Abnormal fat distribution in two patients with RAB7A-associated Charcot-Marie-Tooth type 2B: a case report.

BACKGROUND

Charcot-Marie-Tooth disease type 2B (CMT2B) is an autosomal dominant neuropathy associated with pathogenic variants in the RAB7A gene, which encodes a GTPase involved in lysosomal and lipid metabolism. Although altered lipid metabolism has been observed in skin fibroblasts derived from patients with CMT2B, a clinical presentation with abnormal fat distribution has not been reported.

CASE PRESENTATION: We report two sisters with a confirmed pathogenic RAB7A variant (NM_004637.6:c.484G > A, (p.Val162Met)), who presented not only with classic CMT2B features but also with abnormal fat distribution, including excessive fat accumulation in the neck, upper back, and abdomen. Both patients underwent neurological evaluations, nerve conduction studies, and extensive endocrine workup, which ruled out other metabolic or endocrine causes. MRI confirmed atypical fat deposition. One patient underwent liposuction due to functional impairment with partial relief, but fat accumulation recurred.

CONCLUSION

Our case suggests that abnormal fat distribution may be a novel phenotypic feature in individuals with RAB7A-related CMT2B. Recognizing this manifestation may provide clinical insight into the lipid dysregulation and systemic effects in patients with CMT2B.