RESUMEN
Mitochondrial disorders (MIDs) are a heterogeneous group of genetic metabolic diseases due to mutations in the mitochondrial DNA (mtDNA) or in the nuclear DNA (nDNA) (Rahman and Rahman, 2018). Some affected genes encode proteins with various functions, or structural RNAs such as transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs). MIDs may also be caused by mutations in non-coding regions (e.g., D-loop of mtDNA) (Rahman and Rahman, 2018). Proteins involved in MIDs include enzymes, assembling factors, transport proteins, signaling proteins, pore proteins, and fusion/fission proteins (Gorman et al., 2016). The pathways most frequently affected by mutations in "mitochondrial genes" are the respiratory chain and the oxidative phosphorylation. Dysfunction of many other pathways (e.g., β-oxidation, pyruvate-dehydrogenase complex, and heme synthesis) may also manifest as MIDs (Hu et al., 2019). The estimated prevalence of MIDs is at least 1:5000 (Ng and Turnbull, 2016).
RESUMEN
Erdheim–Chester disease (ECD) is a rare, non-inherited, non- Langerhans form of histiocytosis of unknown origin, first described in 1930. This entity is defined by a mononuclear infiltrate consisting of lipid laden, foamy histiocytes that stain positively for CD68. Individuals affected by this disease are typically adults between their 4th and 6th decades of life. The multi systemic form of ECD is associated with significant morbidity, which may arise due to histiocytic infiltration of critical organ systems. Among the more common sites of involvement are the skeleton, central nervous system, cardiovascular system, lungs, kidneys (retroperitoneum) and skin. The most common presenting symptom of ECD is bone pain. Bilateral symmetric increased tracer uptake on 99mTc bone scintigraphy affecting the periarticular regions of the long bones is highly suggestive of ECD. However, definite diagnosis of ECD is established only once CD68(+), CD1a(−) histiocytes are identified within a biopsy specimen with aid of clinical and radiological data. Here we present a rare case of Erdheim-Chester disease in a 46 year male patient based on clinical data, radiological data, histopathological and immunohistochemistry findings.
RESUMEN
Background: Recurrent facial palsy in a patient merits investigation for underlying etiology.Case characteristics: 8-year-old boy with erythematous itchy skin lesion and recurrentfacial palsy. Observation: He had a past history of aseptic meningitis andnephrocalcinosis. Raised angiotensin converting enzyme levels, interstitial lung disease onCT chest, and non caseating granulomas on skin biopsy clinched the diagnosis ofsarcoidosis. Message: Multisystem involvement and recurrent lower motor facial nervepalsy is a clinical clue for sarcoidosis.