There is an emerging body of evidence showing that young patients, post haematopoietic stem cell transplantation (HSCT), can develop skeletal changes that mimic an osteochondrodysplasia process. The key discriminator is that these children have had otherwise normal growth and skeletal development before the therapeutic intervention (HSCT), typically for a haematological malignancy. Herein we present that case of a boy who underwent HSCT for Haemophagocytic Lymphohistiocytosis (HLH) aged 2 years. Following Intervention with HSCT this boy\'s growth has severely decelerated (stature less than 1st centile matched for age) and he has developed a spondyloepiphyseal dysplasia.

Objective: Behavioral variant frontotemporal dementia (bvFTD) is a neurodegenerative condition characterized by progressive changes in behavior, cognition, and day-to-day functioning. Progression of the disease usually leads to death 3-5 years after diagnosis. However, there are reports of individuals who are initially diagnosed with bvFTD but fail to progress. These individuals are thought to have what is becoming known as phenocopy bvFTD (phFTD). Methods: This manuscript reviews a single case study of a 68-year-old male Veteran who was diagnosed with bvFTD in 2010, which has not progressed over time. Results: Review of serial neuropsychological evaluations was broadly normal with mild evidence of executive dysfunction with minimal reliable change in his performances from 2015, 2017, and 2022 evaluations. He also has not developed neuroimaging evidence of FTD. Conclusions: This case illustrates the importance of monitoring individuals over time and incorporating neuroimaging data into the diagnosis. We believe this Veteran\'s presentation is most consistent with what has been described as phFTD.

UNASSIGNED: Danon disease (DD) is a rare X-linked disorder due to mutations in the lysosome-associated membrane protein 2 gene. It is characterized by a clinical triad of hypertrophic cardiomyopathy, skeletal myopathy, and a variable degree of intellectual disability.
UNASSIGNED: In this case series, we describe a mother and her son affected by DD, highlighting consistent clinical severity despite the expected variability related to gender. The mother (Case 1) presented isolated cardiac involvement, with an arrhythmogenic phenotype that evolved into severe heart failure requiring heart transplantation (HT). Danon disease was diagnosed 1 year after this event. Her son (Case 2) showed an earlier age onset of symptoms with complete atrioventricular block and fast progression of cardiac disease. Diagnosis was established 2 years after clinical presentation. He is currently listed for HT.
UNASSIGNED: In both of our patients, diagnostic delay was extremely long and could have been avoided by emphasizing the relevant clinical red flags. Patients affected by DD may present clinical heterogeneity in terms of natural history, age of onset, and cardiac and extracardiac involvement, even in the same family. Early diagnosis that phenotypic sex differences may impact is a crucial factor in managing patients with DD. Considering the rapid progression of cardiac disease and the poor prognosis, early diagnosis is important and close surveillance should be mandatory during follow-up.

Danon disease (OMIM 300257) is an X-linked lysosomal storage disorder, characterized by hypertrophic cardiomyopathy (HCM), skeletal myopathy, variable intellectual disability, and other minor clinical features. This condition accounts for ~ 4% of HCM patients, with a more severe and early onset phenotype in males, causing sudden cardiac death (SCD) in the first three decades of life. Genetic alterations in the LAMP2 gene are the main cause of this inherited fatal condition. Up to date, more than 100 different pathogenic variants have been reported in the literature. However, the majority of cases are misdiagnosed as HCM or have a delay in the diagnosis.
Here, we describe a young boy with an early diagnosis of HCM. After 2 episodes of ventricular fibrillation within 2 years, genetic testing identified a novel LAMP2 pathogenic variant. Subsequently, further clinical evaluations showing muscle weakness and mild intellectual disability confirmed the diagnosis of Danon disease.
This report highlights the role of genetic testing in the rapid diagnosis of Danon disease, underscoring the need to routinely consider the inclusion of LAMP2 gene in the genetic screening for HCM, since an early diagnosis of Danon disease in patients with a phenotype mimicking HCM is essential to plan appropriate treatment, ie cardiac transplantation.