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In 2016 a new syndrome with postnatal short stature and low IGF1 bioavailability caused by biallelic loss-of-function mutations in the gene encoding the metalloproteinase pregnancy-associated plasma protein A2 (PAPP-A2) was described in two families. Here we report two siblings of a third family from Saudi Arabia with postnatal growth retardation and decreased IGF1 availability due to a new homozygous nonsense mutation (p.Glu886* in exon 7) in PAPPA2. The two affected males showed progressively severe short stature starting around 8 years of age, moderate microcephaly, decreased bone mineral density, and high circulating levels of total IGF1, IGFBP3, and the IGF acid-labile subunit (IGFALS), with decreased free IGF1 concentrations. Interestingly, circulating IGF2 and IGFBP5 were not increased. An increase in growth velocity and height was seen in the prepuberal patient in response to rhIGF1. These patients contribute to the confirmation of the clinical picture associated with PAPP-A2 deficiency and that the PAPPA2 gene should be studied in all patients with short stature with this characteristic phenotype. Hence, pediatric endocrinologists should measure circulating PAPP-A2 levels in the study of short stature as very low or undetectable levels of this protein can help to focus the diagnosis and treatment., CIBER fisiopatología de obesidad y nutrición (CI, Grant/Award Number: PI19/00166)

The aim of this study was to determine the attitude of Saudi Arabians to research involving storage and use of human tissues from which genetic information may be derived and to assess their willingness to donate tissue samples to biobanks. In a cross-sectional interview study of 1051 outpatients at a hospital in Riyadh city, 68.8% had a positive attitude towards biomedical research and 78.4% were willing to allow use of excess surgical tissues for research purposes. Participants were less willing to allow the use of tissue or organs from a deceased relative. Logistic regression analysis found that predictors for a positive attitude to biomedical research and to use of tissue in research were: female sex, higher level of education, previous experience of blood testing and previous participation in health-related research. The attitudes towards biomedical research among the participants were satisfactory and comparable to findings from other countries.

The syndrome of congenital hypoparathyroidism, mental retardation, facial dysmorphism and extreme growth failure (HRD or Sanjad-Sakati syndrome; OMIM 241410) is an autosomal recessive disorder reported almost exclusively in Middle Eastern populations. A similar syndrome with the additional features of osteosclerosis and recurrent bacterial infections has been classified as autosomal recessive Kenny-Caffey syndrome (AR-KCS; OMIM 244460). Both traits have previously been mapped to chromosome 1q43-44 (refs 5,6) and, despite the observed clinical variability, share an ancestral haplotype, suggesting a common founder mutation. We describe refinement of the critical region to an interval of roughly 230 kb and identification of deletion and truncation mutations of TBCE in affected individuals. The gene TBCE encodes one of several chaperone proteins required for the proper folding of alpha-tubulin subunits and the formation of alpha-beta-tubulin heterodimers. Analysis of diseased fibroblasts and lymphoblastoid cells showed lower microtubule density at the microtubule-organizing center (MTOC) and perturbed microtubule polarity in diseased cells. Immunofluorescence and ultrastructural studies showed disturbances in subcellular organelles that require microtubules for membrane trafficking, such as the Golgi and late endosomal compartments. These findings demonstrate that HRD and AR-KCS are chaperone diseases caused by a genetic defect in the tubulin assembly pathway, and establish a potential connection between tubulin physiology and the development of the parathyroid.

The aim of this study was to determine the attitude of Saudi Arabians to research involving storage and use of human tissues from which genetic information may be derived and to assess their willingness to donate tissue samples to biobanks. In a cross-sectional interview study of 1051 outpatients at a hospital in Riyadh city, 68.8% had a positive attitude towards biomedical research and 78.4% were willing to allow use of excess surgical tissues for research purposes. Participants were less willing to allow the use of tissue or organs from a deceased relative. Logistic regression analysis found that predictors for a positive attitude to biomedical research and to use of tissue in research were: female sex, higher level of education, previous experience of blood testing and previous participation in health-related research. The attitudes towards biomedical research among the participants were satisfactory and comparable to findings from other countries.

Background: Joubert syndrome (JS) is an autosomal recessive disorder characterised by hypotonia, ataxia, mental retardation, altered respiratory pattern, abnormal eye movements, and a brain malformation known as the molar tooth sign (MTS) on cranial MRI. Four genetic loci have been mapped, with two genes identified ( AHI1 and NPHP1 ). Methods: We screened a cohort of 117 JS subjects for AHI1 mutations by a combination of haplotype analysis and sequencing of the gene, and for the homozygous NPHP1 deletion by sequencing and marker analysis. Results: We identified a total of 15 novel AHI1 mutations in 13 families, including nonsense, missense, splice site, and insertion mutations, with some clustering in the WD40 domains. Eight families were consanguineous, but no single founder mutation was apparent. In addition to the MTS, retinal dystrophy was present in 11 of 12 informative families; however, no subjects exhibited variable features of JS such as polydactyly, encephalocele, colobomas, or liver fibrosis. In contrast to previous reports, we identified two families with affected siblings who developed renal disease consistent with nephronophthisis (NPH) in their 20s. In addition, two individuals with classic NPH were found to have homozygous NPHP1 deletions. Conclusions: Overall, 11% of subjects had AHI1 mutations, while ∼2% had the NPHP1 deletion, representing a total of less than 15% in a large JS cohort. Some preliminary genotype-phenotype correlations are possible, notably the association of renal impairment, specifically NPH, in those with NPHP1 deletions. Subjects with AHI1 mutations may be at risk of developing both retinal dystrophy and progressive kidney disease.

The association of dysmorphic features and failure of one or more bone marrow cell lines is well known. Examples are Fanconi's anemia and Diamond-Blackfan anemia. This report describes 3 similarly affected children from consanguineous parents, all showing low birth weight, severe growth retardation, distinct facial features, microcephaly, mental retardation and onset of severe pancytopenia in infancy without increased chromosomal breakage. We conclude that these cases represent a new familial autosomal recessive bone marrow failure syndrome.