Impact of clinical symptoms on quality of life in adult hypophosphatasia: a monocentric study in northern Germany

Adult hypophosphatasia (HPP) is caused by genetic variations in the <i>ALPL</i> gene causing a loss-of-function, leading to disruptions in normal skeletal mineralization processes. However, the impact of adult HPP extends beyond the skeletal system, as the ubiquitous expression and involvement of the affected enzyme in the body's metabolic processes result in a broad spectrum of symptoms. Consequently, individuals with HPP mostly experience a diminished quality of life (QoL). The severity and presentation of the disease are highly heterogeneous. Despite this variability, the underlying reasons and contributing factors remain poorly understood. This study aims to get a better understanding of HPP patients QoL and identify parameters that correlate with their QoL. To address this, our study retrospectively analyzed 146 adult patients diagnosed with HPP. Health-related quality of life was assessed using the Short Form Health Survey version 1.0 (SF-36 v1), and pain levels were assessed using the brief pain inventory. Our findings indicate that HPP compromises not only physical health but also significantly impacts mental well-being, with a Physical Component Summary of 39.9 and a Mental Component Summary of 39.3. Moreover, we observed that patients' QoL was inversely associated with factors such as obesity, lower concentrations of alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BAP). Additionally, indicators of physical status demonstrated a strong correlation with QoL. These results underscore the need for a systematic approach to monitoring both somatic parameters and mental health in adult HPP patients to help evaluate disease progression, treatment effects, and overall patient condition. Clinicians can utilize objective criteria, namely physical status indicators, ALP and BAP concentrations, and BW as additional tools in assessing patients' conditions, as these factors are linked to QoL in HPP. This may help clinicians estimate patients disease status and may help to assess and monitor the impact of therapy on QoL.