ICNC Abstracts, ICNC 2018

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Clinical profile and benefit from riboflavin in BVVL due to RFVT2 deficiency
Manoj Peter Menezes, Kayla Cornett, Gabrielle Donlevy, Joshua Burns

Last modified: 2018-09-09

Abstract


Brown-Vialetto-Van Laere (BVVL) syndrome is a progressive inherited peripheral neuropathy due to mutations in the genes encoding the riboflavin transporters RFVT2 and RFVT3.  Recognising the unique clinical profile of RFVT2 deficiency enables early institution of high-dose riboflavin therapy. We characterised the clinical profile and CMT Paediatric Scale (CMTPedS) assessments of 10 children with RFVT2 deficiency. 7 individuals had homozygous partial loss-of-function G306R mutations in SLC52A2 (which encodes RFVT2). They presented between the ages of 3 and 8 years with gait ataxia and hearing loss. The other 3 children were compound heterozygous with at least one complete loss of function mutation, and presented in the first 2 years of life, two children presenting with nystagmus and motor regression. With disease progression, upper limb predominant 'child-in-the-barrel' weakness, bulbar weakness and respiratory failure were seen. The baseline CMTPedS score was 25.3+9.3 points (n=7) and was highly correlated with age, showing an age-related progression of 2.1 points/year. All affected individuals were treated with high-dose riboflavin (50mg/kg, max 2g). Younger individuals showed improvement with their motor skills and recent onset hearing loss was reversed. Older children remained stable. On medication, the median progression over one year was 1.0+2.2 points. Recognising the early markers of BVVL due to RFVT2 deficiency is important, as early diagnosis enables institution of riboflavin therapy at an age where it is likely to be most effective. Treated children continue to progress slowly, and ongoing efforts to understand the pathophysiology of this disorder and develop other disease-modifying therapies remain important.


Keywords


BVVL, RTD, Riboflavin,

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