hrp0098p2-48 | Bone, Growth Plate and Mineral Metabolism | ESPE2024

Two likely compound heterozygous variants in SLC34A1 causing idiopathic infantile hypercalcemia (IIH) type 2 - a case report

Maria Duffert Christin , Choukair Daniela , Syrbe Steffen , Henje Driedger Jan , Platzer Konrad , Bettendorf Markus

Children affected by idiopathic infantile hypercalcemia (IIH) may develop polyuria, polydipsia, failure to thrive, developmental delay and nephrocalcinosis already during the first weeks of life. Elevated levels of activated 1-,25(OH)2D3 have been shown to cause the characteristic increase in serum calcium levels in this disorder. Two major underlying genetic causes have been identified so far: in IIH type 1 loss-of-function mutations in CYP24A1 ...

hrp0097p1-510 | Growth and Syndromes | ESPE2023

Tuberous sclerosis complex 1 (TSC1) deficiency leads to increased proliferation of adipose progenitor cells – case report and in vitro studies

Garten Antje , Hentschel Julia , Richter Sandy , Kiep Henriette , Arelin Maria , Platzer Konrad , Merkenschlager Andreas , Kiess Wieland , Mayer Steffi , Abou Jamra Rami , Le Duc Diana , Gerthe Kerkhof , Anita Hokken-Koelega

Introduction&Aim: Activation of mechanistic target of rapamycin (mTOR) as a major regulator of adipogenesis and lipid accumulation is controlled by upstream regulators hamartin/tuberous sclerosis complex (TSC) 1 and tuberin/TSC2. Hamartin and tuberin form a protein complex that inhibits signal transduction to mTOR. The impact of TSC1 deficiency is not clearly defined in human adipose tissue. We identified a likely pathogenic TSC1 splicing variant in a lipo...

hrp0098p2-333 | Late Breaking | ESPE2024

Accelerated growth of preadipocyte cultures with TSC1 downregulation might be linked to lipoma development and can be reversed by mTOR or PI3K inhibition

Friedrich Julika , Kirstein Anna , Hentschel Julia , Richter Sandy , Kiep Henriette , Arelin Maria , Konrad Platzer , Schulz Torsten , Merkenschlager Andreas , Kiess Wieland , Abou Jamra Rami , Mayer Steffi , Le Duc Diana , Garten Antje

Background: Tuberous Sclerosis Complex Subunit 1 (TSC1) encodes for the growth inhibitory protein hamartin, which suppresses mTOR signaling. Patients with TSC1 pathogenic variants are prone to developing benign tumors in the brain, kidneys, heart, skin, lungs, and other organs. We identified a likely pathogenic heterozygous germline TSC1 splicing variant NM_000368.5: c.737 +3A>G, r.664_737del, p. (Pro222Valfs*8) in a boy ...