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Table 1 Finding in patients with biotinidase deficiency

From: Genotypic and phenotypic correlations of biotinidase deficiency in the Chinese population

Patient 1 2 3 4 5 6
Diagnosed by Clinical Clinical Clinical Newborn screen Newborn screen Newborn screen
Biotinidase activity (nmol/min/dL) (% of control mean) 12.5 (7.8%) 15.4 (9.8%) NA 36.5 (23%) 36.3 (23%) 32.5 (20%)
C5OH at newborn screening (μM) NA 0.17 NA 0.14 0.10 0.12
C5OH at presentation (μM) 3.5 3.37 0.362
BTD mutations c.460-1G > A/c.1382 T > C (p.V461D) c.460-1G > A/c.1382 T > C (p.V461D) c.1384delA (p.R462Gfs) homozygous c.1250_1251TC > AG (p.V417E)/c.1306G > A (p.E436K) c.1361A > G (p.Y454C)/c.1306G > A (p.E436K) c.1250_1251TC > AG (p.V417E)*
Urine GCMS Elevation of 3-hydroxyisovalerate, 3-methylcrotonylglycine, lactate, pyruvate Elevation of 3-hydroxyisovaleric acid Elevation of 3-hydroxyisovaleric acid NA NA No specific finding
Seizure onset age 3 m 3 m 2 m
Respiratory problems Apnea requiring BiPAP at night Laryngomalacia
Hearing loss + +
Optic atrophy + NA
Eczema + + NA
Alopecia
Candidiasis Diaper rash NA
Current status 10y, developmental delay 3y, normal development Expired at 2y, developmental delay 5 m, asymptomatic 1 m, asymptomatic NA
  1. NA: not available, C5OH normal < 0.182 μM, *one allele deletion cannot be excluded