Congenital hypothyroidism in Northern Ireland: 40 years' experience of national screening programme.

OBJECTIVE: The incidence of congenital hypothyroidism (CHT) has progressively increased in several regions around the world but has yet to be evaluated in Northern Ireland (NI). CHT screening programme was introduced in NI in 1980 and has had a relatively unchanged protocol since its inception. The purpose of the study was to evaluate the incidence of CHT in NI from 1981 to 2020 and to explore possible contributing factors to any changes seen over the 40-year period. DESIGN: This was a retrospective database review of children diagnosed with CHT in NI between 1981 and 2020. Data was collected from the patients' medical (paper and electronic) records, including epidemiological, clinical, laboratory, and radiological features as well as outcomes at 3 years. RESULTS: Of 800,404 new-borns who were screened for CHT in NI between January 1981 and March 2020, 471 were diagnosed with CHT. There was a steady and significant increase in incidence of CHT over time with an incidence of 26 cases per 100,000 livebirths in 1981 versus 71 cases per 100,000 in 2019 (p < .001). Of these 471, 77 new-borns (16%) were born preterm. The incidence of CHT was observed twice as much in female compared to male new-borns. Diagnostic imaging including radioisotope uptake and thyroid ultrasound scans were performed in 143 cases (30%). Of these, 101 (70%) cases had thyroid dysgenesis and 42 (30%) cases had thyroid dyshormonogenesis. There were 293 (62%) of 471 patients had confirmed permanent CHT, and 90 patients (19%) had transient CHT. Over that period at least 95% of the population were recorded as having United Kingdom/Ireland as country of birth. CONCLUSION: Our findings demonstrate a nearly tripling of the CHT incidence observed over the last 40 years. This is against a background of a relatively stable population demographics. Future research should focus on the underlying cause(s) of this condition which may include changing environmental exposures in utero.

A novel IGSF1 mutation in a large Irish kindred highlights the need for familial screening in the IGSF1 deficiency syndrome.

OBJECTIVE: Loss-of-function mutations in IGSF1 result in X-linked central congenital hypothyroidism (CeCH), occurring in isolation or associated with additional pituitary hormone deficits. Intrafamilial penetrance is highly variable and a minority of heterozygous females are also affected. We identified and characterized a novel IGSF1 mutation and investigated its associated phenotypes in a large Irish kindred. DESIGN, PATIENTS AND MEASUREMENTS: A novel hemizygous IGSF1 mutation was identified by direct sequencing in two brothers with CeCH, and its functional consequences were characterized in vitro. Genotype-phenotype correlations were investigated in the wider kindred. RESULTS: The mutant IGSF1 protein (c.2318T > C, p.L773P) exhibited decreased plasma membrane expression in vitro due to impaired trafficking from the endoplasmic reticulum. Ten hemizygous males and 11 heterozygous females exhibited characteristic endocrine deficits. Ireland operates a TSH-based CH screening programme, which does not detect CeCH; therefore, genetic ascertainment preceded biochemical diagnosis of moderate CH in five of seven boys as well as their 75-year-old grandfather. Clinical features potentially attributable to hypothyroidism were variable; normal free T3 (FT3) and low/low normal reverse T3 (rT3) concentrations suggested that preferential deiodination of FT4 to FT3 may help maintain tissue euthyroidism in some individuals. However, neonatal jaundice, delayed speech or growth, and obesity were observed in seven subjects in whom diagnosis was delayed. CONCLUSIONS: As observed with other IGSF1 mutations, p.L773P results in variably penetrant IGSF1 deficiency syndrome. Our observations emphasize the need for multi-generation genetic ascertainment in affected families, especially where TSH-based CH screening programmes may fail to detect CeCH at birth.

Mortality in type 1 diabetes diagnosed in childhood in Northern Ireland during 1989-2012: A population-based cohort study.

OBJECTIVE: To investigate long-term mortality rates and causes of death in individuals diagnosed with type 1 diabetes before the age of 15 years during the period 1989-2012 or known to paediatric diabetes teams in 1989, in Northern Ireland. METHODS: A cohort of 3129 patients from the Northern Ireland Childhood Diabetes Register was linked to death registrations and underlying causes, coded according to ICD-9 or ICD-10. Standardized mortality ratios (SMRs) were calculated as the ratio of observed to expected deaths by sex, attained age, time since diagnosis, calendar period, and cause of death. RESULTS: Subjects were followed to December 31, 2012 giving 39 764 person-years of follow-up (median 12.1 years). In total, 59 subjects had died (1.5 per 1000 person-years) compared with 19.9 deaths expected, an SMR of 296 (95% confidence interval (CI) 229-382). Women had a significantly higher excess risk of mortality than men with SMRs of 535 (95% CI 361-764) and 203 (95% CI 136-291), respectively. Over half of the deaths (56%) were judged to be related or possibly related to diabetes with most of these due to acute (n = 24) or late (n = 6) complications. CONCLUSIONS: Subjects with type 1 diabetes diagnosed less than 15 years of age had 3 times the mortality risk of the general population. Over half of the deaths were related to acute or chronic complications of diabetes.

Diagnostic value of exome and whole genome sequencing in craniosynostosis.

BACKGROUND: Craniosynostosis, the premature fusion of one or more cranial sutures, occurs in ∼1 in 2250 births, either in isolation or as part of a syndrome. Mutations in at least 57 genes have been associated with craniosynostosis, but only a minority of these are included in routine laboratory genetic testing. METHODS: We used exome or whole genome sequencing to seek a genetic cause in a cohort of 40 subjects with craniosynostosis, selected by clinical or molecular geneticists as being high-priority cases, and in whom prior clinically driven genetic testing had been negative. RESULTS: We identified likely associated mutations in 15 patients (37.5%), involving 14 different genes. All genes were mutated in single families, except for IL11RA (two families). We classified the other positive diagnoses as follows: commonly mutated craniosynostosis genes with atypical presentation (EFNB1, TWIST1); other core craniosynostosis genes (CDC45, MSX2, ZIC1); genes for which mutations are only rarely associated with craniosynostosis (FBN1, HUWE1, KRAS, STAT3); and known disease genes for which a causal relationship with craniosynostosis is currently unknown (AHDC1, NTRK2). In two further families, likely novel disease genes are currently undergoing functional validation. In 5 of the 15 positive cases, the (previously unanticipated) molecular diagnosis had immediate, actionable consequences for either genetic or medical management (mutations in EFNB1, FBN1, KRAS, NTRK2, STAT3). CONCLUSIONS: This substantial genetic heterogeneity, and the multiple actionable mutations identified, emphasises the benefits of exome/whole genome sequencing to identify causal mutations in craniosynostosis cases for which routine clinical testing has yielded negative results.

Increased Population Risk of AIP-Related Acromegaly and Gigantism in Ireland.

The aryl hydrocarbon receptor interacting protein (AIP) founder mutation R304* (or p.R304* ; NM_003977.3:c.910C>T, p.Arg304Ter) identified in Northern Ireland (NI) predisposes to acromegaly/gigantism; its population health impact remains unexplored. We measured R304* carrier frequency in 936 Mid Ulster, 1,000 Greater Belfast (both in NI) and 2,094 Republic of Ireland (ROI) volunteers and in 116 NI or ROI acromegaly/gigantism patients. Carrier frequencies were 0.0064 in Mid Ulster (95%CI = 0.0027-0.013; P = 0.0005 vs. ROI), 0.001 in Greater Belfast (0.00011-0.0047) and zero in ROI (0-0.0014). R304* prevalence was elevated in acromegaly/gigantism patients in NI (11/87, 12.6%, P < 0.05), but not in ROI (2/29, 6.8%) versus non-Irish patients (0-2.41%). Haploblock conservation supported a common ancestor for all the 18 identified Irish pedigrees (81 carriers, 30 affected). Time to most recent common ancestor (tMRCA) was 2550 (1,275-5,000) years. tMRCA-based simulations predicted 432 (90-5,175) current carriers, including 86 affected (18-1,035) for 20% penetrance. In conclusion, R304* is frequent in Mid Ulster, resulting in numerous acromegaly/gigantism cases. tMRCA is consistent with historical/folklore accounts of Irish giants. Forward simulations predict many undetected carriers; geographically targeted population screening improves asymptomatic carrier identification, complementing clinical testing of patients/relatives. We generated disease awareness locally, necessary for early diagnosis and improved outcomes of AIP-related disease.

Standardised practices in the networked management of congenital hyperinsulinism: a UK national collaborative consensus.

Congenital hyperinsulinism (CHI) is a condition characterised by severe and recurrent hypoglycaemia in infants and young children caused by inappropriate insulin over-secretion. CHI is of heterogeneous aetiology with a significant genetic component and is often unresponsive to standard medical therapy options. The treatment of CHI can be multifaceted and complex, requiring multidisciplinary input. It is important to manage hypoglycaemia in CHI promptly as the risk of long-term neurodisability arising from neuroglycopaenia is high. The UK CHI consensus on the practice and management of CHI was developed to optimise and harmonise clinical management of patients in centres specialising in CHI as well as in non-specialist centres engaged in collaborative, networked models of care. Using current best practice and a consensus approach, it provides guidance and practical advice in the domains of diagnosis, clinical assessment and treatment to mitigate hypoglycaemia risk and improve long term outcomes for health and well-being.

Clinical and metabolic effects of gluten free diet in children with type 1 diabetes and coeliac disease.

BACKGROUND: Following the recommendations of The International Society for Pediatric and Adolescent Diabetes (ISPAD) in 2000, our clinic started routine screening of children with type 1 diabetes (T1D) for coeliac disease (CD). OBJECTIVES: To determine the short-term clinical and metabolic effects of gluten free diet (GFD) in a group of children with T1D and confirmed CD. METHODS: Data were collected on all children with T1D and CD between November 2000 and November 2007 before and 12 months after commencement of GFD. Data included the presence of gastrointestinal (GI) symptoms, episodes of severe hypoglycaemia, daily insulin requirements, height, weight, body mass index (BMI), glycosylated haemoglobin (HbA1c), haemoglobin, and persistence of autoantibodies. The effects of GFD on these parameters were studied and compared with those from the revised ISPAD Guidelines in 2007. RESULTS: Four hundred and sixty-eight children with T1D were screened, of whom 23 patients were diagnosed with CD. The mean age at diagnosis of T1D and CD was 6.8 years and 11.1 years, respectively. Ten out of 11 children showed improvement in their GI symptoms, while 6 out of 8 patients had no further severe hypoglycaemic episodes. Nine patients remained positive for antiendomysial antibodies after GFD. There was no significant change in the standard deviation score for height, weight, and BMI or the mean HbA1c and Hb before and after GFD. However the mean insulin requirement increased from 0.88 to 1.1 units/kg/day, which was statistically significant (p < 0.005). CONCLUSION: In our experience, GFD showed short-term benefits by reducing GI symptoms and severe hypoglycaemia while the insulin requirement increased significantly.

Resolution of Consumptive Hypothyroidism Secondary to Infantile Hepatic Hemangiomatosis with a Combination of Propranolol and Levothyroxine

Infantile hepatic hemangiomas (IHH), particularly of the diffuse subtype can, in severe cases, be associated with hepatic and cardiac failure, compartment syndrome and consumptive hypothyroidism. Early recognition and treatment of these pathologies is paramount in order to minimise the risk of long-term sequelae. We report an interesting case of a female infant who presented with systemic compromise, in the absence of large or obvious cutaneous infantile hemangiomas. Imaging identified innumerable hepatic hemangiomas, consistent with diffuse infantile hepatic hemangiomatosis. Subsequent to this, thyroid function tests confirmed an associated but comparatively rare form of hypothyroidism, known as consumptive hypothyroidism. Following joint consultation with dermatology and endocrinology she was promptly treated with oral propranolol and levothyroxine, with subsequent improvement in her clinical parameters. This case reiterates the importance of aggressive investigation and management of consumptive hypothyroidism in any infant diagnosed with IHH, particularly when there is systemic compromise. We advocate propranolol as a single first line treatment for IHH, supported by thyroid replacement when appropriate.

Thermal dysregulation in Prader-Willi syndrome: a potentially fatal complication in adolescence, not just in infancy.

A 13-year-old boy with a background of Prader-Willi syndrome (PWS) was admitted to the regional paediatric intensive care unit, with community-acquired pneumonia. Despite a week of intravenous antibiotics, resolution of inflammatory markers and resolving consolidation on radiograph, he remained feverish. Fever of unknown origin investigations were negative and he was diagnosed with central thermal dysregulation secondary to hypothalamic dysfunction in PWS. Following a hyperpyrexia period, secondary rhabdomyolysis and renal failure developed. This was successfully managed with active cooling, ventilation and haemofiltration. After weaning from haemofiltration, the patient was successfully extubated to non-invasive respiratory support.

Clinical experience in the screening and management of a large kindred with familial isolated pituitary adenoma due to an aryl hydrocarbon receptor interacting protein (AIP) mutation.

CONTEXT: Germline AIP mutations usually cause young-onset acromegaly with low penetrance in a subset of familial isolated pituitary adenoma families. We describe our experience with a large family with R304* AIP mutation and discuss some of the diagnostic dilemmas and management issues. OBJECTIVE: The aim of the study was to identify and screen mutation carriers in the family. PATIENTS: Forty-three family members participated in the study. SETTING: The study was performed in university hospitals. OUTCOME: We conducted genetic and endocrine screening of family members. RESULTS: We identified 18 carriers of the R304* mutation, three family members with an AIP-variant A299V, and two family members who harbored both changes. One of the two index cases presented with gigantism and pituitary apoplexy, the other presented with young-onset acromegaly, and both had surgery and radiotherapy. After genetic and clinical screening of the family, two R304* carriers were diagnosed with acromegaly. They underwent transsphenoidal surgery after a short period of somatostatin analog treatment. One of these two patients is in remission; the other achieved successful pregnancy despite suboptimal control of acromegaly. One of the A299V carrier family members was previously diagnosed with a microprolactinoma; we consider this case to be a phenocopy. Height of the unaffected R304* carrier family members is not different compared to noncarrier relatives. CONCLUSIONS: Families with AIP mutations present particular problems such as the occurrence of large invasive tumors, poor response to medical treatment, difficulties with fertility and management of pregnancy, and the finding of AIP sequence variants of unknown significance. Because disease mostly develops at a younger age and penetrance is low, the timing and duration of the follow-up of carriers without overt disease requires further study. The psychological and financial impact of prolonged clinical screening must be considered. Excellent relationships between the family, endocrinologists, and geneticists are essential, and ideally these families should be managed in centers with specialist expertise.

Clinical characteristics and management of cranial diabetes insipidus in infants.

AIM: Cranial diabetes insipidus (CDI) is rare in infants with no guidelines on its management. We describe the first case series, characterizing the clinical features and treatment challenges. METHOD: Retrospective case note review of infants diagnosed with CDI between April 1992 and February 2011. RESULTS: Nineteen infants (52% male) were identified. Eight were born preterm. Median (range) age at diagnosis was 24 days (5-300); preterm babies were younger at diagnosis (21 vs. 46 days). In 58% (11/19) of infants, hypernatraemia was discovered incidentally. In 37% of cases there was associated midline anomalies, however, only four patients (21%) had absent posterior pituitary signal on a magnetic resonance imaging brain scan. The most frequent (5/19) underlying diagnosis was septo-optic dysplasia. Eight patients had isolated CDI and 11 had multiple pituitary hormone deficiencies. Isolated CDI tended to be more common in preterm, compared to term babies (p=0.11). Des-amino arginine vasopressin (DDAVP) was administered intranasally in eight and orally in 11 infants. Plasma sodium nadir following DDAVP administration was lower following intranasal compared to an oral route of administration (median: 128 vs. 133 mmol/L, p=0.022). No cases resolved on follow-up. CONCLUSIONS: CDI in infants is often diagnosed incidentally. Aetiology, clinical, and imaging features are very variable, with some differences between preterm and term infants. Oral DDAVP appears to be superior to intranasal with less pronounced serum sodium fluctuations.