Refining the phenotype of SINO syndrome: A comprehensive cohort report of 14 novel cases.

BACKGROUND: SINO syndrome (Spastic paraplegia, Intellectual disability, Nystagmus and Obesity) is a rare autosomal dominant condition caused by heterozygous variants in KIDINS220. A total of 12 individuals are reported, comprising eight with SINO and four with an autosomal recessive condition attributed to bi-allelic KIDINS220 variants. METHODS: In our international cohort, we have comprised 14 individuals, carrying 13 novel pathogenic KIDINS220 variants in heterozygous form. We assessed clinical and molecular data of our cohort and previously reported individuals and based on functional experiments reached a better understanding of the pathogenesis behind KIDINS220-related disease. RESULTS: Using fetal tissue and in vitro assays, we demonstrate that the variants generate KIDINS220 truncated forms that mislocalize in punctate intracellular structures, with decreased levels of the full-length protein, suggesting a trans-dominant negative effect. 92% had their diagnosis within three years, with symptoms of developmental delay, spasticity, hypotonia, lack of eye contact and nystagmus. We identified a KIDINS220 variant associated with fetal hydrocephalus and show that 58% of examined individuals present brain ventricular dilatation. We extend the phenotypic spectrum of SINO syndrome to behavioral manifestations not previously highlighted. CONCLUSION: Our study provides further insights into the clinical spectrum, etiology and predicted functional impact of KIDINS220 variants.

Multicentric osteolysis with nodulosis and arthropathy (MONA) with cardiac malformation, mimicking polyarticular juvenile idiopathic arthritis: case report and literature review.

UNLABELLED: The 'vanishing bone' syndrome multicentric osteolysis with nodulosis and arthropathy (MONA) is a rare chronic skeleton disorder caused by matrix metalloproteinase 2 (MMP2) deficiency, mimicking erosive polyarticular juvenile idiopathic arthritis. MONA is characterised by facial dysmorphism, subcutaneous fibrocollagenous nodules, carpal and tarsal osteolysis and interphalangeal joint erosions. We present the case of a 5-year-old boy with double outlet right ventricle, ventricular septal defect, coarctation of the aorta and MONA. Previously, a total of 24 cases of MONA have been reported of which six also had congenital cardiac malformations. Despite treatment attempts of our patient with methotrexate, eternacept and prednisolone, serial X-ray studies documented continuous severe bone degeneration. CONCLUSION: The case documents the natural history of MONA and establishes a link between MMP2 deficiency and heart development, and given the recurring cardiac association, we suggest that all MONA patients be examined for possible cardiac defects.

[Visceral leishmaniasis in two children after vacation in Southern Europe]. / Visceral leishmaniasis hos to børn efter ferie i Sydeuropa.

Pancytopenia, fever and splenomegaly are frequent causes for referrals to paediatric haematology departments, on the suspicion of acute leukaemia. We report two cases of Danish children with the tropical disease visceral leishmaniasis (VL) contracted on short vacations in Southern Europe. One of the patients developed secondary haemophagocytic lymphohistocytosis (HLH). Both children were successfully treated with liposomal amphotericin B. In Denmark, VL is a rare but important differential diagnosis to acute leukaemia and HLH, and should be ruled out after journeys to endemic areas, including Southern Europe.