Quality of life of pediatric and adult individuals with osteogenesis imperfecta: a meta-analysis

Background Osteogenesis imperfecta (OI) is a group of rare inheritable disorders of connective tissue. The cardinal manifestations of OI are low bone mass and reduced bone mineral strength, leading to increased bone fragility and deformity that may lead to significant impairment in daily life. The phenotypic manifestations show a broad range of severity, ranging from mild or moderate to severe and lethal. The here presented meta-analysis aimed to analyze existing findings on quality of life (QoL) in children and adults with OI. Methods Nine databases were searched with predefined key words. The selection process was executed by two independent reviewers and was based on predetermined exclusion and inclusion criteria. The quality of each study was assessed using a risk of bias tool. Effect sizes were calculated as standardized mean differences. Between-study heterogeneity was calculated with the I$^{2}$ statistic. Results Among the studies included two featured children and adolescents (N = 189), and four adults (N = 760). Children with OI had significantly lower QoL on the Pediatric quality of life inventory (PedsQL) with regards to the total score, emotional, school, and social functioning compared to controls and norms. The data was not sufficient to calculate differences regarding OI-subtypes. In the adult sample assessed with Short Form Health Survey Questionnaire, 12 (SF-12) and 36 items (SF-36), all OI types showed significantly lower QoL levels across all physical component subscales compared to norms. The same pattern was found for the mental component subscales namely vitality, social functioning, and emotional role functioning. The mental health subscale was significantly lower for OI type I, but not for type III and IV. All of the included studies exhibited a low risk of bias. Conclusions QoL was significantly lower in children and adults with OI compared to norms and controls. Studies in adults comparing OI subtypes showed that the clinical severity of the phenotype is not related to worse mental health QoL. Future research is needed to examine QoL in children and adolescents in more sophisticated ways and to better understand the association between clinical severity of an OI-phenotype/severity and mental health in adults

Impact of kidney biopsy on deciding when to initiate enzyme replacement therapy in children with Fabry disease

BACKGROUND Recommendations on when to start enzyme replacement therapy (ERT) in children with Fabry disease (FD) differ between guidelines. In this study, kidney biopsies of a cohort of 14 untreated children and one treated child were analyzed for their morphologic changes to determine whether early initiation of ERT is indicated. METHODS All pediatric FD patients (< 18 years old) diagnosed between 2003 and 2021 in our department who received a kidney biopsy were enrolled. Clinical symptoms; laboratory parameters regarding kidney function, such as eGFR, plasma urea, protein-creatinine, and albumin/creatinine ratio; and 14 kidney biopsies prior to ERT and one under treatment were retrospectively analyzed. RESULTS A total of 14 patients were enrolled, including 9 male and 5 female children, aged 3-18 years (median age 11). Seven of the enrolled children were 10 years old or younger. Histological analysis of kidney biopsy samples revealed severe vacuolization and accumulation of inclusions in podocytes and renal tubules. The majority of cases had no FD-specific clinical or laboratory features independent of age, gender, or genotype. The youngest FD patient presenting with isolated abnormal kidney biopsy was 3 years old. CONCLUSIONS We demonstrate that histological lesions, typical for FD, can be observed in kidney biopsies at a very young age in patients without classical clinical symptoms or laboratory abnormalities. Thus, we recommend kidney biopsies as a possible tool for early diagnosis of renal involvement in FD. As a consequence of these early biopsy findings without a clinical correlate, an early initiation of ERT should be considered. A higher resolution version of the Graphical abstract is available as Supplementary information

Swiss national guideline for reimbursement of enzyme replacement therapy in late-onset Pompe disease.

Glycogen storage disease type II is a rare multi-systemic disorder characterised by an intracellular accumulation of glycogen due a mutation in the acid alpha glucosidase (GAA) gene. The level of residual enzyme activity, the genotype and other yet unknown factors account for the broad variation of the clinical phenotype. The classical infantile form is characterised by severe muscle hypotonia and cardiomyopathy leading to early death. The late-onset form presents as a limb girdle myopathy with or without pulmonary dysfunction. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) in infants is life saving. In contrast, therapeutic efficacy of rhGAA in the late-onset form is modest. High expenses of rhGAA, on-going infusions and poor pharmacokinetic efficacy raised a discussion of the cost effectiveness of ERT in late-onset Pompe disease in Switzerland. This discussion was triggered by a Swiss federal court ruling which confirmed the reluctance of a health care insurer not to reimburse treatment costs in a 67-year-old female suffering from Pompe disease. As a consequence of this judgement ERT was stopped by all insurance companies in late-onset Pompe patients in Switzerland regardless of their clinical condition. Subsequent negotiations lead to the release of a national guideline of the management of late-onset Pompe disease. Initiation and limitation of ERT is outlined in a national Pompe registry. Reimbursement criteria are defined and individual efficacy of ERT with rhGAA is continuously monitored

The novel missense mutation Met48Lys in FKBP22 changes its structure and functions.

Mutations in the FKBP14 gene encoding FKBP22 (FK506 Binding Protein 22 kDa) cause kyphoscoliotic Ehlers-Danlos Syndrome (kEDS). The first clinical report showed that a lack of FKBP22 protein due to mutations causing nonsense-mediated decay of the mRNA leads to a wide spectrum of clinical phenotypes including progressive kyphoscoliosis, joint hypermobility, hypotonia, hyperelastic skin, hearing loss and aortic rupture. Our previous work showed that these phenotypic features could be correlated with the functions of FKBP22, which preferentially binds to type III, VI and X collagens, but not to type I, II or V collagens. We also showed that FKBP22 catalyzed the folding of type III collagen through its prolyl isomerase activity and acted as a molecular chaperone for type III collagen. Recently, a novel missense mutation Met48Lys in FKBP22 was identified in a patient with kEDS. In this report, we expand the list of substrates of FKBP22 and also demonstrate that the Met48Lys mutation diminishes the activities of FKBP22, indicating that pathology can arise from absence of FKBP22, or partial loss of its function

Perturbations in fatty acid metabolism and collagen production infer pathogenicity of a novel MBTPS2 variant in Osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heritable and chronically debilitating skeletal dysplasia. Patients with OI typically present with reduced bone mass, tendency for recurrent fractures, short stature and bowing deformities of the long bones. Mutations causative of OI have been identified in over 20 genes involved in collagen folding, posttranslational modification and processing, and in bone mineralization and osteoblast development. In 2016, we described the first X-linked recessive form of OI caused by MBTPS2 missense variants in patients with moderate to severe phenotypes. MBTPS2 encodes site-2 protease, a Golgi transmembrane protein that activates membrane-tethered transcription factors. These transcription factors regulate genes involved in lipid metabolism, bone and cartilage development, and ER stress response. The interpretation of genetic variants in MBTPS2 is complicated by the gene’s pleiotropic properties; MBTPS2 variants can also cause the dermatological conditions Ichthyosis Follicularis, Atrichia and Photophobia (IFAP), Keratosis Follicularis Spinulosa Decalvans (KFSD) and Olmsted syndrome (OS) without skeletal abnormalities typical of OI. Using control and patient-derived fibroblasts, we previously identified gene expression signatures that distinguish MBTPS2-OI from MBTPS2-IFAP/KFSD and observed stronger suppression of genes involved in fatty acid metabolism in MBTPS2-OI than in MBTPS2-IFAP/KFSD; this was coupled with alterations in the relative abundance of fatty acids in MBTPS2-OI. Furthermore, we observed a reduction in collagen deposition in the extracellular matrix by MBTPS2-OI fibroblasts. Here, we extrapolate our observations in the molecular signature unique to MBTPS2-OI to infer the pathogenicity of a novel MBTPS2 c.516A>C (p.Glu172Asp) variant of unknown significance in a male proband. The pregnancy was terminated at gestational week 21 after ultrasound scans showed bowing of femurs and tibiae and shortening of long bones particularly of the lower extremity; these were further confirmed by autopsy. By performing transcriptional analyses, gas chromatography-tandem mass spectrometry-based quantification of fatty acids and immunocytochemistry on fibroblasts derived from the umbilical cord of the proband, we observed perturbations in fatty acid metabolism and collagen production similar to what we previously described in MBTPS2-OI. These findings support pathogenicity of the MBTPS2 variant p.Glu172Asp as OI-causative and highlights the value of extrapolating molecular signatures identified in multiomics studies to characterize novel genetic variants

CRIM-negative infantile Pompe disease: 42-month treatment outcome

Pompe disease is a rare lysosomal glycogen storage disorder characterized by deficiency of acid α-glucosidase enzyme (GAA) and caused by mutations in the GAA gene. Infantile-type Pompe disease is a multiorgan disorder presenting with cardiomyopathy, hypotonia, and muscular weakness, which is usually fatal. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) has recently been shown to be effective and subsequently yielded promising results in cross-reactive immunologic material (CRIM)-positive patients. CRIM-negative patients showed a limited response to ERT and died or were ventilator dependant. Over a period of 44months, we monitored cognitive and motor development, behavior, auditory function, and brain imaging of a CRIM-negative infantile Pompe disease patient on rhGAA and monoclonal anti-immunoglobulin E (anti-IgE) antibody (omalizumab) treatment due to severe allergic reaction. Cardiorespiratory and skeletal muscle response was significant, with almost normal motor development. Cognitive development—in particular, speech and language—deviated increasingly from normal age-appropriate development and was markedly delayed at 44months, unexplained by moderate sensorineural hearing impairment. Brain magnetic resonance imaging (MRI) at 18, 30, and 44months of age revealed symmetrical signal alteration of the deep white matter. Titer values of IgG antibodies to rhGAA always remained <1:800. The potential role of omalizumab in immune modulation remains to be elucidated; however, this is the first report presenting a ventilator-free survival of a CRIM-negative patient beyond the age of 36months. The central nervous system (CNS) findings are hypothesized to be part of a yet not fully described CNS phenotype in treated patients with longer surviva

Defect in proline synthesis: pyrroline-5-carboxylate reductase 1 deficiency leads to a complex clinical phenotype with collagen and elastin abnormalities

Pyrroline-5-carboxylate reductase 1 (PYCR1) catalyzes the last step in proline synthesis. Deficiency of PYCR1, caused by a defect in PYCR1, was recently described in patients with cutis laxa, intrauterine growth retardation, developmental dysplasia of the hips and mental retardation. In this paper, we describe additional six patients (ages ranging from 4 months to 55 years) from four Iranian families with clinical manifestations of a wrinkly skin disorder. All patients have distinct facial features comprising triangular face, loss of adipose tissue and thin pointed nose. Additional features are short stature, wrinkling over dorsum of hand and feet, visible veins over the chest and hyperextensible joints. Three of the patients from a large consanguineous family do not have mental retardation, while the remaining three patients from three unrelated families have mental and developmental delay. Mutation analysis revealed the presence of disease-causing variants in PYCR1, including a novel deletion of the entire PYCR1 gene in one family, and in each of the other patients the homozygous missense mutations c.616G > A (p.Gly206Arg), c.89T > A (p.Ile30Lys) and c.572G > A (p.Gly191Glu) respectively, the latter two of which are novel. Light- and electron microscopy investigations of skin biopsies showed smaller and fragmented elastic fibres, abnormal morphology of the mitochondria and their cristae, and slightly abnormal collagen fibril diameters with irregular outline and variable size. In conclusion, this study adds information on the natural course of PYCR1 deficiency and sheds light on the pathophysiology of this disorder. However, the exact pathogenesis of this new disorder and the role of proline in the development of the clinical phenotype remain to be fully explaine

Postprandial changes of amino acid and acylcarnitine concentrations in dried blood samples

Blood sampling for newborn screening cannot be standardized as for example blood collection in adults after an overnight fast. Therefore the influence of postprandial changes and individual variation is valuable information for the assessment of sensitivity and specificity of newborn screening for certain disorders. We have analyzed 92 pairs of dried blood samples taken pre- and one hour postprandially, respectively. We have determined the mean increase in metabolite concentration and calculated its significance. Individual variation after an overnight fast in healthy adults (n = 3) was between 12 and 32% (SD). Postprandial increases of acylcarnitines were mostly not significant and not exceeding 10%. Postprandial increase of amino acids was highly significant for most proteinogenic amino acids, but not for all. With the collected data we were able to estimate that mainly decreased levels of methionine and, to a lesser extent, of free carnitine could be "masked” by postprandial increases of the respective metabolites, and could therefore lead to false negative results for the detection of disorders of cobalamin metabolism and carnitine transporter deficienc

The PompeQoL questionnaire: Development and validation of a new measure for children and adolescents with Pompe disease

Genetic disorders pose great challenges for affected individuals and their families, as they must cope with the irreversible nature of the disease and a life‐long dependence on medical assistance and treatment. Children and adolescents dealing with Pompe disease (PD) often struggle to keep up with their peers in physical activities. To gain valuable insights into their subjective experiences and better understand their perception and coping related to daily challenges linked to their condition and treatment, the use of standardized questionnaires is crucial. This study introduces the novel PompeQoL 1.0 questionnaire for children and adolescents with PD, designed for comprehensive assessment of both disease‐specific FDH and HRQoL through self‐ and proxy reports. Content validity was ensured through patients' and parents' involvement at the initial stages of development and in subsequent cognitive debriefing process. Participants found the questionnaire easy to understand, answerable, relevant, and comprehensive. Adjustments based on feedback from patients and their parents improved its utility as a patient‐ and observer‐reported outcome measure. After careful item examination, 52 items were selected, demonstrating moderate to excellent test–retest reliability for most scales and initial evidence for satisfactory construct validity. The PompeQoL questionnaire stands as a valuable screening instrument for both clinical and research purposes. Future research should prioritize additional revisions and larger validation studies, focusing on testing the questionnaire in clinical practice and trials. Nevertheless, the PompeQoL 1.0 stands out as the first standardized measure providing insights into disease‐specific FDH and HRQoL among children and adolescents with various forms of PD

Phenotypic variability of the kyphoscoliotic type of Ehlers-Danlos syndrome (EDS VIA): clinical, molecular and biochemical delineation

BACKGROUND: The kyphoscoliotic type of Ehlers-Danlos syndrome (EDS VIA) (OMIM 225400) is a rare inheritable connective tissue disorder characterized by a deficiency of collagen lysyl hydroxylase 1 (LH1; EC 1.14.11.4) due to mutations in PLOD1. Biochemically this results in underhydroxylation of collagen lysyl residues and, hence, an abnormal pattern of lysyl pyridinoline (LP) and hydroxylysyl pyridinoline (HP) crosslinks excreted in the urine. Clinically the disorder is characterized by hypotonia and kyphoscoliosis at birth, joint hypermobility, and skin hyperelasticity and fragility. Severe hypotonia usually leads to delay in gross motor development, whereas cognitive development is reported to be normal. METHODS: We describe the clinical, biochemical and molecular characterisation, as well as electron microscopy findings of skin, in 15 patients newly diagnosed with this rare type of Ehlers-Danlos syndrome. RESULTS: Age at diagnosis ranged from 5 months to 27 years, with only 1/3 of the patients been diagnosed correctly in the first year of life. A similar disease frequency was found in females and males, however a broad disease severity spectrum (intra- and interfamilial), independent of molecular background or biochemical phenotype, was observed. Kyphoscoliosis, one of the main clinical features was not present at birth in 4 patients. Importantly we also noted the occurrence of vascular rupture antenatally and postnatally, as well as developmental delay in 5 patients. CONCLUSION: In view of these findings we propose that EDS VIA is a highly variable clinical entity, presenting with a broad clinical spectrum, which may also be associated with cognitive delay and an increased risk for vascular events. Genotype/phenotype association studies and additional molecular investigations in more extended EDS VIA populations will be necessary to further elucidate the cause of the variability of the disease severity