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Título

ATYPICAL CASE OF DUCHENNE DYSTROPHY WITH NEGATIVE DNA TESTS CASE REPORT

Apresentação do caso

Male, 11 years old, born by vaginal delivery, uneventful pregnancy, cried at birth with good sucking on the mother's breast. Parents without neurological diseases, consanguineous 3rd cousins. Falls and fatigue since the beginning of walking, in the 1st year of life. Evolved with difficulty in climbing stairs, running and jumping, pain in lower limbs with exercises. Appropriate weight and heig ht. Head support, speech onset, crawling and walking at 6, 7, 8 and 16 months, respectively. Delay in learning. Followup began in 2019 with a medullary biopsy that confirmed dystrophinopathy. Needed a wheelchair 2 years later. At the moment: not walking, does not maintain an upright posture even with support; normal head, neck, thorax, abdomen, spine, skin and genitalia; symmetrical lower and upper limbs with knee contractures and grade 4 strength in the proximal region (Medical Research Council of The Uni ted Kingdom. Echocardiograms (2017, 2020 and 2021): no changes, EF 72%, 70% and 60%, respectively; exams Laboratory tests (2017): blood count, urea, creatinine, 25OHVitamin D, TSH and free T4, within normal ranges; DHL 1,440 / CPK 8470 / CK MB 95 / AST 462 / ALT 640; Laboratory tests (2018) blood count, urea, creatinine , 25OHVitamin D, TSH, free T4, sodium, potassium, magnesium, calcium and phosphorus within normal ranges; DHL 724 / CPK 4528 / CK MB 72; Molecular DNA analysis (2019) for DMD gene –- MLPA, NG S, ANO5 , DYSF, GAA, SGCA, SGCB, SGCD, SGCG, APN3, FKRP, TCAP: absence of pathogenic variants; Exome Sequencing NGS (2019): no variants justifying the clinical picture; Immunohistochemical molecular biopsy (2019): significant reduction of DYS2 and DYS3 e xpression with diffuse sarcolemmal and utrophin expression (autosomal dystrophin analogue, focal reduction of gammaWestern Blot (2019): Cterminal and Nsarcoglycan that may be secondary; terminal dystrophin absent bands compatible with dystrophinopathy.

Discussão

The report exposes an atypical case of Duchenne Muscular Dystrophy (DMD) with expected clinical findings, but with DNA analyzes that did not confirm the diagnosis, being necessary to correlate molecular biopsy and Western Blot.

Comentários finais

There are few cases in the literature of falsenegative DNA analyzes for DMD. The case is part of the context of valuing clinical findings and anamnesis in addition to specialized and robust tests for the diagnosis of rare diseases, among them: dystrophino pathies

Palavras Chave

Duchenne Dystrophy; Dystrophinopathy; DNA analysis

Declaração de conflito de interesses de TODOS os autores

Declaramos não ter conflito de interesses.