Developmental and behavioral outcomes of preschool-aged children with biotinidase deficiency identified by newborn screening.

Biotinidase deficiency (BD) may cause neurological symptoms and developmental problems. However, newborn screening of BD and early biotin treatment prevent the manifestation of the majority of symptoms. This study intended to examine the developmental and behavioral outcomes as well as maternal anxiety and depressive symptoms of preschool-aged children with BD and to compare these with the outcomes of healthy preschool-aged children. In total, 49 children with BD and 23 healthy children are included. All children were screened for developmental and behavioral problems. Moreover anxiety and depressive symptomatology of their mothers were evaluated. Despite the high percentage of developmental delay in BD group, the numbers of children screened positive for a developmental delay were statistically similar in children with BD and healthy children. Among patients with BD, children with risk of developmental delay had more unfavorable socio-demographic features compared to typically developing ones. Behavioral problem scores, maternal anxiety, and depressive symptoms scores of children with BD were not higher than the healthy children.Conclusion: Children with BD were not different from their healthy peers in terms of developmental and behavioral outcomes. Developmental problems of children with BD may be related to the unfavorable socio-demographic features, not the BD itself. What is known: • Biotinidase deficiency (BD) may result in neurological symptoms and developmental problems. • Newborn screening and early biotin supplementation prevent the manifestation of the majority of symptoms. What is new: • Preschool-aged children with BD identified by newborn screening are not different from their healthy peers in terms of developmental and behavioral outcomes. • Maternal anxiety and depressive symptoms scores of children with BD are similar to scores of healthy children.

Biotin deficiency in hyperemesis gravidarum.

The aim of this study was to determine the serum biotin levels in patients with hyperemesis gravidarum (HG). Ninety pregnant women with HG (mild (n = 30), moderate (n = 30) and severe (n = 30)), and 80 pregnant women without HG were included for this study. In both groups, serum biotin levels were measured. There were no statistically significant differences in demographic and clinical characteristics between the HG groups and the control group except for PUQE scores. Serum biotin levels in all hyperemesis gravidarum groups were statistically significantly lower than control group. Negative statistically significant correlation between hyperemesis gravidarum severity and serum biotin levels was noted. This is the first study that shows low serum biotin levels in women with hyperemesis gravidarum. Impact statement What is already known on this subject? Almost 80% of pregnant women have nausea and vomiting. If nausea and vomiting became severe and the symptoms combined with weight loss and ketonuria; the diagnosis should be hyperemesis gravidarum (HG). The etiopathogenetic factors of this unwanted condition have not been exactly known. Biotin is an essential water-soluble vitamin. Biotin catabolism increases in pregnancy. Marginal biotin deficiency occurs in approximately 50% of the gestations despite the "normal" biotin intake on the diet. What do the results of this study add? Current study results elucidated that serum biotin levels were lower in HG cases compared to non HG cases. This study is the first study that reports the association between low serum level of biotin and HG. What are the implications of these findings for clinical practice and/or further research? Further research is needed to show the importance of biotin supplementation in women with hyperemesis gravidarum.

High incidence of partial biotinidase deficiency cases in newborns of Greek origin.

Biotinidase deficiency (BTD) is an inherited disorder with severe clinical manifestations if not treated early. 63,119 neonates were tested for BTD according to a 3-step protocol. Biotinidase activity was initially estimated through standard colorimetric method on dried blood spots, then the suspected samples were subjected to molecular analysis of the BT gene and determination of BT activity in serum through an HPLC method. 14 infants with partial BTD (incidence 1:4508) were detected. Nine of them were homozygotes (D444H/D444H), and 4 compound heterozygotes carrying D444H combined with Q456H, T532M, C186Y and R157H, respectively. All were asymptomatic and supplemented with 10mg biotin. Although the number of screened neonates is rather small, it may be suggested that the incidence of the partial BTD infants is the highest ever reported. Detection of BTD should be added to the Greek national neonatal screening program.

Profound biotinidase deficiency: a rare disease among native Swedes.

Biotinidase deficiency is an autosomal recessive metabolic disorder included in many newborn screening programmes. Prior to the introduction of screening for biotinidase deficiency in Sweden in 2002, the disorder was almost unknown, with only one case diagnosed clinically. Biotinidase activity was measured in dried blood spots with a semiquantitative method using biotin-6-amidoquinoline as substrate. The cutoff value was set at 25% (later lowered to 20%) of the mean activity of all samples measured on that day. The disorder was confirmed by quantitative determination of biotinidase activity in plasma and DNA analyses. Over a period of 6 years, 13 patients were identified among 637,452 screened newborns and 5,068 adoptive/immigrant children. None of the patients had clinical symptoms at the time of diagnosis. Six patients had profound biotinidase deficiency, with an activity of 0-5% of normal in plasma. Four of these patients were born to parents who were first cousins of Middle Eastern or African origin. Eighteen gene alterations were identified, nine of which have not previously been described: seven mutations p.L83S (c.248T > C), p.R148H (c.443G > A), p.N202I (c.605A > T), p.I255T (c.764T > C), p.N402S (c.1205A > G), p.L405P (c.1214T > C), p.G445R (c.1333G > A) and two silent mutations p.L71L (c.211C > T) and p.L215L (c.645C > T). The predicted severity of the novel mutations was analyzed by sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), predicting p.L83S, p.L405P and p.G445R as severe mutations. Due to the high rate of immigrants since 1990 from non-Nordic countries, the incidence of biotinidase deficiency is similar to that found in many other Western countries.

Outcome in patients with profound biotinidase deficiency: relevance of newborn screening.

Profound biotinidase deficiency (PBD) is an autosomal recessively inherited disorder of biotin metabolism, which can be detected by newborn screening and treated with biotin supplementation. Children were investigated in whom PBD was detected by newborn screening and who were treated presymptomatically, or who were not screened but were diagnosed and treated after experiencing initial clinical symptoms (symptomatic children). In a follow-up of our study group, differences in development, social and behavioural adaptation, and signs of residual impairment were examined. Parents and physicians of children with PBD completed questionnaires which included the Child Behavior Checklist and Vineland Adaptive Behavior Scales. Information was obtained for 37 children (24 males, 13 females; median age at recruitment 6 years 8 months, range to 6 months-20 years; median length of follow-up 6 years 6 months, range 5 months to 18 years 3 months). All 11 symptomatic children had residual enzyme activity of <1%, or variants of the Michaelis-Menten constant which were not detected by newborn screening. Some symptomatic children showed residual impairments: hearing impairment (n=2), optic atrophy (n=2), both hearing impairment and optic atrophy (n=2). In addition, symptomatic children had a higher risk of delayed motor and speech development. No child with PBD detected by newborn screening (n=25) had auditory or visual loss; and milestones of speech development and motor skills were reached at an appropriate age. There was no significant difference in social adaptation or behavioural problems between symptomatic and asymptomatic children. Symptomatic children often have developmental delay and are at risk of irreversible damage to auditory, visual, or central nervous functions; whereas children with PBD (established presymptomatically following newborn screening) treated with biotin supplementation, do not experience these effects.