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Objectives: To to define the frequency and patterns of congenital heart disease (CHD) among children with Down syndrome (DS) in Northwest Saudi Arabia. Methods: We included children with confirmed DS referred to the regional pediatric cardiology unit in Madinah Maternity and Children Hospital between January 2008 and December 2013. Children were identified from the unit’s data-base and the charts were reviewed retrospectively. We excluded term and preterm children with patent ducts arteriosus (PDA) and persistent foramen oval spontaneously resolved during the first 4 weeks of life. Results: A total of 302 children with DS were identified (50.3% male). Of these, 177 (58.6%) had CHD. Atrioventricular septal defect (AVSD) was the most frequent lesion identified in 72/177 (40.7%) followed by mixed left to right shunt defects (14.7%) and secundum atrial septal defect (ASD) (11.8%). Ventricular septal defect was detected in 10.7% and 8.5% had PDA beyond the neonatal period. There was no gender difference in the frequency of CHD (p=0.9) and the presence of CHD was not related to the genetic cause of DS (p=0.9). Conclusion: The frequency of CHD in our DS cohort is comparable with Europe, Asia, and other KSA regions. However its pattern appears to be different from some areas in KSA.

Resistance to thyroid hormone ? (RTH?) due to homozygous THRB defects is exceptionally rare, with only five kindreds reported worldwide. Cardiac dysfunction, which can be life-threatening, is recognized in the disorder. Here we describe the clinical, metabolic, ophthalmic, and cardiac findings in a 9-year-old boy harboring a biallelic THRB mutation (R243Q), along with biochemical, physiologic, and cardiac responses to carbimazole and triiodothyroacetic acid (TRIAC) therapy. The patient exhibits recognized features (goiter, nonsuppressed thyroid-stimulating hormone levels, upper respiratory tract infections, hyperactivity, low body mass index) of heterozygous RTH?, with additional characteristics (dysmorphic facies, winging of scapulae) and more markedly elevated thyroid hormone levels, associated with the homozygous form of the disorder. Notably, an older sibling with similar clinical features and probable homozygous RTH? had died of cardiac failure at age 13 years. Features of early dilated cardiomyopathy in our patient prompted combination treatment with carbimazole and TRIAC. Careful titration of therapy limited elevation in TSH levels and associated increase in thyroid volume. Subsequently, sustained reduction in thyroid hormones with normal TSH levels was reflected in lower basal metabolic rate, gain of lean body mass, and improved growth and cardiac function. A combination of antithyroid drug and TRIAC therapy may prevent thyrotoxic cardiomyopathy and its decompensation in homozygous or even heterozygous RTH? in which life-threatening hyperthyroid features predominate.

Context: Lower TSH screening cutoffs have doubled the ascertainment of congenital hypothyroidism (CH), particularly cases with a eutopically located gland-in-situ (GIS). Although mutations in known dyshormonogenesis genes or TSHR underlie some cases of CH with GIS, systematic screening of these eight genes has not previously been undertaken. Objective: Our objective was to evaluate the contribution and molecular spectrum of mutations in eight known causative genes (TG, TPO, DUOX2, DUOXA2, SLC5A5, SLC26A4, IYD, and TSHR) in CH cases with GIS. Patients, Design, and Setting: We screened 49 CH cases with GIS from 34 ethnically diverse families, using next-generation sequencing. Pathogenicity of novel mutations was assessed in silico. Results: Twenty-nine cases harbored likely disease-causing mutations. Monogenic defects (19 cases) most commonly involved TG (12), TPO (four), DUOX2 (two), and TSHR (one). Ten cases harbored triallelic (digenic) mutations: TG and TPO (one); SLC26A4 and TPO (three), and DUOX2 and TG (six cases). Novel variants overall included 15 TG, six TPO, and three DUOX2 mutations. Genetic basis was not ascertained in 20 patients, including 14 familial cases. Conclusions: The etiology of CH with GIS remains elusive, with only 59% attributable to mutations in TSHR or known dyshormonogenesis-associated genes in a cohort enriched for familial cases. Biallelic TG or TPO mutations most commonly underlie severe CH. Triallelic defects are frequent, mandating future segregation studies in larger kindreds to assess their contribution to variable phenotype. A high proportion (∼41%) of unsolved or ambiguous cases suggests novel genetic etiologies that remain to be elucidated., TG, TPO, DUOX2, DUOXA2, SLC5A5, SLC26A4, IYD and TSHR genes were screened in 49 cases of congenital hypothyroidism with eutopic gland-in-situ. 59% were solved including cases with triallelic mutations.

Context: Lower TSH screening cutoffs have doubled the ascertainment of congenital hypothyroidism (CH), particularly cases with a eutopically located gland-in-situ (GIS). Although mutations in known dyshormonogenesis genes or TSHR underlie some cases of CH with GIS, systematic screening of these eight genes has not previously been undertaken. Objective: Our objective was to evaluate the contribution and molecular spectrum of mutations in eight known causative genes (TG, TPO, DUOX2, DUOXA2, SLC5A5, SLC26A4, IYD, and TSHR) in CH cases with GIS. Patients, Design, and Setting:We screened 49 CH cases with GIS from 34 ethnically diverse families, using next-generation sequencing. Pathogenicity of novel mutations was assessed in silica. Results: Twenty-nine cases harbored likely disease-causing mutations. Monogenic defects (19 cases) most commonly involved TG (12), TPO (four), DUOX2 (two), and TSHR (one). Ten cases harbored triallelic (digenic) mutations: TG and TPO (one); SLC26A4 and TPO (three), and DUOX2 and TG (six cases). Novel variants overall included 15 TG, six TPO, and three DUOX2 mutations. Genetic basis was not ascertained in 20 patients, including 14 familial cases. Conclusions: The etiology of CH with GIS remains elusive, with only 59% attributable to mutations in TSHR or known dyshormonogenesis-associated genes in a cohort enriched for familial cases. Biallelic TG or TPO mutations most commonly underlie severe CH. Triallelic defects are frequent, mandating future segregation studies in larger kindreds to assess their contribution to variable phenotype. A high proportion (-41%) of unsolved or ambiguous cases suggests novel genetic etiologies that remain to be elucidated. Wellcome Trust European Commission - 100585/Z/12/Z - 095564/Z/11/Z - 098051 - WT091310 UK Research & Innovation (UKRI) Medical Research Council UK (MRC) - MC_UU_12012/5/B European Commission National Institute for Health Research (NIHR) - (NF-SI-0514-10176) NIHR (CL-2012-06-005)