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PubMed2001

Longitudinal growth, sexual maturation and final height in patients with congenital hypothyroidism detected by neonatal screening.

OBJECTIVE: To evaluate longitudinal growth, pubertal development and final height in patients with congenital hypothyroidism (CH) detected by a neonatal screening programme, and to identify factors potentially affecting growth outcome. PATIENTS: Fifty-five patients (41 females) detected by neonatal screening and followed longitudinally from the time of diagnosis and treatment (25+/-5 days) up to the age of 17+/-0.5 years were evaluated retrospectively. RESULTS: Pubertal development began and progressed normally in both males and females. In boys, a testicular volume of 4 ml was reached at 11.3+/-1.0 years. In girls breast enlargement (B2) occurred at a mean age of 10.3+/-1.2 years and the mean age of menarche was 12.5+/-1.2 years. The onset and the progression of puberty were independent of the aetiology, the severity of CH and the timing of the beginning of treatment. Girls treated with an initial amount of L-thyroxine (L-T4) greater than 8 microg/kg per day showed an earlier onset of puberty (B2 9.4+/-0.9 years; menarche 11.5+/-0.8 years) compared with girls treated with a lower initial dose of L-T4 (B2 10.5+/-1.2 years; menarche 12.6+/-1.2 years; P<0.02). However, both groups attained a similar final height (-0.1+/-1.0 SDS and 0.4+/-1.0 SDS, respectively), which in both cases was above the target height (P=0.03). All the patients in the study attained a mean final height (0.1+/-1.1 SDS) within the normal range for the reference population and above the target height (-0.9+/-0.9 SDS, P<0.0001). No significant relationship was found between final height and severity of CH at diagnosis, initial L-T4 dosage or aetiology of the defect. Patients with ectopic gland, thyroid aplasia or in situ gland attained a similar mean final height (0.1+/-1.1 SDS, 0.5+/-1.0 SDS and -0.5+/-1.0 SDS, respectively), which was in all cases greater than target height (-1.0+/-0.9, -0.6+/-0.8, -0.9+/-0.8 respectively; P<0.05). CONCLUSIONS: Our results suggest that conventional management of children with CH detected by neonatal screening leads to normal sexual development and normal adult height, and that the major factor determining height in these children is familial genetic growth potential.

Body Height↗

PubMed2004

Neonatal screening for glucose-6-phosphate dehydrogenase deficiency fails to detect heterozygote females.

We examined glucose-6-phosphate dehydrogenase (G6PD) deficiency in north-eastern Italian Caucasian neonates detected by neonatal screening, in order to measure the incidence of heterozygote females detected by neonatal screening, and to estimate the near-true total incidence. A total of 85,437 Caucasian neonates, born between January 2000 and December 2001, have been enclosed in the study. The total incidence of the disease, measured by fluorescent method, is 0.9 per thousand; the total incidence, calculated by Hardy-Weinberg law, is 4.8 per thousand. The frequency of missed females is 93% of total females expected with G6PD deficiency; most of them are very likely heterozygous females. The sensitivity of the fluorescent method might be not sufficient to detect all females. Since heterozygote females might develop the symptoms of G6PD deficiency later, these results suggest that the G6PD neonatal screening may not be helpful in preventing disease in females.

Female↗

PubMed2001

Neonatal screening for congenital adrenal hyperplasia: 17-hydroxyprogesterone levels and CYP21 genotypes in preterm infants.

OBJECTIVE: Neonatal screening for congenital adrenal hyperplasia (CAH) among preterm infants is complicated by the fact that healthy preterm infants have higher levels of 17-hydroxyprogesterone (17-OHP) than term infants, resulting in a higher false-positive rate. Even when gestational age-related cutoff levels after ether extraction were used, the false-positive cases primarily comprised preterm infants. The aim of the study was to optimize the procedure for neonatal screening for CAH in preterm infants. METHODS: The 17-OHP levels in 6200 preterm infants were correlated to the gestational age. We also calculated the number of recalls for different putative cutoff levels of the 17-OHP by direct assay and after extraction in 1275 preterm infants who represented the most elevated cases in a population of approximately 30 000 preterm infants. The CYP21 genotypes and screening levels were determined in the 12 preterm infants with CAH diagnosed since the start of screening. The effect of possible interfering factors such as gestational age, neonatal stress, and prenatal glucocorticoid treatment for pulmonary maturation was studied. RESULTS: The extraction procedure did not significantly improve the sensitivity or specificity of the screening, whereas it delayed the day of recall from 8 to 13 days (median). We could not demonstrate any systematic influence of the studied stress factors or the prenatal glucocorticoid treatment on the 17-OHP screening levels. In the patients with CAH, the 17-OHP levels correlated better with disease severity than with the degree of prematurity. CONCLUSIONS: On the basis of these results, we omitted the extraction step and changed the cutoff levels in the Swedish screening program for preterm infants. We chose to use a cutoff level of 400 nmol/L plasma in infants who were born before week 35 and 150 nmol/L for infants who were born in weeks 35 and 36. For detecting more patients, the cutoff level would have to be much lower, which would result in a number of false-positive tests that we consider to be unacceptably high. It is clear that neonatal screening cannot detect all infants with CAH. Some milder forms of the disease, just like in the past, will have to be diagnosed on the basis of clinical signs and symptoms.

17-alpha-Hydroxyprogesterone↗

PubMed1992

Congenital hydrocephalus secondary to Walker-Warburg syndrome identified on the Manitoba Neonatal Screening Programme for Duchenne muscular dystrophy.

This report describes our first experience with a clinically important true false positive neonatal screening test for Duchenne muscular dystrophy (DMD). Neonatal screening for DMD began as a pilot programme in Manitoba on 1 January 1986 by analysis of creatine kinase (CK) activity in dried filter paper blood spots. To date, all except two males with positive initial and follow up neonatal CK screening tests were subsequently diagnosed as having DMD. Of these two, one was a newborn male with congenital hydrocephalus whose positive DMD screening test led to the identification of an associated congenital myopathy and confirmation of the diagnosis of Walker-Warburg syndrome.

Biopsy↗

PubMed1986

Influence on psychological development of early treatment of congenital hypothyroidism detected by neonatal screening: a controlled study.

It has been shown that early diagnosis and treatment of congenital hypothyroidism based on neonatal screening will improve outcome. To test this hypothesis, we performed standard psychological tests (Gesell, Stanford-Binet, or Wechsler) in three groups of children with treated hypothyroidism: 14 were discovered by neonatal screening and 24 (15 with thyroid agenesis and 9 with ectopic thyroid) were diagnosed prior to institution of screening. Age (weeks) at initial treatment differed among the three groups (mean values +/- SE: screened 4.6 +/- 0.8, thyroid agenesis 19.3 +/- 4.0, ectopic thyroid 46.4 +/- 8.0). Age at testing averaged 3.3 years in all three groups. The global developmental quotient (DQ) or IQ score was lowest in the thyroid agenesis group (82 +/- 6, range 52 to 142), intermediate in the ectopic thyroid group (93 +/- 10, range 56 to 141) and highest in the screening group (104 +/- 4, range 75 to 127). Neonatal screening for congenital hypothyroidism results in earlier diagnosis than does use of the clinical criteria, and the consequent early treatment results in improved psychomental development.

Child Development↗

PubMed1995

Long term prognosis of patients with cystic fibrosis in relation to early detection by neonatal screening and treatment in a cystic fibrosis centre.

BACKGROUND: A study was undertaken to evaluate whether an early diagnosis by neonatal screening may improve the long term prognosis of patients with cystic fibrosis and to assess the influence of expert management started immediately after the diagnosis. METHODS: Comparative clinical follow up in three birth cohorts of patients with cystic fibrosis was performed at the Cystic Fibrosis centre in Groningen in close collaboration with paediatricians in general hospitals in the north-eastern part of the Netherlands. The first birth cohort (n = 19) was detected by screening and the two other cohorts were detected clinically, one (n = 30) consisting of patients born during the screening programme and the other (n = 32) of patients born during the six years immediately after the screening programme ended. The total number of patients in the three birth cohorts included all patients with cystic fibrosis born in this area during a 12 year period. Cumulative survival rates and the variation with time of lung function, the levels of immunoglobulins, and growth patterns were used as main outcome measures. RESULTS: Patients born during the screening programme but detected clinically appeared to have a reduced life expectancy compared with patients detected by screening. The patients detected by screening showed less deterioration in lung function (annual decrease 1.2% of FEV1 % pred), a smaller increase in immunoglobulin levels, and minimal catch-up growth compared with an annual decrease of 3.25% of FEV1 % pred in the non-screened birth cohort of the same age, a higher rise in immunoglobulins leading to increased levels at the end of the observation period, and catch-up growth for weight as well as height. Differences between patients treated in a cystic fibrosis centre and those not referred to a specialist centre were smaller but similar, in favour of treatment at a cystic fibrosis clinic. CONCLUSIONS: Expert management started immediately after an early diagnosis of cystic fibrosis by neonatal screening results in important beneficial effects on the outcome and clinical course of the condition. The institution of very early treatment may be critical for the outcome and long term prognosis for most patients with cystic fibrosis. Neonatal screening programmes for cystic fibrosis should be introduced more widely.

Age Factors↗

PubMedDate not supplied

[Neonatal screening for hereditary metabolic diseases. Nursing action].

The authors provide the information necessary so that nurses are capable of adequately carrying out the duties which pertain to neonatal screening programs for hereditary metabolic diseases. The authors briefly describe those diseases which are subject to neonatal screening with the objective of providing their basic features, especially in relation to neonatal screening and the benefits which this may provide. The authors explain the method to correctly take a blood sample on the paper filter sample cards and they describe the most frequently committed errors as a way to prepare nursing personnel which may at some time have contact with these functions so that these are properly performed.

Humans↗

PubMed2003

Final height and pubertal growth in Japanese patients with congenital hypothyroidism detected by neonatal screening.

AIM: To investigate the final adult heights and pubertal growth patterns in Japanese patients with congenital hypothyroidism (CH) detected by neonatal screening. METHODS: A retrospective chart review was conducted of female patients >15 y of age (n = 18) and male patients >18 y of age (n = 9), who were detected by neonatal screening and kept on continuous thyroid hormone replacement therapy. Final height standard deviation scores (FHSDS) and target height standard deviation scores (THSDS) were determined. Parameters characterizing the pubertal growth process (such as age at onset of pubertal growth spurt and age at peak pubertal growth) were obtained from each patient's growth rate chart. Menarchial age was determined in each female patient by reviewing the medical record. The impact on FHSDS of the etiology of CH, the severity of CH, the time of initiation of therapy and the adequacy of treatment during the first year of life was assessed. RESULTS: All patients had received initial thyroid hormone treatment no later than 50 d of age, and had reached their final height. The mean FHSDS for female and male patients were +0.17 +/- 0.99 and -0.03 +/- 0.99, respectively. The mean FHSDS-THSDS for female and male patients was +0.09 +/- 0.77 and -0.19 +/- 0.53, respectively. No difference was seen in pubertal growth parameters for either gender compared with that of the reference population, except for a greater peak height velocity and pubertal height gain in male patients. The mean menarchial age was identical to that of the reference population. No significant relationship was found between the FHSDS and any of the factors investigated. CONCLUSION: The adult height of patients with CH detected by neonatal screening was equivalent to that of the reference population and their target height. As long as early intervention and satisfactory management are ensured, severe CH does not appear to reduce final adult height.

Adolescent↗

PubMed1994

Neonatal screening for cystic fibrosis using immunoreactive trypsinogen and direct gene analysis: four years' experience.

OBJECTIVE: To assess the performance and impact of a two tier neonatal screening programme for cystic fibrosis based on an initial estimation of immunoreactive trypsinogen followed by direct gene analysis. DESIGN: Four year prospective study of two tier screening strategy. First tier: immunoreactive trypsinogen measured in dried blood spot samples from neonates aged 3-5 days. Second tier: direct gene analysis of cystic fibrosis mutations (delta F508, delta I506, G551D, G542X, and R553X) in samples with immunoreactive trypsinogen concentrations in highest 1% and in all neonates with meconium ileus or family history of cystic fibrosis. SETTING: South Australian Neonatal Screening Programme, Adelaide. SUBJECTS: All 88,752 neonates born in South Australia between December 1989 and December 1993. INTERVENTIONS: Neonates with two identifiable mutations were referred directly for clinical assessment and confirmatory sweat test; infants with only one identifiable mutation were recalled for sweat test at age 3-4 weeks. Parents of neonates identified as carriers of cystic fibrosis mutation were counselled and offered genetic testing. MAIN OUTCOME MEASURES: Identification of all children with cystic fibrosis in the screened population. RESULTS: Of 1004 (1.13%) neonates with immunoreactive trypsinogen > or = 99th centile, 912 (90.8%) had no identifiable mutation. 23 neonates were homozygotes or compound heterozygotes; 69 carried one identifiable mutation, of whom six had positive sweat tests. Median age at clinical assessment for the 29 neonates with cystic fibrosis was 3 weeks; six had meconium ileus and two had affected siblings. 63 neonates were identified as carriers of a cystic fibrosis mutation. Extra laboratory costs for measuring immunoreactive trypsinogen and direct gene analysis were $A1.50 per neonate screened. CONCLUSION: This strategy results in early and accurate diagnosis of cystic fibrosis and performs better than screening strategies based on immunoreactive trypsinogen measurement alone.

Cystic Fibrosis↗

PubMed2002

Epidemiology and survival analysis of cystic fibrosis in an area of intense neonatal screening over 30 years.

This population-based study was conducted in Veneto and Trentino (northwestern Italy, population 5 million). In this area, neonatal screening for cystic fibrosis started in 1973 and has been virtually universal since the early 1980s. During this study, the estimated incidence of cystic fibrosis in this region was 1/2,650 livebirths per year. The authors analyzed data on 593 patients born in 1938-2000 and living in the region who were followed by a single referral center. Median time from birth to confirmation of diagnosis after screening was 32 days (range, 0-1,531). For patients whose disease was recognized after symptoms occurred, median age at diagnosis was always less than 1 year. Median survival age was 37.7 years. Long-term survival (to age 20-30 years) was not significantly influenced by mode of diagnosis (screened or unscreened), sex, or age at diagnosis for unscreened patients (<1, 1-5, >5 years). Current survival analysis of three consecutive decades showed that improving survival tended to vanish in the last years of the study. The authors concluded that a regional neonatal screening program allows very early recognition of cystic fibrosis. They could not conclude that neonatal screening improves long-term survival if compared with diagnosis by symptoms in early infancy.

Age Distribution↗

PubMed2001

Intellectual outcome of patients with congenital hypothyroidism detected by neonatal screening.

BACKGROUND AND PURPOSE: Mental retardation is a major sequela of delayed treatment for congenital hypothyroidism; congenital hypothyroidism can be treated early if detected with neonatal screening. We evaluated the intellectual outcomes of 62 patients with congenital hypothyroidism detected by neonatal screening at a major teaching hospital in northern Taiwan. The effects of thyroid pathology, age at the initiation of treatment, socioeconomic status, and severity of hypothyroidism on intellectual outcome were also analyzed. METHODS: All patients had euthyroid status at the time of intelligence testing. The Chinese Fourth Revision of the Binet-Simon Scales was used to evaluate the patients' intelligence between the ages of 3 and 6 years. RESULTS: The mean intelligence quotient (IQ) score was 102 +/- 18. Only four of the 62 patients were mentally retarded. Patients with lower initial serum thyroxine concentrations (T4; < 2 micrograms/dL) at the time of diagnosis of congenital hypothyroidism had significantly lower IQs (95 +/- 19, n = 26) than those with higher initial T4 concentrations (106 +/- 16, n = 36; p < 0.05). Patients with fewer than three ossification centers had lower IQs (91 +/- 20, n = 12) than those with three or more (104 +/- 17, n = 36; p < 0.05). Significantly lower IQs were also found in patients with a smaller femoral epiphysis area (< 0.1 cm2) (92 +/- 20, n = 15) than in those with larger epiphyses (106 +/- 15, n = 21; p < 0.05). The type of pathology (ectopia, athyrosis, dyshormonogenesis), age at the start of treatment (before or after 30 days of age), and socioeconomic status did not significantly affect the intellectual outcome. CONCLUSIONS: Our results indicate that intellectual outcome in Taiwanese patients with congenital hypothyroidism has been improved by neonatal screening and that the severity of hypothyroidism at diagnosis is the most important prognostic factor affecting intellectual outcome in these patients.

Age Factors↗

PubMed2000

False positives in universal neonatal screening for permanent childhood hearing impairment.

High rates of false-positive neonatal screens for permanent childhood hearing impairment (PCHI) associated with raised hearing thresholds lead to unnecessary assessments of the baby, which may worry parents. False-positive rates need to be reduced, especially in view of the UK government's announcement that national neonatal screening will be introduced. We report screening criteria that give a six-fold reduction in false-positive rates.

Deafness↗

PubMed2005

False-positive results in neonatal screening for cystic fibrosis based on a three-stage protocol (IRT/DNA/IRT): Should we adjust IRT cut-off to ethnic origin?

Since 1979, newborn screening for cystic fibrosis (CF) has been possible by measuring immunoreactive tryspinogen (IRT) in blood spots. In France, a programme based on a three-stage strategy (IRT/DNA/IRT) started in 2002. In the Rhône-Alpes area, the positive screening rate (i.e. the proportion of samples sent for genotyping) observed after the first IRT measurement was higher than the expected rate (0.65% versus 0.50%), without a greater CF incidence. We hypothesized that the IRT reference range could differ according to the ethnic origin of the newborns. 35 141 newborns were studied and divided into two groups: European ethnic group 26 324 (75%) and North African ethnic group 8817 (25%). 243 positive newborns were identified: 146 (60%) in the European ethnic group and 97 (40%) in the North African ethnic group. Three CF patients and 11 unaffected heterozygotes were found in the European group, but no mutations were found in the North African group. Mean IRT values and the percentage of IRT values over the cut-off were significantly higher in the North African group than in the European group (mean IRT = 21.17 microg/L and 19.74 microg/L, p < 0.0001; %IRT > cut-off = 1.1% and 0.5%, respectively). For the positive screened newborns, term and IRT mean were comparable, whereas birth weight was higher in the North African ethnic group. These results lead us to conclude that (i) newborns from families of North African origin have higher IRT values and (ii) most of the positive screened newborns in this population could be considered as 'false positives'. These conclusions could explain, in part, the large variations seen in the positive screening rate in the French CF neonatal screening and raise the question whether it is relevant to adapt cut-off to ethnic origin of the newborns.

Africa, Northern↗

PubMed1981

Histidinaemia in Sweden. Report on a neonatal screening programme.

Histidinaemia screening was included in the epidemiological survey of the Swedish neonatal screening programme, 1971-72. Dried blood samples on filter paper collected neonatally from 171,000 infants were analysed the Guthrie method. A blood histidine level above 0.96 mmol/1 (15 mg per 100 ml) was regarded as a positive test and was found in 639 infants - i.e., 1/270. No further diagnostic measures were taken until 1977 when stored dried blood samples from 273 infants with a positive screening test were analysed for urocanic acid. Four children had undetectable blood urocanic acid. They were studied and histidinaemia was confirmed in two children, and excluded in two. Both histidinaemia children had normal psychomotor development at 7 years of age, in spite of the fact that no dietary treatment was given. The incidence of histidinaemia in Sweden was estimated as 1/37,00, on the basis of neonatal screening. In addition, histidinaemia was diagnosed in four individuals who were not detected in the neonatal screening programme; of these, only one had an IQ less than 85. At present, general neonatal screening histidinaemia in Sweden does not seem justified.

Adolescent↗

PubMed1981

Neonatal screening for hypothyroidism in Scotland: results of a pilot study.

We have assessed the feasibility of screening for neonatal hypothyroidism based on thyroxine (T4) or thyrotrophin (TSH) assays on dried blood spots collected for the phenylketonuria (PKU) screening programme in Scotland. The TSH assay was both more sensitive and specific than T4 in detecting primary hypothyroidism and was sufficiently rugged and rapid for routine application. Using a labelled antibody assay for TSH, 99.7 per cent of the first 30,000 babies tested had values less than 25 mU/l, and 0.24 per cent had values between 25 and 50 mU/l. Of the 11 suspected positives (TSH greater than 50 mU/l), nine were confirmed on serum specimens as primary hypothyroidism (prevalence 1:3,300) and the two false positives (0.007% of total) were explicable by inappropriate time of sampling. No false negatives have so far been identified. The median time to detection by blood spot assay was 16 days (range 6 to 22 days). Five of the nine cases were not suspected clinically at the time of screening. It is concluded that TSH fulfils most of the criteria for an ideal screening test for primary hypothyroidism and a screening programme based on blood spot TSH will allow therapy to be commenced within one month of birth.

Congenital Hypothyroidism↗

PubMed1999

Neonatal screening of phenylketonuria and congenital hypothyroidism in China.

Mass screening of newborns for some congenital metabolic diseases is a tremendous achievement in the field of preventive medicine. The pilot study of neonatal screening in China was started in 1981. According to the results of 1.1 million newborn screenings from 8 big cities in the past 6 years, the incidence of phenylketonuria was 1/14,767 and congenital hypothyroidism was 1/5,469. China is a vast country with great economic differences among the different regions, making neonatal screening difficult in some areas. The national neonatal screening coverage rate is only about 2 % at the moment, but in metropolitan centers like Shanghai, the coverage rate reached 95 % in 1997.

China↗

PubMed1998

A systematic review of evidence for the appropriateness of neonatal screening programmes for inborn errors of metabolism.

BACKGROUND: Developments in screening technology and increased understanding of the natural history and treatment of inborn errors of metabolism (IEMs) have produced pressure to extend neonatal screening programmes. This review aims to assess the evidence for the appropriateness of such programmes. METHODS: A formal systematic literature review was conducted. Exclusion and inclusion criteria were used to select papers for critical appraisal by pairs of reviewers. Standard criteria were used to assess the appropriateness of neonatal screening for various IEMs. Site visits were conducted to assess new technologies for newborn screening. RESULTS: A total of 1866 papers were identified and 407 systematically selected for full critical appraisal. Published evidence confirmed that universal newborn screening for phenylketonuria (PKU) meets all of the screening criteria and justifies the expense and infrastructure necessary for the collection and testing of neonatal blood spots. There was insufficient evidence in the literature to assess the cost-effectiveness of screening for any other IEMs. There was reasonable evidence to support inclusion in extended neonatal screening of four other IEMs: biotinidase deficiency, congenital adrenal hyperplasia (CAH), medium-chain acyl CoA dehydrogenase (MCAD) deficiency and glutaric aciduria type 1 (GA1). CONCLUSIONS: Large-scale trials of screening for biotinidase, CAH, MCAD and GA1 should be conducted, with careful evaluation to establish their clinical effectiveness and cost-effectiveness in practice. Screening for the latter two disorders would be dependent upon the use of tandem mass spectrometry (tandem MS). The application of tandem MS to newborn screening requires further evaluation. The extension of neonatal screening programmes to other IEMs is not currently justified.

Evidence-Based Medicine↗

PubMed1991

Neonatal screening strategy for cystic fibrosis using immunoreactive trypsinogen and direct gene analysis.

OBJECTIVE: To assess the effectiveness of a two tier neonatal screening strategy for cystic fibrosis, which combines estimation of immunoreactive trypsinogen followed by direct gene analysis in dried blood spot samples collected at age 5 days. DESIGN: Prospective study of two tier screening strategy. The first tier of testing immunoreactive trypsinogen concentration was measured in dried blood spot samples from neonates aged 4-5 days. In the second tier direct gene analysis to detect cystic fibrosis mutations deltaF508 and deltaI506 was performed in those blood spot samples which produced the highest 1% of immunoreactive trypsinogen values. Direct gene analysis was also performed on blood spot samples from infants with suspected or confirmed meconium ileus, regardless of the immunoreactive trypsinogen value. SETTING: The South Australian Neonatal Screening Programme, operating from the department of chemical pathology at Adelaide Children's Hospital. Subjects--All 12,056 neonates born in South Australia between December 1989 and June 1990. No selection criteria were applied. INTERVENTIONS: All infants found to have two recognised cystic fibrosis mutations on direct gene analysis were referred directly for clinical management, and those with one recognised cystic fibrosis mutation were recalled for a sweat test; their families were given genetic counselling. MAIN OUTCOME MEASURES: Direct or exclusion of cystic fibrosis by sweat testing of neonates identified as being at high risk of cystic fibrosis on screening and of those at minimum risk but whose subsequent clinical history raised suspicion about the disease. RESULTS: Of the 12,056 infants screened, 11,907 (98.8%) were reported as "cystic fibrosis not indicated" on the basis of low immunoreactive trypsinogen values. Of the 148 (1.23%) infants with raised immunoreactive trypsinogen values and one (0.008%) with meconium ileus, 132 (1.09%) were reported as cystic fibrosis not indicated, four (0.033%) were identified as having cystic fibrosis, and 13 (0.108%) were recalled for sweat testing after direct gene analysis for the presence of the deltaF508 and deltaI506 cystic fibrosis mutations. No cases of affected infants are known to have been missed to date. CONCLUSION: The strategy of measurement of immunoreactive trypsinogen followed by direct gene analysis is a highly specific neonatal screen for cystic fibrosis, requiring only 2.8 families to be contacted for every case of cystic fibrosis diagnosed.

Cystic Fibrosis↗