hrp0097fc2.2 | Bone, Growth Plate and Mineral Metabolism | ESPE2023

First Results of the Global ALPL Gene Variant Classification Project

R Farman Mariam , Rehder Catherine , Malli Theodora , Rockman-Greenberg Cheryl , Dahir Kathryn , Ángel Martos-Moreno Gabriel , Linglart Agnès , Ozono Keiichi , Seefried Lothar , del Angel Guillermo , Högler Florian , Barbazza Francesca , K John Lisa , M. A. Delana Mudiyanselage Sewmi , Burner Nading Erica , Huggins Erin , T Rush Eric , El-Gazzar Ahmed , S Kishnani Priya , Webersinke Gerald , Högler Wolfgang

Background: Hypophosphatasia (HPP) is an inherited multisystem disorder predominantly affecting the mineralization of bones and teeth. HPP is caused by pathogenic variants in ALPL, which encodes tissue non-specific alkaline phosphatase. A major challenge in diagnosing HPP is interpreting variants in ALPL classified as variants of uncertain significance (VUS) according to ACMG/AMP criteria, creating uncertainty in patients and treating physicians resulting in d...

hrp0098p1-17 | Bone, Growth Plate and Mineral Metabolism 1 | ESPE2024

New clinical phenotypes associated with ALPL mutations

R Farman Mariam , Rehder Catherine , Malli Theodora , Rockman-Greenberg Cheryl , Dahir Kathryn , Ángel Martos-Moreno Gabriel , Linglart Agnès , Ozono Keiichi , Seefried Lothar , del Angel Guillermo , Högler Florian , Montero-Lopez Rodrigo , Barbazza Francesca , Burner Nading Erica , Huggins Erin , T Rush Eric , K Javaid Muhammad , Muche Burkhard , T Tauer Josephine , S Kishnani Priya , Webersinke Gerald , Högler Wolfgang

Objectives: HPP is a multisystem disorder caused by ALPL variants that lead to ALP deficiency and excessive inorganic pyrophosphate, which inhibits mineralization of bones and teeth. A range of symptoms is associated with HPP inherited in an autosomal dominant manner that can manifest at any stage of life, making diagnosis difficult. The traditional method of classifying HPP into different types based on the onset of symptoms (prenatal benign, perinat...