Browsing by Author "Santos-Simarro, F."

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    Congenital generalized lipodystrophy: identification of novel variants and expansion of clinical spectrum.
    (John Wiley & Sons, 2016) Haghighi, A.; Kavehmanesh, Z.; Haghighi, A.; Salehzadeh, F.; Santos-Simarro, F.; Van Maldergem, L.; Cimbalistiene, L.; Collins, F.; Chopra, M.; Al-Sinani, S.; Dastmalchian, S.; de Silva, D.C.; Bakhti, H.; Garg, A.; Hilbert, P.
    Congenital generalized lipodystrophy (CGL) is an autosomal recessive disorder with two major subtypes. Variants in AGPAT2 result in CGL type 1 with milder manifestations, whereas BSCL2 variants cause CGL type 2 with more severe features. Muscle hypertrophy caused by lack of adipose tissue is present early in life in CGL patients. Our aim was to investigate 10 CGL patients from 7 different countries and report genotype-phenotype relationships. Genetic analysis identified disease-causing variants in AGPAT2 (five patients) and in BSCL2 (five patients), including three novel variants; c.134C>A (p.Ser45*), c.216C>G (p.Tyr72*) in AGPAT2 and c.458C>A (p.Ser153*) in BSCL2. We also report possible novel clinical features such as anemia, breast enlargement, steatorrhea, intraventricular hemorrhage and nephrolithiasis in CGL patients. Generalized lipodystrophy and muscular hypertrophy were the only features in all of our patients. Hepatomegaly was the second common feature. Some manifestations were exclusively noticed in our CGL2 patients; hypertrichosis, high-pitched voice and umbilical hernia. Bone cysts and history of seizures were noticed only in CGL1 patients. The findings of this study expand our knowledge of genotype-phenotype correlations in CGL patients. These results have important clinical applications in diagnosis and management of the CGL patients as well as in genetic counseling in families at-risk. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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    Noncoding copy-number variations are associated with congenital limb malformation
    (Nature Publishing Group, 2018) Flöttmann, R.; Kragesteen, B.K.; Geuer, S.; Socha, M.; Allou, L.; Sowińska-Seidler, A.; Bosquillon de Jarcy, L.; Wagner, J.; Jamsheer, A.; Oehl-Jaschkowitz, B.; Wittler, L.; de Silva, D.; Kurth, I.; Maya, I.; Santos-Simarro, F.; Hülsemann, W.; Klopocki, E.; Mountford, R.; Fryer, A.; Borck, G.; Horn, D.; Lapunzina, P.; Wilson, M.; Mascrez, B.; Duboule, D.; Mundlos, S.; Spielmann, M.
    PurposeCopy-number variants (CNVs) are generally interpreted by linking the effects of gene dosage with phenotypes. The clinical interpretation of noncoding CNVs remains challenging. We investigated the percentage of disease-associated CNVs in patients with congenital limb malformations that affect noncoding cis-regulatory sequences versus genes sensitive to gene dosage effects.MethodsWe applied high-resolution copy-number analysis to 340 unrelated individuals with isolated limb malformation. To investigate novel candidate CNVs, we re-engineered human CNVs in mice using clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing.ResultsOf the individuals studied, 10% harbored CNVs segregating with the phenotype in the affected families. We identified 31 CNVs previously associated with congenital limb malformations and four novel candidate CNVs. Most of the disease-associated CNVs (57%) affected the noncoding cis-regulatory genome, while only 43% included a known disease gene and were likely to result from gene dosage effects. In transgenic mice harboring four novel candidate CNVs, we observed altered gene expression in all cases, indicating that the CNVs had a regulatory effect either by changing the enhancer dosage or altering the topological associating domain architecture of the genome.Conclusion:Our findings suggest that CNVs affecting noncoding regulatory elements are a major cause of congenital limb malformations.