Atypical Presentation of Tangier Disease-Expanding the Clinical Spectrum.

Abstract: Tangier disease is an autosomal recessive multisystem metabolic disorder with neuromuscular manifestations including peripheral neuropathy such as multifocal mononeuropathy or pseudosyringomyelia patterns. We report a novel phenotype of Tangier disease with predominant anterior horn cell involvement. A 16-year-old adolescent girl born to consanguineous parents had a 1-year history of hip girdle weakness with waddling gait and progressive atrophy of the right leg. She had orange tonsils, prominent lingual tonsils, soft skin, distal joint laxity, diffuse hypotonia with asymmetric wasting of legs, proximodistal moderate weakness in lower limbs, and tendon reflexes were hypoactive. The creatine kinase level was 70 U/L. Serum showed an abnormally low level of high- and low-density lipoprotein. Whole-exome sequencing showed a novel likely pathogenic splice site homozygous mutation c.2542+1G > A in the ABCA1 gene at intron 17. Hence, a high degree of suspicion and search for peripheral clinical markers is needed in patients with unusual anterior horn cell syndromes.