Vascular Ehlers-Danlos Syndrome: A Comprehensive Natural History Study in a Dutch National Cohort of 142 Patients

BACKGROUND

Vascular Ehlers-Danlos syndrome (vEDS) is a rare connective tissue disorder with a high risk for arterial, bowel, and uterine rupture, caused by heterozygous pathogenic variants in COL3A1. The aim of this cohort study is to provide further insights into the natural history of vEDS and describe genotype-phenotype correlations in a Dutch multicenter cohort to optimize patient care and increase awareness of the disease.

METHODS

Individuals with vEDS throughout the Netherlands were included. The phenotype was charted by retrospective analysis of molecular and clinical data, combined with a one-time physical examination.

RESULTS

A total of 142 individuals (50% female) participated the study, including 46 index patients (32%). The overall median age at genetic diagnosis was 41.0 years. More than half of the index patients (54.3%) and relatives (53.1%) had a physical appearance highly suggestive of vEDS. In these individuals, major events were not more frequent (P=0.90), but occurred at a younger age (P=0.01). A major event occurred more often and at a younger age in men compared with women (P<0.001 and P=0.004, respectively). Aortic aneurysms (P=0.003) and pneumothoraces (P=0.029) were more frequent in men. Aortic dissection was more frequent in individuals with a COL3A1 variant in the first quarter of the collagen helical domain (P=0.03).

CONCLUSIONS

Male sex, type and location of the COL3A1 variant, and physical appearance highly suggestive of vEDS are risk factors for the occurrence and/or early age of onset of major events. This national multicenter cohort study of Dutch individuals with vEDS provides a valuable basis for improving guidelines for the diagnosing, follow-up, and treatment of individuals with vEDS.

Germline and somatic mosaicism in a family with multiple endocrine neoplasia type 1 (MEN1) syndrome

Context Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disease caused by mutations in the tumor suppressor gene MEN1 and can be diagnosed based on clinical, familial and/or genetic criteria. We present a family in which we found both germline and somatic mosaicism for MEN1. Family description In our proband, we diagnosed MEN1. The mutation was not detected in her parents (DNA extracted from leucocytes). When her brother was found to harbor the same MEN1 mutation as our proband and, around the same time, their father was diagnosed with a neuroendocrine carcinoma, this tumor was investigated for the MEN1 mutation as well. In the histologic biopsy of this tumor, the same MEN1 mutation was detected as previously found in his children. Re-analysis of his blood using multiplex ligation-dependent probe amplification (MLPA) showed a minimal, but consistently decreased signal for the MEN1-specific MLPA probes. The deletion was confirmed in his son by high-resolution array analysis. Based on the array data, we concluded that the deletion was limited to the MEN1 gene and that the father had both germline and somatic mosaicism for MEN1. Conclusions To our knowledge, this is the first reported family with combined germline and somatic mosaicism for MEN1. This study illustrates that germline mosaicism is important to consider in apparently sporadic de novo MEN1 mutations, because of its particular importance for genetic counseling, specifically when evaluating the risk for family members and when considering the possibility of somatic mosaicism in the parent with germline mosaicism.

Mutations in N-acetylglucosamine (O-GlcNAc) transferase in patients with X-linked intellectual disability

N-Acetylglucosamine (O-GlcNAc) transferase (OGT) regulates protein O-GlcNAcylation, an essential and dynamic post-translational modification. The O-GlcNAc modification is present on numerous nuclear and cytosolic proteins and has been implicated in essential cellular functions such as signaling and gene expression. Accordingly, altered levels of protein O-GlcNAcylation have been associated with developmental defects and neurodegeneration. However, mutations in the OGT gene have not yet been functionally confirmed in humans. Here, we report on two hemizygous mutations in OGT in individuals with X-linked intellectual disability (XLID) and dysmorphic features: one missense mutation (p.Arg284Pro) and one mutation leading to a splicing defect (c.463–6T>G). Both mutations reside in the tetratricopeptide repeats of OGT that are essential for substrate recognition. We observed slightly reduced levels of OGT protein and reduced levels of its opposing enzyme O-GlcNAcase in both patient-derived fibroblasts, but global O-GlcNAc levels appeared to be unaffected. Our data suggest that mutant cells attempt to maintain global O-GlcNAcylation by down-regulating O-GlcNAcase expression. We also found that the c.463–6T>G mutation leads to aberrant mRNA splicing, but no stable truncated protein was detected in the corresponding patient-derived fibroblasts. Recombinant OGT bearing the p.Arg284Pro mutation was prone to unfolding and exhibited reduced glycosylation activity against a complex array of glycosylation substrates and proteolytic processing of the transcription factor host cell factor 1, which is also encoded by an XLID-associated gene. We conclude that defects in O-GlcNAc homeostasis and host cell factor 1 proteolysis may play roles in mediation of XLID in individuals with OGT mutations.

Splice site mutations in GH1 detected in previously (Genetically) undiagnosed families with congenital isolated growth hormone deficiency type II

BACKGROUND

Congenital isolated growth hormone deficiency (IGHD) is a rare endocrine disorder that presents with severe proportionate growth failure. Dominant (type II) IGHD is usually caused by heterozygous mutations of GH1. The presentation of newly affected family members in 3 families with dominant IGHD in whom previous genetic testing had not demonstrated a GH1 mutation or had not been performed, prompted us to identify the underlying genetic cause.

METHODS

GH1 was sequenced in 3 Caucasian families with a clinical autosomal dominant IGHD.

RESULTS

All affected family members had severe growth hormone (GH) deficiency that became apparent in the first 2 years of life. GH treatment led to a marked increase in height SDS. So far, no other pituitary dysfunctions have become apparent. In the first family a novel splice site mutation in GH1 was identified (c.172-1G>C, IVS2-1G>C). In two other families a previously reported splice site mutation (c.291+1G>A, IVS3+1G>A) was found.

CONCLUSION

These data show that several years after negative genetic testing it was now possible to make a genetic diagnosis in these families with a well-defined, clearly heritable, autosomal dominant IGHD. This underscores the importance of clinical and genetic follow-up in a multidisciplinary setting. It also shows that even without a positive family history, genetic testing should be considered if the phenotype is strongly suggestive for a genetic syndrome. Identification of pathogenic mutations, like these GH1 mutations, has important clinical implications for the surveillance and genetic counseling of patients and expands our knowledge on the genotype-phenotype correlation.

A dominant-negative GFI1B mutation in the gray platelet syndrome

The gray platelet syndrome is a hereditary, usually autosomal recessive bleeding disorder caused by a deficiency of alpha granules in platelets. We detected a nonsense mutation in the gene encoding the transcription factor GFI1B (growth factor independent 1B) that causes autosomal dominant gray platelet syndrome. Both gray platelets and megakaryocytes had abnormal marker expression. In addition, the megakaryocytes had dysplastic features, and they were abnormally distributed in the bone marrow. The GFI1B mutant protein inhibited nonmutant GFI1B transcriptional activity in a dominant-negative manner. Our studies show that GFI1B, in addition to being causally related to the gray platelet syndrome, is key to megakaryocyte and platelet development.

[Neonatal screening for congenital hypothyroidism: more than 30 years of experience in the Netherlands]

OBJECTIVE

To describe the Dutch neonatal screening programme for congenital hypothyroidism (CH).

DESIGN

Descriptive study.

METHOD

Data on neonatal screening for CH in the period 1 January 1981 through 31 December 2011 were obtained from the Department for Vaccine Supply and Prevention Programmes of the Dutch National Institute for Public Health and the Environment (RIVM), laboratories and paediatricians to whom babies with abnormal screening results were referred. The screening procedure has been amended several times. In the period 1981-1994, only T4 and TSH were measured in heel prick blood, for example. From 1995, thyroxine-binding globulin (TBG) was added to the screening protocol.

RESULTS

The participation rate was 99.7%. Before 1995 the sensitivity, specificity and positive predictive value were 94%, 99.51% and 6%, respectively. From 1995 these percentages were 98%, 99.85% and 21%, respectively. The total prevalence of CH was 1:2670 (prevalence of CH of thyroidal origin was 1:3100 and CH of central origin was 1:21,600). The percentages of patients with severe CH treated before day 15 in the periods 1981-1990, 1991-2000 and 2001-2011 were 24% (63/263), 63% (170/269) and 96% (176/184), respectively.

CONCLUSION

The sensitivity and specificity of the screening procedure has considerably increased since 1995 compared with the period before 1995. In recent years patients with severe CH were treated considerably earlier than in the first years of the screening. Neonatal screening for CH may be considered as an important success for public health care.

Loss-of-function mutations in TGFB2 cause a syndromic presentation of thoracic aortic aneurysm

Loeys-Dietz syndrome (LDS) associates with a tissue signature for high transforming growth factor (TGF)-β signaling but is often caused by heterozygous mutations in genes encoding positive effectors of TGF-β signaling, including either subunit of the TGF-β receptor or SMAD3, thereby engendering controversy regarding the mechanism of disease. Here, we report heterozygous mutations or deletions in the gene encoding the TGF-β2 ligand for a phenotype within the LDS spectrum and show upregulation of TGF-β signaling in aortic tissue from affected individuals. Furthermore, haploinsufficient Tgfb2(+/-) mice have aortic root aneurysm and biochemical evidence of increased canonical and noncanonical TGF-β signaling. Mice that harbor both a mutant Marfan syndrome (MFS) allele (Fbn1(C1039G/+)) and Tgfb2 haploinsufficiency show increased TGF-β signaling and phenotypic worsening in association with normalization of TGF-β2 expression and high expression of TGF-β1. Taken together, these data support the hypothesis that compensatory autocrine and/or paracrine events contribute to the pathogenesis of TGF-β-mediated vasculopathies.

Effects of naproxen and sulphasalazine or methotrexate on hypothalamic-pituitary-adrenal axis activity in patients with rheumatoid arthritis

OBJECTIVES

To study the effects of antirheumatic drugs on hypothalamic-pituitary-adrenal (HPA) axis activity in patients with rheumatoid arthritis (RA).

METHODS

Twenty patients with recent-onset active RA were studied before antirheumatic treatment, after 2 weeks of naproxen, and after 5½ months of additional treatment with sulphasalazine or methotrexate. The results before treatment were compared with those obtained in 20 age and sex-matched healthy controls (HC). Activity of the HPA-axis was assessed under basal conditions and during insulin tolerance tests (ITT). The ex-vivo production of interleukin (IL)-1β, tumour necrosis factor-α (TNF-α) and IL-6 in whole blood samples was measured with and without stimulation by LPS.

RESULTS

At baseline, plasma ACTH and cortisol levels were not different between patients with RA and HC. The unstimulated production of IL-6 was significantly higher in RA patients than in HC. After 2 weeks of treatment with naproxen, urinary cortisol excretion decreased significantly (p=0.03), and the area under the curve for plasma cortisol during the ITT was significantly lower (p=0.015). The LPS stimulated production of IL-1β was significantly lower compared with baseline. After 6 months, basal plasma, salivary and urinary cortisol levels, and plasma cortisol and ACTH levels during the ITT, were all unchanged in comparison to the pre-treatment period. The unstimulated ex-vivo production of IL-1β was significantly lower than before treatment.

CONCLUSIONS

Our results suggest that the non-steroidal anti-inflammatory drug naproxen suppresses the HPA-axis in the first weeks of treatment. After 6 months, this suppressive effect is no longer present, suggesting the existence of adaptive mechanisms.

Systematic review: diagnostic procedures to differentiate unilateral from bilateral adrenal abnormality in primary aldosteronism

BACKGROUND

Computed tomography (CT), magnetic resonance imaging (MRI), and adrenal vein sampling (AVS) are used to distinguish unilateral from bilateral increased aldosterone secretion as a cause of primary aldosteronism. This distinction is crucial because unilateral primary aldosteronism can be treated surgically, whereas bilateral primary aldosteronism should be treated medically.

PURPOSE

To determine the proportion of patients with primary aldosteronism whose CT or MRI results with regard to unilateral or bilateral adrenal abnormality agreed or did not agree with those of AVS.

DATA SOURCES

PubMed, MEDLINE, EMBASE, and Cochrane Library, 1977 to April 2009.

STUDY SELECTION

Studies describing adults with primary aldosteronism who underwent CT/MRI and AVS were included. Of 472 initially identified studies, 38 met the selection criteria; extractable data were available for 950 patients.

DATA EXTRACTION

The CT/MRI result was considered accurate when AVS showed unilaterally increased aldosterone secretion on the same side as the abnormality seen on CT/MRI or when AVS showed symmetric aldosterone secretion and CT/MRI revealed bilateral or no unilateral abnormality.

DATA SYNTHESIS

In 37.8% of patients (359 of 950), CT/MRI results did not agree with AVS results. If only CT/MRI results had been used to determine lateralization of an adrenal abnormality, inappropriate adrenalectomy would have occurred in 14.6% of patients (where AVS showed a bilateral problem), inappropriate exclusion from adrenalectomy would have occurred in 19.1% (where AVS showed unilateral secretion), and adrenalectomy on the wrong side would have occurred in 3.9% (where AVS showed aldosterone secretion on the opposite side).

LIMITATION

The lack of follow-up data in the included articles made it impossible to confirm that adrenalectomies were performed appropriately.

CONCLUSION

When AVS is used as the criterion standard test for diagnosing laterality of aldosterone secretion in patients with primary aldosteronism, CT/MRI misdiagnosed the cause of primary aldosteronism in 37.8% of patients. Relying only on CT/MRI may lead to inappropriate treatment of patients with primary aldosteronism.

Effect of naproxen on the hypothalamic-pituitary-adrenal axis in healthy volunteers

AIM

To study the effect of the nonsteroidal anti-inflammatory drug naproxen on the activity of the hypothalamic-pituitary-adrenal (HPA) axis in healthy volunteers.

METHODS

A double-blind, randomized study in two groups of 20 healthy volunteers was performed. The activity of the HPA axis was measured before and after the use of naproxen or placebo during a period of 2 weeks. Basal plasma adrenocorticotropic hormone (ACTH) and cortisol, 24-h urinary cortisol, and circadian cortisol rhythm in saliva were determined. Plasma ACTH and cortisol were also measured during submaximal physical exercise.

RESULTS

There were no significant differences between the placebo and naproxen groups in basal plasma ACTH [09.00 h 3.1 pmol l(-1), 95% confidence interval (CI) 2.0, 4.2, and 2.8 pmol l(-1), 95% CI 1.9, 3.7, respectively], cortisol levels (09.00 h 0.45 micromol l(-1), 95% CI 0.39, 0.51, and 0.40 micromol l(-1), 95% CI 0.35, 0.44, respectively), 24 h urinary cortisol excretion (67.5 nmol 24 h(-1), 95% CI 54.3, 80.7, and 86.8 nmol 24 h(-1), 95% CI 54.4, 119.2, respectively), circadian cortisol rhythm measured in salivary samples, or ACTH and cortisol concentrations after physical exercise. After the use of placebo or naproxen for 2 weeks, no significant change in any of the parameters occurred (ACTH 09.00 h 3.0 pmol l(-1), 95% CI 2.0, 3.9, and 3.0 pmol l(-1), 95% CI 2.2, 3.8, respectively; cortisol 09.00 h 0.45 micromol l(-1), 95% CI 0.37, 0.52, and 0.39 micromol l(-1), 95% CI 0.34, 0.44, respectively; cortisol urine 79.5 nmol 24 h(-1), 95% CI 59.5, 99.4, and 81.7 nmol 24 h(-1), 95% CI 64.0, 99.4, respectively), and no significant differences were found in these parameters between the placebo and naproxen groups.

CONCLUSIONS

The use of naproxen does not influence the activity of the HPA axis in healthy volunteers under basal circumstances or in response to physical stress.

Homozygous and heterozygous expression of a novel mutation of the acid-labile subunit

CONTEXT

Acid-labile subunit (ALS) deficiency due to homozygous inactivation of the ALS gene (IGFALS) is associated with moderate short stature, and in few cases pubertal delay. The clinical expression of heterozygosity is unknown.

OBJECTIVE

To investigate the clinical, laboratory, and radiological features of homozygous and heterozygous carriers of a novel mutation in the ALS gene in comparison with non-carriers.

SUBJECTS

Three short Kurdish brothers and their relatives.

RESULTS

The index cases presented with short stature, microcephaly, and low circulating IGF-I and IGF-binding protein-3 (IGFBP-3), and undetectable ALS levels. Two were known with a low bone mineral density and one of them had suffered from two fractures. We found a novel homozygous ALS gene mutation resulting in a premature stop codon (c.1490dupT, p.Leu497PhefsX40). The IGF-I, IGFBP-3, and ALS 150 kDa ternary complex was absent, and ALS proteins in serum were not detected with western blot. IGFPB-1 and IGFPB-2 were low and there was a mild insulin resistance. Five heterozygous carriers tended to have a lower height and head circumference than five non-carriers, and had low plasma ALS and IGFBP-3 levels. Bone mineral (apparent) density was low in two out of three homozygous carriers, and also in four out of nine relatives.

CONCLUSIONS

The clinical presentation of homozygous ALS mutations may, besides short stature, include microcephaly. Heterozygous carriers may have less statural and head growth, suggestive for a gene dosage effect.

Quality of life, developmental milestones, and self-esteem of young adults with congenital hypothyroidism diagnosed by neonatal screening

CONTEXT

With advances in the treatment of congenital hypothyroidism (CH), the neuropsychological functioning of CH patients is considerably improved. Although much is written about cognitive and motor development, little is known about emotional and social consequences for patients growing up with CH, diagnosed by neonatal screening.

OBJECTIVES

The objectives of the study were to: 1) compare health-related quality of life (HRQoL), developmental milestones also called course of life (CoL), sociodemographical outcomes, and self-esteem of CH patients with the general population; and 2) explore whether severity of CH was related to these outcomes.

DESIGN/SETTING/PATIENTS

A total of 69 young adults with CH, born in The Netherlands in 1981-1982, completed the "TNO-AZL Questionnaire for Adult's Health related Quality of Life" questionnaire, the CoL survey (developmental milestones and sociodemographical outcomes), and a self-esteem questionnaire.

MAIN OUTCOME MEASURES

HRQoL, CoL, social demographical outcomes, and self-esteem in young adults with CH were determined.

RESULTS

CH patients are more often at risk for HRQoL impairment and reported lower HRQoL on several domains (cognitive functioning, P < 0.0001; sleeping, P < 0.004; pain, P < 0.0001; daily activities, P < 0.004; vitality, P < 0.0001; aggressiveness, P < 0.0001; and depressive moods, P < 0.0001) compared with healthy adults. Patients reported a lower self-esteem (P < 0.005) and had a delayed CoL on the domain of social development (P < 0.016). There were no significant within-group differences between the severity groups for HRQoL, CoL, and self-esteem.

CONCLUSIONS

Negative consequences in terms of HRQoL, development, and self-esteem are prevalent in young adults with CH. Health care physicians should be attentive to these consequences and provide additional support (emotional and educational guidance) if necessary.

Loss of integrity of thyroid morphology and function in children born to mothers with inadequately treated Graves' disease

CONTEXT

Central congenital hypothyroidism (CH-C) in neonates born to mothers with inadequately treated Graves' disease usually needs T(4) supplementation. The thyroid and its regulatory system have not yet been extensively studied after T(4) withdrawal, until we observed disintegrated thyroid glands in some patients.

OBJECTIVE

The aim was to study the occurrence and pathogenesis of disintegrated thyroid glands in CH-C patients. DESIGN, SETTING, PATIENTS, PARTICIPANTS: Thyroid function was measured and thyroid ultrasound imaging was performed in 13 children with CH-C due to inadequately treated maternal Graves' disease after T(4)-supplementation withdrawal (group Aa). In addition, thyroid ultrasound imaging was performed in six children with CH-C born to inadequately treated mothers with Graves' disease, in whom T(4) supplementation was not withdrawn yet (group Ab) or never initiated (group Ac), in six euthyroid children born to adequately treated mothers with Graves' disease (group B), and in 10 T(4)-supplemented children with CH-C as part of multiple pituitary hormone deficiency (group C).

MAIN OUTCOME MEASURES

Thyroid function and aspect (volume, echogenicity, echotexture) were measured.

RESULTS

In group A, five children had developed thyroidal hypothyroidism characterized by persistently elevated TSH concentrations and exaggerated TSH responses after TRH stimulation. In the majority of patients in groups A and C, thyroid echogenicity and volume were decreased, and echotexture was inhomogeneous. Thyroid ultrasound imaging was normal in group B children.

CONCLUSIONS

Inadequately treated maternal Graves' disease not only may lead to CH-C but also carries an, until now, unrecognized risk of thyroid disintegration in the offspring as well. We speculate that insufficient TSH secretion due to excessive maternal-fetal thyroid hormone transfer inhibits physiological growth and development of the child's thyroid.

Neonatal screening for congenital hypothyroidism in the Netherlands: cognitive and motor outcome at 10 years of age

CONTEXT

Patients with thyroidal congenital hypothyroidism (CH-T) born in The Netherlands in 1981-1982 showed persistent intellectual and motor deficits during childhood and adulthood, despite initiation of T(4) supplementation at a median age of 28 d after birth.

OBJECTIVE

The present study examined whether advancement of treatment initiation to 20 d had resulted in improved cognitive and motor outcome.

DESIGN/SETTING/PATIENTS

In 82 Dutch CH-T patients, born in 1992 to 1993 and treated at a median age of 20 d (mean, 22 d; range, 2-73 d), cognitive and motor outcome was assessed (mean age, 10.5 yr; range, 9.6-11.4 yr). Severity of CH-T was classified according to pretreatment free T(4) concentration.

MAIN OUTCOME MEASURE

Cognitive and motor outcome of the 1992-1993 cohort in comparison to the 1981 to 1982 cohort was the main outcome measure.

RESULTS

Patients with severe CH-T had lower full-scale (93.7), verbal (94.9), and performance (93.9) IQ scores than the normative population (P < 0.05), whereas IQ scores of patients with moderate and mild CH-T were comparable to those of the normative population. In all three severity subgroups, significant motor problems were observed, most pronounced in the severe CH-T group. No correlations were found between starting day of treatment and IQ or motor outcome.

CONCLUSIONS

Essentially, findings from the 1992-1993 cohort were similar to those of the 1981-1982 cohort. Apparently, advancing initiation of T(4) supplementation from 28 to 20 d after birth did not result in improved cognitive or motor outcome in CH-T patients.

The effect of life-long thyroxine treatment and physical activity on bone mineral density in young adult women with congenital hypothyroidism

OBJECTIVE

Normalization of plasma thyrotropin in T4-supplemented patients with thyroidal congenital hypothyroidism (CH) requires elevated plasma FT4-concentrations compared to patients with acquired thyroidal hypothyroidism. We investigated bone mineral density (BMD) in patients with CH.

PATIENTS AND METHODS

BMD was measured in 14 adult women with thyroidal CH and nine age-matched female controls.

RESULTS

There were no significant differences between patients and controls for femoral neck bone mineral content (BMC) (38.6 vs 37.6 g), BMD (0.98 vs 1.01 g/cm(2)), T-score (0.1 vs 0.3 SD) and z-score (0.1 vs 0.3 SD) and for spine BMC (63.1 vs 71.9 g). The differences in spine BMD (0.97 vs 1.09 g/cm(2)), T-score (-0.7 vs 0.4 SD) and z-score (-0.5 vs 0.6 SD) were significant (p = 0.025, p = 0.023, and p = 0.021, respectively).

CONCLUSIONS

Although BMD in patients with CH was slightly lower compared to controls, all scores were within the reference range. This does not support the hypothesis that the upwards shifted plasma FT4-concentrations in patients treated for CH have a deleterious effect on BMD.

[Central congenital hypothyroidism due to Graves' disease in the mother]

Two male twins were born at a gestational age of 30 weeks. Five days after delivery, the mother was diagnosed with Graves' disease. The thyroid function in the neonates was therefore evaluated, which led to the detection of central congenital hypothyroidism (central CHT), even though the neonatal CHT-screening had been reported to be normal. Both boys were treated with thyroxine up to the age of nine months. It was then established that their development had been uneventful. Maternal Graves' disease can, due to the presence of anti-thyroid stimulating hormone (TSH) receptor antibodies and the maternal use of anti-thyroid drugs, result in thyroid dysfunction in the neonate. Neonates born to mothers with Graves' disease are at risk of developing central CHT. This occurs especially in children of mothers who are not treated or are inadequately treated during pregnancy. In view of the importance of thyroid hormone for brain development, children with central CHT are at risk for neurodevelopmental problems if thyroid dysfunction is not detected and treated early. The Dutch screening for congenital hypothyroidism is based on thyroxine (T4), TSH and thyroid-binding globulin. This makes it possible to detect central CHT. However, in prematurely born infants this disease may be missed because in this subgroup, referral is only based on increased TSH levels, which may not be present.

Neonatal screening for congenital hypothyroidism based on thyroxine, thyrotropin, and thyroxine-binding globulin measurement: potentials and pitfalls

CONTEXT

The Dutch T(4)-TSH-TBG-based neonatal screening program detects patients with congenital hypothyroidism (CH) of thyroidal (CH-T) as well as central (CH-C) origin. The numbers and characteristics of true-positive and false-positive referrals will differ from other, predominantly TSH-based, screening methods.

OBJECTIVE

The present study describes the characteristics of the referred neonates, both CH patients and false positives, and of the reported CH patients with a false-negative screening result born in the study period.

DESIGN, SETTING, PATIENTS, AND MAIN OUTCOME MEASURE

For each referred child born between April 1, 2002, and May 31, 2004, screening results and first venous sample results were recorded and classified as transient or permanent CH-T or CH-C or as no CH.

RESULTS

In the study period, 430,764 children were screened. Of the 772 children with abnormal screening results, 224 (29%) had CH; another 13 CH patients did not have abnormal screening results, giving an overall CH incidence of 1:1800. Incidences of permanent CH, permanent CH-T, permanent CH-C, and transient CH were 1:2200, 1:2500, 1:21,000, and 1:12,000, respectively. The most frequent explanations for the 548 false-positive referrals (71% of the referred cohort) were severe illness and TBG deficiency (occurring in 198 and 200 children, respectively).

CONCLUSIONS

The Dutch incidence figures for CH belong to the highest worldwide, suggesting that the T(4)-TSH-TBG screening program is an efficient method to detect CH of variable etiology and severity. Still, a small percentage of children with CH escaped detection via this screening approach. Severe illness and TBG deficiency appear to be responsible for the majority of false-positive referrals.

Trisomy 21 causes persistent congenital hypothyroidism presumably of thyroidal origin

OBJECTIVE AND DESIGN

Lowered neonatal plasma thyroxine (T(4)) and mildly elevated thyrotropin concentrations together with developmental benefits from neonatally started T(4) treatment in a randomized clinical trial demonstrated Down syndrome (DS) neonates to be mildly hypothyroid, at least during their first weeks of life. To prove that this hypothyroid state persists beyond this period in all, and to elucidate its etiology, we evaluated the course of the thyroid function determinants in all DS infants participating in this 24-month trial.

MAIN OUTCOME

Mean plasma thyrotropin concentrations and thyrotropin frequency distributions of 97 placebo-treated infants were persistently shifted to substantially higher concentrations, while free T(4) frequency distributions were in the lower two thirds of the reference interval. Mean thyroglobulin concentrations were normal. To normalize plasma thyrotropin, T(4)-treated DS infants (N = 99) needed rather high free T(4) concentrations, like T(4)- treated non-DS children with thyroidal congenital hypothyroidism. At ages 12 and 24 months, thyroid peroxidase antibodies were detected in 1.1% and 5.4% of all DS infants.

CONCLUSIONS

These findings suggest that as a group DS infants have a novel type of persistent mild congenital hypothyroidism, presumably of thyroidal origin. The group character suggests a direct relation with the trisomic state of chromosome 21, hypothetically through genomic dosage imbalance of dosage-sensitive genes interfering with thyroid hormone production.

Intellectual and motor development of young adults with congenital hypothyroidism diagnosed by neonatal screening

CONTEXT

Long-term follow-up data on cognitive and motor functioning in adult patients with congenital hypothyroidism, diagnosed by neonatal screening, are scarce. Hence, it is still unclear whether the frequently reported cognitive and motor deficits observed during childhood persist in adulthood.

OBJECTIVE

The objective of this study was to examine cognitive and motor functioning in young adults with congenital hypothyroidism, born in the first 2 yr after the introduction of the Dutch neonatal screening program.

DESIGN/SETTING/PATIENTS

Seventy patients were tested (mean age, 21.5 yr); 49 of them were previously tested at 9.5 yr. The median age at the start of treatment was 28 d (range, 4-293 d). Congenital hypothyroidism was classified as severe, moderate, or mild, according to pretreatment T(4) concentrations.

MAIN OUTCOME MEASUREMENT

The main outcome measurement was the influence of the severity of congenital hypothyroidism and age at which T(4) supplementation was started on cognitive and motor outcome.

RESULTS

Patients, particularly those with severe congenital hypothyroidism, had significantly higher (i.e. worse) motor scores (total score, 7.8; ball skills, 2.0; balance, 4.1) compared with controls (total score, 3.2; ball skills, 0.7; balance, 1.1), and lower full-scale (95.8), verbal (96.4), and performance (95.6) intelligence quotient (IQ) scores than the normal population. No significant change in IQ from childhood to adulthood was found, and for the majority of patients, motor score classification remained the same. The severity of congenital hypothyroidism, but not the starting day of treatment, was correlated with IQ and motor scores.

CONCLUSIONS

It is concluded that the severity of congenital hypothyroidism, but not the timing of treatment initiation, is an important factor determining long-term cognitive and motor outcome. Clearly, detrimental effects on developmental outcome in patients with congenital hypothyroidism persist over time.

Disturbance of the fetal thyroid hormone state has long-term consequences for treatment of thyroidal and central congenital hypothyroidism

BACKGROUND

During T(4) supplementation of patients with thyroidal (primary) congenital hypothyroidism (CH) TSH concentrations are frequently elevated despite free T(4) (FT(4)) concentrations being well within the reference range. To examine the thyroid's regulatory system, we analyzed thyroid function determinants in children with congenital and acquired thyroid disorders and in controls.

METHODS

Retrospectively, plasma FT(4), TSH, and T(3) concentrations were analyzed in T(4)-supplemented children aged 0.5-20.0 yr with thyroidal CH, central (secondary or tertiary) CH, or autoimmune thyroid disease and in control children with type 1 diabetes mellitus.

RESULTS

When TSH was within the reference range (0.4-4.0 mU/liter), mean FT(4) in thyroidal CH [1.65 ng/dl; 95% confidence interval (CI), 1.62-1.67] was significantly higher than in autoimmune thyroid disease (1.15 ng/dl; 95% CI, 1.11-1.19) and diabetes (1.08 ng/dl; 95% CI, 1.06-1.10). In central CH, when TSH was less than or equal to 0.02 mU/liter, mean FT(4) was 1.27 ng/dl (95% CI, 1.24-1.29). When FT(4) was within the reference range (0.78-1.79 ng/dl), 43% of the TSH measurements in thyroidal CH were more than 4.0 mU/liter, compared with 18% in autoimmune thyroid disease and 0% in type 1 diabetes mellitus; in central CH, 95% of TSH measurements were less than 0.4 mU/liter.

CONCLUSIONS

In T(4)-supplemented patients with thyroidal CH, when TSH concentrations are established within the reference range, FT(4) concentrations tend to be elevated, and vice versa. Because this phenomenon could not be observed in acquired thyroidal hypothyroidism, we hypothesize that a pre- and/or perinatal hypothyroid state shifts the setpoint of the thyroid's regulatory system. In central CH, when FT(4) concentrations are established within the reference range, the pituitary secretes only minute amounts of TSH. For monitoring T(4) supplementation, reference ranges for FT(4) and TSH should be adapted to the etiology of hypothyroidism.

Central congenital hypothyroidism due to gestational hyperthyroidism: detection where prevention failed

Much worldwide attention is given to the adverse effects of maternal Graves' disease on the fetal and neonatal thyroid and its function. However, reports concerning the adverse effects of maternal Graves' disease on the pituitary function, illustrated by the development of central congenital hypothyroidism (CCH) in the offspring of these mothers, are scarce. We studied thyroid hormone determinants of 18 children with CCH born to mothers with Graves' disease. Nine mothers were diagnosed after pregnancy, the majority after their children were detected with CCH by neonatal screening. Four mothers were diagnosed during pregnancy and treated with antithyroid drugs since diagnosis. Another four mothers were diagnosed before pregnancy, but they used antithyroid drugs irregularly; free T(4) concentrations less than 1.7 ng/dl (<22 pmol/liter) were not encountered during pregnancy. All neonates had decreased plasma free T(4) concentrations (range 0.3-0.9 ng/dl, 3.9-11.5 pmol/liter); plasma TSH ranged between 0.1 and 6.6 mU/liter. TRH tests showed pituitary dysfunction. Seventeen children needed T(4) supplementation. Because all mothers were insufficiently treated during pregnancy, it is hypothesized that a hyperthyroid fetal environment impaired maturation of the fetal hypothalamic-pituitary-thyroid system. The frequent occurrence of this type of CCH (estimated incidence 1:35000) warrants early detection and treatment to minimize the risk of cerebral damage. A T(4)-based screening program appears useful in detecting this type of CCH. However, the preferential and presumably best strategy to prevent CCH caused by maternal Graves' disease is preserving euthyroidism throughout pregnancy.

Idiopathic precocious puberty versus puberty in adopted children; auxological response to gonadotrophin-releasing hormone agonist treatment and final height

OBJECTIVE

The objective of this study was to evaluate the characteristics of puberty and response to gonadotrophin-releasing hormone (GnRH) agonist treatment in adopted children compared with children with idiopathic precocious puberty (IPP).

METHODS

We studied 17 girls with central IPP (group A) and 11 girls adopted from Asia and Central and South America (group B) with respect to auxological data at presentation of puberty and response to GnRH agonist treatment.

RESULTS

In adopted girls, age at onset of puberty was later and duration of treatment was shorter. At the start of treatment, height-standard deviation score (H-SDS) was +1.67 s.d. in group A. In group B, H-SDS was comparably increased (+0.04 s.d.) assuming that the mean H-SDS in their native country is lower than the mean on the Dutch curve. During treatment, H-SDS decreased in both groups. Group A reached a final height (FH) of 166.2 cm (-0.3 s.d.) and group B of 156.1 cm (-1.9 s.d.). Predicted adult height (PAH) at the start of treatment underestimated FH in group A and overestimated FH in group B. At the end of treatment, PAH overestimated FH in both groups. The SDS for weight was above the mean in both groups at the start of treatment and increased even more during treatment. The age of occurrence of menses after treatment was stopped was the same in both groups (12.7 and 12.8 Years respectively).

CONCLUSION

Despite the difference in timing of puberty between girls with IPP and adopted girls with early puberty, their response to treatment was similar in many aspects.

Dynamics of the plasma concentrations of TSH, FT4 and T3 following thyroxine supplementation in congenital hypothyroidism

OBJECTIVE

The dynamics of the plasma concentrations of various diagnostic determinants of thyroid function were analysed in children with congenital hypothyroidism (CH) after the start of T4 supplementation. The description of the biochemical dynamics of TSH and free T4 (FT4) during the first period of thyroxine treatment is important to depict the practical outlines of the initial dosage of T4 and dosage adjustments for newborns with variable forms of CH.

DESIGN

A retrospective analysis was performed of frequent plasma TSH, total T4 (T4), FT4 and total T3 (T3) measurements in 30 CH neonates during the first weeks of treatment, treated with initial daily T4 dosages ranging from 4.8 to 11.1 microg/kg.

RESULTS

A 50% reduction in the initial plasma TSH concentration was achieved after 3-4 days of treatment, independent of CH severity. At a median of 32 days after the start of T4 supplementation, plasma TSH ranged between 0.4 and 4.0 mU/l. The mean interval needed for FT4 to reach the age-related normal values (12-29 pmol/l) was 3 days. The increase in plasma T3 concentrations levelled off within a few days, when T4 reached concentrations of around 100 nmol/l.

CONCLUSIONS

Plasma T3 and FT4 concentrations reach the normal range a few days after thyroxine treatment is started. By contrast, normalization of plasma TSH concentration takes several weeks. At the time that plasma TSH is normalized, CH neonates show a higher range of plasma FT4 concentrations than the normal range. When TSH normalization is the goal of treatment in CH, the target range for plasma FT4 during treatment in the first months needs to be adapted. During the first month of treatment the plasma TSH concentration is not helpful in assessing the proper T4 supplementation dosage. Once plasma TSH has reached normal values, it becomes a reliable determinant in addition to plasma FT4.

Inactivating mutations in the gene for thyroid oxidase 2 (THOX2) and congenital hypothyroidism

BACKGROUND

Several genetic defects are associated with permanent congenital hypothyroidism. Immunologic, environmental, and iatrogenic (but not genetic) factors are known to induce transient congenital hypothyroidism, which spontaneously resolves within the first months of life. We hypothesized that molecular defects in the thyroid oxidase system, which is composed of at least two proteins, might be involved in the pathogenesis of permanent or transient congenital hypothyroidism in babies with defects in iodide organification, for which the oxidase system is required.

METHODS

Nine patients were recruited who had idiopathic congenital hypothyroidism (one with permanent and eight with transient hypothyroidism) and an iodide-organification defect and who had been identified by the screening program for congenital hypothyroidism. The DNA of the patients and their relatives was analyzed for mutations in the genes for thyroid oxidase 1 (THOX1 ) and 2 (THOX2 ).

RESULTS

The one patient with permanent and severe thyroid hormone deficiency and a complete iodide-organification defect had a homozygous nonsense mutation in the THOX2 gene that eliminates all functional domains of the protein. Three of the eight patients with mild transient congenital hypothyroidism and a partial iodide-organification defect had heterozygous mutations in the THOX2 gene that prematurely truncate the protein, thus abolishing its functional domains.

CONCLUSIONS

Biallelic inactivating mutations in the THOX2 gene result in complete disruption of thyroid-hormone synthesis and are associated with severe and permanent congenital hypothyroidism. Monoallelic mutations are associated with milder, transient hypothyroidism caused by insufficient thyroidal production of hydrogen peroxide, which prevents the synthesis of sufficient quantities of thyroid hormones to meet the large requirement for thyroid hormones at the beginning of life.