What is the incidence of biotin deficiency in preschool children with global developmental delay?
| Study | Study group | Study type (level of evidence) | Outcome | Key result | Comments |
|---|---|---|---|---|---|
| Sutherland et al6 | 274 Children with low IQ, seizures, hearing loss, ataxia or motor disorder in a large outpatient clinic over a 4-year period | Prospective cohort (level 4) | Prevalence of BTD | None (95% CI 0 to 3.6) of the patients had BTD | Sample size is too small to detect BTD in the general population (95% CI 0 to 6/60 089) |
| Marrero- Gonzalez et al13 | 55 patients with MR of unspecific origin born within the period 1977–1997 | Prospective cohort (level 4) | Prevalence of BTD | None (95% CI 0 to 3.6) of the patients had evidence of BTD | Sample size is too small to detect BTD in general population (95% CI 0 to 6/60 089) |
| Zhang et al8 | 155 children with developmental delay from various brain disorders | Prospective cohort (level 4) | Prevalence of BTD and inborn metabolic errors | 11/158 (7%) had inborn metabolic errors, 1/158 had BTD | Prevalence of BTD in children with MR from brain disorders is higher than in the general population |
BTD, biotinidase deficiency; MR, mental retardation.