absent pupillary reflex

Brown-Vialetto-Van Laere Syndrome 2

Clinical Characteristics
Ocular Features: 

Decreased vision, optic atrophy, and nystagmus are frequently present.  Pupillary reflexes may be absent.

Systemic Features: 

Rapidly progressive muscle weakness and ataxia present in childhood.  Early development may be normal but the first symptoms usually appear by age 2 or 3 years of age.  Cognition is usually normal.  Exercise intolerance soon appears along with dysphonia, dyspnea, dysphagia, and weakness of shoulder, neck and axial muscles.  Wasting and weakness of hand muscles is often noticeable.  Kyphoscoliosis, tongue fasciculations, and areflexia are often seen.  Sensorineural hearing loss is a common feature.

Death from respiratory insufficiency often occurs within a few years after onset.

Genetics

Homozygous mutations in the SLC52A2 (8q24.3) gene have been identified in patients with this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Administration of riboflavin has been reported to be beneficial in lessening symptoms.

References
Article Title: 

SLC52A2 mutations cause SCABD2 phenotype: A second report

Babanejad M, Adeli OA, Nikzat N, Beheshtian M, Azarafra H, Sadeghnia F, Mohseni M, Najmabadi H, Kahrizi K. SLC52A2 mutations cause SCABD2 phenotype: A second report. Int J Pediatr Otorhinolaryngol. 2018 Jan;104:195-199.

PubMed ID: 
29287867

Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2

Foley AR, Menezes MP, Pandraud A, Gonzalez MA, Al-Odaib A, Abrams AJ, Sugano K, Yonezawa A, Manzur AY, Burns J, Hughes I, McCullagh BG, Jungbluth H, Lim MJ, Lin JP, Megarbane A, Urtizberea JA, Shah AH, Antony J, Webster R, Broomfield A, Ng J, Mathew AA, O'Byrne JJ, Forman E, Scoto M, Prasad M, O'Brien K, Olpin S, Oppenheim M, Hargreaves I, Land JM, Wang MX, Carpenter K, Horvath R, Straub V, Lek M, Gold W, Farrell MO, Brandner S, Phadke R, Matsubara K, McGarvey ML, Scherer SS, Baxter PS, King MD, Clayton P, Rahman S, Reilly MM, Ouvrier RA, Christodoulou J, Zuchner S, Muntoni F, Houlden H. Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2. Brain. 2014 Jan;137(Pt 1):44-56.

PubMed ID: 
24253200
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