Splenial corpus callosum lesions in Boucher-Neuhäuser syndrome: a case series and comprehensive literature review with exploratory analysis of disease duration.

PURPOSE: Boucher-Neuhäuser syndrome (BNS) is a rare autosomal recessive neurodegenerative disorder caused by PNPLA6 variants, characterized by cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal degeneration. Although cerebellar atrophy is well documented, specific neuroimaging markers remain limited. We aimed to characterize magnetic resonance imaging findings, particularly corpus callosum abnormalities and their association with disease duration.

METHODS

We retrospectively analyzed brain MRI from four participants with BNS (two genetically confirmed, two clinically diagnosed) at our institution using 1.5T or 3T scanners with T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging sequences. A literature review identified 16 evaluable cases from 14 studies. Cases with multiple sequences were compared descriptively; exploratory Mann-Whitney U tests included single-sequence literature cases.

RESULTS

Cerebellar atrophy was universal (20/20, 100%). Splenial corpus callosum signal changes, manifesting as T2WI/FLAIR hyperintensity and/or T1WI hypointensity, were observed in 7/20 (35%) participants, though only 2 were confirmable across multiple sequences. Only 2 of 6 multisequence-evaluable cases met definite criteria; remaining positive literature-derived cases were classified as equivocal owing to single-sequence availability. One participant demonstrated restricted diffusion in corpus callosum lesions. Pituitary gland and stalk atrophy were identified in 6/20 (30%). Participants with corpus callosum abnormalities tended to have longer disease duration (median 25.0 vs. 15.0 years, p = 0.25). The triad-confirmed sensitivity analysis showed a similar trend without statistical significance.

CONCLUSION

Splenial signal abnormalities may be under-recognized findings in BNS, potentially associated with longer disease duration. Given the predominance of single-sequence images in the literature, this association remains exploratory and warrants confirmation in larger cohorts.