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 |