A boy, aged 16 months, attended the hospital due to head and facial erythema for 15 months and vulva erythema for 10 months with aggravation for 5 days. The boy developed perioral and periocular erythema in the neonatal period and had erythema and papules with desquamation and erosion in the neck, armpit, and trigone of vulva in infancy. Blood gas analysis showed metabolic acidosis; the analysis of amino acid and acylcarnitine profiles for inherited metabolic diseases and the analysis of organic acid in urine suggested multiple carboxylase deficiency; genetic testing showed a homozygous mutation of c.1522C>T(p.R508W) in the HLCS gene. Finally the boy was diagnosed with holocarboxylase synthetase deficiency and achieved a good clinical outcome after oral biotin treatment. This article analyzes the clinical data of a child with holocarboxylase synthetase deficiency and summarizes the etiology, diagnosis, and treatment of this child, so as to provide ideas for clinicians to diagnose this rare disease.
男性患儿，16月龄，因发现头面部红斑15个月，外阴红斑10个月，加重5 d就诊。患儿新生儿期即出现口周、眼周红斑，婴儿期出现颈部、腋下、外阴三角区等腔口和皱褶部位的红斑、丘疹，可见脱屑和糜烂。血气分析提示代谢性酸中毒，血遗传代谢病氨基酸和酰基肉碱谱分析、尿液有机酸分析结果均提示多种羧化酶缺乏症，基因检测结果提示HLCS基因存在c.1522C>T(p.R508W)纯合突变。最终该患儿诊断为全羧化酶合成酶缺乏症，口服生物素治疗取得良好的临床疗效。该文总结了1例全羧化酶合成酶缺乏症患儿的临床资料，对其病因、诊断、治疗进行归纳总结，为临床医生诊断该类罕见疾病提供思路。.

BACKGROUND: Antifungal therapy has been claimed to be effective in polysymptomatic patients with diffuse symptoms from multiple body systems and even well defined diseases, traditionally not related to fungi. Hypersensitivity to fungus proteins and mycotoxins has been proposed as the cause.
METHODS: We conducted a 4-week randomized, double-blind, placebo-controlled study in 116 individuals selected by a 7-item questionnaire to determine whether the antifungal agent nystatin given orally was superior to placebo. At the onset of the study, the patients were free to select either their regular diet or a sugar- and yeast-free diet, which resulted in four different subgroups: nystatin + diet (ND); placebo + diet (PD); nystatin (N); and placebo (P).
RESULTS: Nystatin was significantly better than placebo in reduction of the overall symptom score (P < 0.003). In six of the 45 individually recorded symptoms, the improvement was significant (P < 0.01). All three active treatment groups reduced their overall symptom scores significantly (P < 0.0001), while the placebo regimen had no effect (P = 0.83). The benefit of diet was significant within both the nystatin (ND > N) and the placebo groups (PD > P).
CONCLUSIONS: Nystatin is superior to placebo in reducing localized and systemic symptoms in individuals with presumed fungus hypersensitivity as selected by a 7-item questionnaire. This superiority is probably enhanced even further by a sugar- and yeast-free diet.

Biotinidase, the enzyme responsible for recycling the vitamin biotin, is deficient in most individuals with late-onset multiple carboxylase deficiency. Based on clinical criteria, biotinidase deficiency appears to be inherited as an autosomal recessive trait; however, the inheritance of biotinidase serum activity as a quantitative trait has not been studied previously. In this study, both segregation analysis of proband families and the analysis of twin family data were used to determine the relative contributions of a major gene, polygenes and environment to the variation in serum biotinidase activity. Segregation analysis of 24 families of biotinidase-deficient individuals indicated that serum biotinidase activity is determined by the segregation of a single codominant major gene with the variability about the mean of each major genotype attributable to environmental effects. Significant polygenic effects could not be detected by this analysis. Variance component analysis of 128 twin families, which included the twins, their spouses, and their offspring, indicated that 70% of total variance in biotinidase activity is attributable to additive genetic effects, 22% to individual environmental effects, and 8% to shared environmental effects. The model also included an age effect for females. A portion (27%) of the estimated additive variance may be attributed to the segregation of the major gene. This study emphasizes the usefulness of studying multiple data sets representing different types of family relationships.

Biotinidase activity was determined in a pilot study of 78,000 dried blood samples on filter paper. In the assay the liberation of p-aminobenzoic-acid from biotinyl-p-aminobenzoic-acid by biotinidase is tested. One boy was identified to be with biotinidase deficiency. Transient reduction of biotinidase activity to virtually negative test results was observed in 8 preterm babies (recall: 0,01%). Specificity and sensitivity of the test were nearly 100%. We suggest that screening for biotinidase deficiency should be incorporated into existing neonatal screening programs for inborn errors of metabolism. This suggestion is based on the ease of testing, the necessity for presymptomatic laboratory diagnosis, and on the effectiveness of early treatment of the multiple carboxylase deficiency caused by defective biotinidase.