for patients with psoriasis - a study based on histocompatibility antigen frequencies

Histocompatibility antigen frequencies were studied in a group of 100 patients with psoriatic arthritis (PSA) and were compared to a group of 80 patients whose psoriasis was restricted to skin lesions (PSC). The antigens B13, BW57 (17), CW6 were significantly increased in PSC while BW57 (17), BW39, CW6 and CW7 were increased in PSA. No DR or MT antigen was elevated in frequency when compared to normal controls. The significant information which results from this study includes: 1) a failure to confirm previous reports on HLA-DR antigen increased frequencies; 2) an association, in this population, of BW39 with PSA and not BW38; 3) finding of a closer link of PSC and PSA with HLA-C rather than HLA-B antigens; 4) an estimate of relative risk for patients with PSC to develop PSA.

Higher sensitivity of primary thyrotropin in screening for congenital hypothyroidism: a myth?

We have simultaneously measured T4 and TSH concentrations from 93,000 consecutive filter paper blood samples received by the Quebec network for Genetic Medicine. T4 was measured using the Micromedic Automated System and TSH was measured by RIA kits from Pharmacia and Becton Dickinson, each for a 6-month period. Statistical analyses to assess quality control parameters for the various methods revealed that the T4 assay had greater precision and reproducibility than either of the 2 commercially available TSH kits. The number of false negative results was similar for both methods. Eight infants with ectopic thyroid glands were correctly detected by the T4 method. One infant with secondary hypothyroidism was detected by the T4 approach and missed by the TSH methodology. Three infants overall would have been missed using either the T4 or TSH approach. These data indicate that primary T4 screening has similar sensitivity compared to TSH kits for mass screening programs for congenital hypothyroidism.

Preliminary results on the mental development of hypothyroid infants detected by the Quebec Screening Program

A prospective study of the mental development of hypothyroid infants detected by the Quebec Network for Genetic Medicine began in January, 1976. The mean age at initiation of thyroid hormone therapy was 27 days. Forty-five hypothyroid infants and 37 normal control subjects were assessed at age 12 months with the Griffiths mental development test; 77 and 41, respectively, were assessed at age 18 months, and 59 and 40, respectively, at 36 months. There were no statistically significant differences in the various test scores between the two populations at age 12 months, but at age 18 and 36 months the hypothyroid infants had lower scores in hearing-speech performance scales and practical reasoning (36 months) which also decreased their global quotient. The mean scores were still above 100 and only nine were below 85. Further assessment of the influence of early therapy on mental development at age 6 years is needed before definitive statements can be made about the long-term mental development in these subjects.

Prevention of mental retardation in offspring of hyperphenylalaninemic mothers

Maternal hyperphenylalaninemia constitutes a potential hazard to the fetus for whom the risks of postnatal mental retardation, microcephaly, and congenital malformations are elevated. Preconception and intragestational dietary treatment can apparently improve the outcome of such pregnancies. In the absence of predictive mechanisms for pregnancies at risk and preventive measures involving reproductive counseling and treatment, there could be a rebound in the population frequency of mental retardation related to disorders of phenylalanine metabolism in subsequent generations. We describe a program serving a population of six million that includes screening, diagnosis, treatment, and counseling of the hyperphenylalaninemias. The program has recently added a simple dedicated register for males and females with hyperphenylalaninemia to supplement traditional methods for continuous surveillance of probands. We registered 153 patients: 43 females and 56 males with phenylketonuria, 23 females and 31 males with benign hyperphenylalaninemia, of which 22, 7, 27 and 5, respectively, had reached their 12th birthday in an 1981. Regional centers in the program provided counseling about the consequences of maternal hyperphenylalaninemia and the options to prevent them. No family has rejected the principle or fact of the Register and its goals.

Hearing loss among miners claiming compensation

Otological and audiological evaluations were performed on 278 miners claiming compensation for noise-induced hearing loss (NIHL). Of the total sample, 28.7% had to be excluded as cases of nonmining NIHL. Of the cases of diagnosed as NIHL, approximately 50% showed an actual hearing impairment as based on a low fence of 25 dB for the average hearing levels at 0.5, 1, and 2 kHz, and 63% as based on the average hearing levels at 0.5, 1, 2, and 3 kHz for exposures of 15 to 49 years. No significant difference in NIHL was apparent except at 2 kHz between subjects exposed to intermittent vs intermittent-continuous noise. It was difficult to differentiate NIHL from sensorineural losses of other causes and impossible to apply an adequate correction factor for presbycusis.

Thyroxine-binding globulin capacity and concentration evaluated from blood spots on filter-paper in a screening program for neonatal hypothyroidism

We describe a simple method for evaluating thyroxine-binding globulin capacity and concentration from a single 1-cm blood spot on filter-paper used in a screening program for neonatal hypothyroidism. This method permits prompt diagnosis of about 90% of the infants with thyroxine-binding globulin deficiency in our abnormal low-thyroxine, low-thyrotropin population. There was excellent equivalence between results obtained by our method and by the method of Chopra et al. (J. Clin. Endocrinol. Metab. 35:565, 1972), and minimal overlap between the population with low thyroxine-binding globulin and the low-thyroxine, normal thyrotropin population. We recommend this method to all programs in which a primary thyroxine measurement is used in screening for congenital hypothyroidism.

Thyroxine-binding globulin capacity and concentration evaluated from blood spots on filter-paper in a screening program for neonatal hypothyroidism

We describe a simple method for evaluating thyroxine-binding globulin capacity and concentration from a single 1-cm blood spot on filter-paper used in a screening program for neonatal hypothyroidism. This method permits prompt diagnosis of about 90% of the infants with thyroxine-binding globulin deficiency in our abnormal low-thyroxine, low-thyrotropin population. There was excellent equivalence between results obtained by our method and by the method of Chopra et al. (J. Clin. Endocrinol. Metab. 35:565, 1972), and minimal overlap between the population with low thyroxine-binding globulin and the low-thyroxine, normal thyrotropin population. We recommend this method to all programs in which a primary thyroxine measurement is used in screening for congenital hypothyroidism.

Thyroxine-binding globulin capacity and concentration evaluated from blood spots on filter-paper in a screening program for neonatal hypothyroidism

We describe a simple method for evaluating thyroxine-binding globulin capacity and concentration from a single 1-cm blood spot on filter-paper used in a screening program for neonatal hypothyroidism. This method permits prompt diagnosis of about 90% of the infants with thyroxine-binding globulin deficiency in our abnormal low-thyroxine, low-thyrotropin population. There was excellent equivalence between results obtained by our method and by the method of Chopra et al. (J. Clin. Endocrinol. Metab. 35:565, 1972), and minimal overlap between the population with low thyroxine-binding globulin and the low-thyroxine, normal thyrotropin population. We recommend this method to all programs in which a primary thyroxine measurement is used in screening for congenital hypothyroidism.

Blood thyroxine concentration is lower in low-birth-weight infants

From out data bank, we analyzed results for thyroxine concentration in blood samples spotted on filter paper from different age groups (one to nine days postpartum) of our low-birth-weight and normal population. It was significantly lower in the low-birth-weight infants in almost all the age groups, and in both groups it significantly declined after postnatal day 5. The influence of weight is more important in the low-birth-weight population, but does not completely explain the smaller values. The results indicate that blood samples used in screening for congenital hypothyroidism in the neonate should be taken on postnatal days 3 to 5, and if a recall specimen is collected on days 5 to 9, one should expect the thyroxine concentration in the second specimen to be lower than in the first.

Blood thyroxine concentration is lower in low-birth-weight infants

From out data bank, we analyzed results for thyroxine concentration in blood samples spotted on filter paper from different age groups (one to nine days postpartum) of our low-birth-weight and normal population. It was significantly lower in the low-birth-weight infants in almost all the age groups, and in both groups it significantly declined after postnatal day 5. The influence of weight is more important in the low-birth-weight population, but does not completely explain the smaller values. The results indicate that blood samples used in screening for congenital hypothyroidism in the neonate should be taken on postnatal days 3 to 5, and if a recall specimen is collected on days 5 to 9, one should expect the thyroxine concentration in the second specimen to be lower than in the first.

Polystyrene tube immunoradiometric assay for human alpha1-fetoprotein, and its use for mass screening

We describe a two-site immunoradiometric assay for human alpha1-fetoprotein, with use of antibody-coated polystyrene tubes as solid phase. The sensitivity, precision, and simplicity of this system make it eminently suitable for mass-screening purposes. We currently use it for neonatal detection of hereditary tyrosinemia in the Province of Quebec; measurements are made on blood spotted and dried on paper. This system could be well suited for other mass surveys, such as prenatal screenings for fetal abnormalities.

Polystyrene tube immunoradiometric assay for human alpha1-fetoprotein, and its use for mass screening

We describe a two-site immunoradiometric assay for human alpha1-fetoprotein, with use of antibody-coated polystyrene tubes as solid phase. The sensitivity, precision, and simplicity of this system make it eminently suitable for mass-screening purposes. We currently use it for neonatal detection of hereditary tyrosinemia in the Province of Quebec; measurements are made on blood spotted and dried on paper. This system could be well suited for other mass surveys, such as prenatal screenings for fetal abnormalities.

Modification of a screening program for neonatal hypothyroidism

From our experience in the screening of 212,000 newborn infants, we have devised a flow chart for processing T4 and TSH measurements obtained from initial filter paper blood spots. To date, all infants with thyroid dysfunction or TBG deficiency have been detected. Of the population screened, 1.84% require a spot TSH determination, and 1.1% require repeat determinations of T4.

The inbreeding coefficients of the Hadza

A systematic tabulation is provided of the frequency of different types of inbreeding in the Hadza. Genealogical information was obtained for 931 individuals, alive and dead. Inbreeding was encountered with 165 individuals. There were 49 different types of inbred genealogy. No attempt was made to calculate an average inbreeding coefficient and the reasons for this are given in the text.