Biotinidase Deficiency Research Articles

Investigation of the Effects of Biotinidase Deficiency on Plasma Cholinesterase Activity

Purpose: Biotinidase deficiency (BD) is a rare autosomal recessive metabolic disorder that impairs the body's ability to recycle biotin, a crucial coenzyme for carboxylase enzymes involved in various metabolic processes. This study aims to evaluate the effects of biotinidase deficiency on cholinesterase activity in plasma, hypothesizing that the metabolic disruptions caused by inadequate biotin recycling may lead to alterations in cholinesterase function. Materials and methods: Plasma samples were collected from 73 individuals categorized into four genetic groups: wild type (n = 12), heterozygous (n = 30), homozygous (n = 19), and compound heterozygous (n = 12). Cholinesterase activity was measured using a colorimetric method. Results: The study discovered that the cholinesterase activity of the Heterozygous group was higher than the homozygous group (p = 0.0356). Additionally, cholinesterase activity was significantly lower in homozygous and compound heterozygous people than in wild and heterozygous groups (p = 0.0272). The statistically significant changes suggested a relationship between biotinidase deficiency and altered cholinergic activity. Conclusion: The findings indicate that biotinidase deficiency, particularly in its severe variants, may cause considerable reductions in cholinesterase activity, contributing to the neurological symptoms found in affected patients. More studies are needed to investigate the processes behind this association and develop strategies for reducing the effects of BD on cholinesterase activity and neurological health.

Comprehensive analysis of genotypic and phenotypic characteristics of biotinidase deficiency patients in the eastern region of Türkiye

Background. Biotin is a water-soluble vitamin that plays a key role in carboxylation. The formation of free biotin is impaired in biotinidase deficiency (BD), resulting in impaired biotin-dependent carboxylase functions. Based on the percentage of residual serum enzyme activity, BD is classified as partial and profound. Methods. Retrospective data including gender, age, parental consanguinity, family history, biotinidase activity analyses, type of deficiency (partial-profound), physical examination, treatment, and genotypes were evaluated in patients diagnosed with biotinidase deficiency in a single center in the eastern region of Türkiye. Patients whose biotinidase enzyme activity was below 30% with biallelic variants in the BTD gene were diagnosed as BD. Results. A total of 302 patients were included in the study. Parental consanguinity was present in 135 (44.7%) of them. Two hundred eighty-six (94.7%) were diagnosed by neonatal screening, 14 (4.6%) by family screening and two (0.06%) by clinical symptoms. Ninety-two (30.5%) of the patients were followed-up with profound deficiency and 210 (69.5%) with partial deficiency. A total of 306 variants were detected. Twenty different variants (3 novel - 3 rare) and 31 different genotypes were detected. The 3 most frequently detected variants were c.410G>A (p.Arg137His; 47.3%), c.1270G>C (p.Asp424His; 29.7%), and c.38_44delGCGGCTGinsTCC (p.Cys13Phefs*36; 15.3%). The 3 most frequently identified genotypes were c.410G>A (p.Arg137His) / c.1270G>C (p.Asp424His) compound heterozygous (32.4%), c.410G>A (p.Arg137His) homozygous (24.8%), and c.38_44delGCGGCTGinsTCC (p.Cys13Phefs*36) / c.1270G>C (p.Asp424His) compound heterozygous (12.2%). Patients with c.410G>A (p.Arg137His) homozygous variant, c.38_44delGCGGCTGinsTCC (p.Cys13Phefs*36) homozygous variant and c.38_44delGCGGCTGinsTCC (p.Cys13Phefs*36) / c.410G>A (p.Arg137His) compound heterozygous variant were statistically significantly associated with profound deficiency. Compound heterozygosity of c.410G>A (p.Arg137His) / c.1270G>C (p.Asp424His) variants were significantly associated with partial deficiency. Conclusions. The association between the BTD genotype and biochemical phenotype is not always consistent. Our study provides valuable data by adding variants with genotype-phenotype correlations to the literature and three novel variants, which can provide significant guidance in clinical follow-up.

Biotinidase Deficiency and Aplasia Cutis Congenita with Ecterodactyly Syndrome (ACCES) in a case of Moya Moya Disease: A Missing Link

Biotinidase Deficiency (BD) is a rare autosomal recessive disorder caused by mutations in the BTD gene, leading to impaired biotin recycling and disruption in energy metabolism, oxidative stress, and blood-brain barrier function. This condition increases the risk of neurovascular events such as strokes. In parallel, the UBA2 gene's loss of function, through various mutations, results in Aplasia Cutis Congenita with Ectrodactyly (ACCES) syndrome, an autosomal dominant disorder with highly variable expressivity. ACCES syndrome commonly presents with scalp defects and less frequently with ectrodactyly, alongside other subtle skeletal anomalies, early growth deficiency, and neurodevelopmental delay. This case report discusses a 6-year-old child presenting with an acute stroke and distinct dysmorphic features, highlighting a rare association between Biotinidase Deficiency and ACCES syndrome, which likely contributed to the development of Moya Moya Disease (MMD), a rare progressive cerebrovascular disorder. The case suggests that the combination of neurovascular stress due to both BD and ACCES may increase the risk of stroke and MMD in affected individuals. This underscores the importance of recognizing overlapping genetic conditions that could lead to severe neurovascular complications.

A retrospective study on biotinidase deficiency: analysis of the Eastern Anatolia region patient cohort

ABTRACT This study retrospectively reviews individuals diagnosed with biotinidase deficiency in Eastern Anatolia to analyze the genetic variants and their relationship with biotinidase activity levels. The research focuses on determining the percentage impact of different variants on enzyme activity. The study included 357 patients who presented to Erzurum City Hospital with symptoms of biotinidase deficiency between 2018 and 2023 and were referred to the medical genetics department. Biotinidase enzyme levels were determined using spectrophotometric and colorimetric techniques, while Sanger sequencing analyzed the four exons and intron boundaries of the BTD gene. In the analysis of 357 patients (181 boys, 176 girls), the most frequent variant was c.1270G > C | p.Asp424His. Biotinidase enzyme activity was above 30% in 97.3% of patients with a homozygous p.D424His mutation. The mutations that caused the most significant decrease in enzyme activity were c.410G > A p.Arg137His, c.38_delinsTCC p.Cys13phefs*36, and c.1535C > T p.Thr512Met. Hearing loss (4 patients) and optic atrophy (1 patient) were mainly observed in patients with the c.38_delinsTCC mutation (homozygous or heterozygous). Most patients were asymptomatic, and mild symptoms were effectively prevented with biotin treatment. This study provides a detailed analysis of genetic diversity and clinical presentation in biotinidase deficiency cases in Eastern Anatolia, demonstrating the efficacy of biotin treatment. It highlights the significant role of genetic variants in phenotypic diversity and the need for personalized treatment, calling for further genetic research to enhance understanding of variant diversity and its impact on enzyme activity.

Urine organic acid metabolomic profiling by gas chromatography mass spectrometry: Assessment of solvent extract evaporation parameters on the recovery of key diagnostic metabolites

BackgroundAnalysis of urinary organic acids (UOAs) by gas chromatography mass-spectrometry (GC–MS) is widely used in metabolomic studies. It is a complex test with many limitations and pitfalls yet there is limited evidence in the literature to support best practice. This study investigated the impact of drying down time and temperature on the recovery of 16 key analytes from solvent extracts. MethodsPooled urine specimens were enriched with organic acids. Urine aliquots (n = 3) were acidified and extracted into diethyl ether and ethyl acetate. Extracts were dried under nitrogen at ambient temperature (25 °C); 40 °C; 60 °C then left for 0; +5; +15 min. Dried extracts were derivatised with N,O,-bis-(trimethylsilyl)trifluoroacetamide prior to analysis by GC–MS. Urine specimens from individuals with biotinidase deficiency, maple syrup urine disease (MSUD) and ketotic hypoglycemia were analysed to demonstrate the potential clinical impact. ResultsRecovery of shorter chain hydroxycarboxylic acids decreased significantly when extracts were dried above 25 °C (mean recovery 89 % at 60 °C, p < 0.01) or left under nitrogen post-drying (mean recovery at ambient + 15 min, 40 °C + 15mins and 60 °C + 15mins was 56 %, 12 % and 2 %, respectively, p < 0.01). Whilst dicarboxylic acids/medium chain fatty acids were unaffected by temperature (mean recovery 100 %), prolonged drying reduced recovery (mean recovery 85 % at 60 °C + 15mins, p < 0.01). ConclusionsEvaporation of solvent extracts with heat and/or prolonged drying under nitrogen results in significant losses of the shorter chain hydroxycarboxylic acids. The evaporation protocol must be carefully controlled to ensure accurate and reproducible results, preventing misdiagnoses and/or misinterpretation of results.

Identification of the mutations in BTD gene in Iranian patients with biotinidase deficiency and evaluating their genotype-phenotype correlations

BackgroundBiotinidase (BTD, encoded by the BTD gene) deficiency is an autosomal recessive neurometabolic disease caused by abnormal BTD activity in the biotin cycle. The clinical symptoms of patients, which are mainly neurocutaneous, range from mild to severe based on the enzyme activity level. This study aimed to identify BTD gene mutations in suspected BTD deficiency patients for the first time in the southwest of Iran and evaluate their genotype-phenotype correlations. Methods11 clinically and biochemically suspected patients from nine unrelated families and their available family members were subjected to Sanger sequencing. Segregation analysis was performed for novel mutation. The effect of each mutation on protein stability and hydropathicity, as well as the pathogenicity prediction of all detected mutations were assessed using various in silico analysis tools. ResultsSix mutations including a novel and five previously reported mutations were identified in patients with different ethnicities. Three out of five known mutations were reported for the first time in Iran. Various common clinical manifestations and a rarely reported coexistence of celiac disease in biotinidase deficiency patients were observed. The novel missense variant c.787G > A (p.Glu263Lys) was detected in exon 4 of the BTD gene, within the biotinidase-like domain of the BTD protein. This variation was found in two cousins of a family, both developed the same initial clinical presentation. In silico analysis revealed that this missense substitution decreased protein stability and increased protein hydrophilicity. Additionally, the known frameshift mutation c.1264delG (p.val422serfster59), was the most frequent allele in the studied population. We also predicted and visualized the effects of the novel and frameshift mutations on protein structure. ConclusionOur findings expanded the mutational spectrum of the BTD gene and provided valuable data on genotype-phenotype correlations, which helps in genetic counseling. Furthermore, the necessity of performing molecular analysis along with enzymatic analysis was highlighted by this study.

Alterations in optical coherence tomography and optical coherence tomography angiography findings in children with partial biotinidase deficiency.

The aim of the study was to investigate whether retinal neurovascular structural impairment in children with partial biotinidase deficiency (BD) could be detected early via optical coherence tomography (OCT) and OCT angiography (OCTA). Eighty patients with partial BD and 80 control cases without any known systemic or ocular diseases were enrolled in this prospective study. Retinal neurovascular structures in the macular and optic disc regions were examined in using OCT and OCTA. Data from subjects with partial BD were compared with data from healthy controls. A statistically significant decrease in the vessel density (VD) was observed in both superior and inferior parts of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) in the partial BD patient group compared with the control group (p<0.05). A significant decrease in the VD was also observed in the superior and inferior peripapillary SCP-DCP regions of the optic disc area in the patients with partial BD (p<0.05). Both the superficial and deep foveal avascular zone (FAZ) areas were significantly enlarged in the partial BD group with respect to the control group (p=0.026, p=0.021 respectively). In the partial BD patients, the vascular density in the macula and optic disc region is decreased in childhood, when compared to the control group. In patients with partial BD, it would be very useful to detect the early neurovascular changes that may occur during the course of the disease by means of a noninvasive technique such as OCTA.

Biallelic loss-of-function variations in BTD cause profound biotinidase deficiency in an Indian patient.

Biotinidase deficiency (BD) is a rare, autosomal recessive metabolic disorder characterized by neurocutaneous symptoms. This study investigates a case of profound BD in an Indian infant and the underlying genetic basis. A 10-month-old male presenting with seizures, hypotonia, ataxia, visual impairments, and developmental delay underwent biochemical and genetic analysis. Biotinidase activity was measured using an ELISA kit. Sanger sequencing of the biotinidase (BTD) gene was performed to identify genetic variations. In silico analysis was employed to assess the potential impact of the identified variants. The infant biotinidase activity was undetectable and its suggest profound biotinidase deficiency. Novel biallelic loss-of-function variations (c.903G > A and c.946C > T) in the BTD gene were identified, leading to premature stop codons and truncated, non-functional protein fragments. This case expands our knowledge of BD genetic diversity and underscores the critical role of early diagnosis and newborn screening programs in managing this treatable condition.

Oxford nanopore sequencing-based assay for BTD gene screening: Design, clinical validation, and variant frequency assessment in the Turkish population

Biotinidase deficiency (BTD) is an autosomal recessive disorder characterized by impaired recycling of the water-soluble vitamin biotin which leads to a spectrum of clinical manifestations ranging from mild to severe, including mainly neurological and cutaneous symptoms. Biotin supplementation is a cornerstone of treatment, but diagnosis often relies on measuring serum enzyme activity, which needs to be confirmed by genetic analysis. Thus, molecular methods become necessary in the differential diagnosis of BTD. Accordingly, countries with a high-incidence have implemented next-generation sequencing (NGS) techniques to newborn screening programs for BT. Nevertheless, NGS platforms, while well-established, present challenges in cost, labor, accessibility, and duration for newborn screening programs targeting BTD, therefore these limitations necessitate the exploration of alternative systems to ensure efficient and widespread screening. Here, third-generation sequencing platforms, notably Oxford Nanopore Technology (ONT), present promising solutions to the associated challenges. Hence, in the present study, we aimed to develop an ONT-based assay for the screening of BTD gene. After designing and optimizing primers for long-PCR using reference DNA, we assessed the performance of the ONT assay in BTD patients previously diagnosed by enzyme assay and confirmed using Illumina-based sequencing. The results demonstrate a strong correlation between the two methods, indicating the reliability of the ONT-based assay. Moreover, this first in-house single gene testing specifically tailored for BTD successfully detected previously known genetic variants with high sequencing depths, affirming the effectiveness of ONT-based sequencing in human genetics.

Biotin Homeostasis and Human Disorders: Recent Findings and Perspectives.

Biotin (vitamin B7, or vitamin H) is a water-soluble B-vitamin that functions as a cofactor for carboxylases, i.e., enzymes involved in the cellular metabolism of fatty acids and amino acids and in gluconeogenesis; moreover, as reported, biotin may be involved in gene regulation. Biotin is not synthesized by human cells, but it is found in food and is also produced by intestinal bacteria. Biotin status/homeostasis in human individuals depends on several factors, including efficiency/deficiency of the enzymes involved in biotin recycling within the human organism (biotinidase, holocarboxylase synthetase), and/or effectiveness of intestinal uptake, which is mainly accomplished through the sodium-dependent multivitamin transporter. In the last years, administration of biotin at high/"pharmacological" doses has been proposed to treat specific defects/deficiencies and human disorders, exhibiting mainly neurological and/or dermatological symptoms and including biotinidase deficiency, holocarboxylase synthetase deficiency, and biotin-thiamine-responsive basal ganglia disease. On the other hand, according to warnings of the Food and Drug Administration, USA, high biotin levels can affect clinical biotin-(strept)avidin assays and thus lead to false results during quantification of critical biomarkers. In this review article, recent findings/advancements that may offer new insight in the abovementioned research fields concerning biotin will be presented and briefly discussed.

Spontaneous recovery of partial biotinidase deficiency in two Saudi siblings

Spontaneous recovery of partial biotinidase deficiency in two Saudi siblings

Diagnosis and Treatment of Newborns Referred to the Metabolism Department From the National Newborn Screening Program in Türkiye: A 5-Year Single-Center Experience

Objective: The aims of this study were to investigate biochemical and genetic tests and treatment plans of newborns referred to our center with inherited metabolic disorders screened in Türkiye National Newborn Screening Program (NNSP). Material and Methods: The medical records of babies referred by the NNSP between January 2019 and November 2023 were scanned retrospectively. Plasma biotinidase activity and the biotinidase gene (BTD) analysis results for suspected biotinidase deficiency (BD), the plasma phenylalanine and phenylalanine hydroxylase gene (PAH) analysis for a suspicion of phenylketonuria (PKU) were documented with treatment information. Results: A total of 143 babies, 78 (54.5%) with suspected BD and 65 (45.5%) with suspected PKU were included. A PAH gene analysis was performed on 23 (35.4%) of those had high plasma phenylalanine levels, among which 86.9% were identified with the biallelic variant. Five patients were started on sapropterin-diet combined therapy, three on diet therapy and one on sapropterin therapy. In the first serum biotinidase activity measurement of babies referred with suspected BD, a heterozygous deficiency was detected in 48.7%, partial deficiency in 39.7% and profound deficiency in 10.3%. A BTD gene analysis was performed on 79.5% of those with suspected BD, and biallelic variants were detected in 50%. Forty-six patients (59.0%) underwent biotin treatment. Conclusion: In our study, approximately one-third of the babies referred from NNSP over the five-year course of the study had biallelic variants of the relevant disease. Our research is one of the few studies on NNSP in our country and presents the diagnosis and treatment process of PKU and BD.

Genotype-biochemical phenotype analysis in newborns with biotinidase deficiency in Southeastern Anatolia

ObjectiveBiotinidase deficiency (BTD) is characterized by a wide range of genetic variants. However, the correlation between these variants and the biochemical phenotypes of BTD is not well-established due to the diversity of the BTD gene, the variable nature of biotinidase, and difficulties in measuring enzyme activity. This study aims to identify BTD gene variants in newborns screened for biotinidase deficiency in Southeastern Anatolia and to examine the correlation between these variants and biochemical phenotypes.Materials and methodsBTD variant analysis and biotinidase enzyme (BT) activity measurements were performed on 711 newborns. Enzyme activity was measured using the colorimetric method. Biochemical phenotyping was categorized into three groups based on mean residual enzyme activity: profound (≤ 10%), partial (10.1–30%), and normal (> 30.1%). The pathogenicity of BTD gene variants was determined using BTD databases.ResultsThe biochemical phenotypes were distributed as follows: a) profound: n = 22 (3%), b) partial: n = 95 (13.3%), and c) normal: n = 594 (83.7%). The mean enzyme activities (%) for these groups were 8.79 ± 1.87, 22.67 ± 4.55, and 97.98 ± 17.45, respectively. The most common alleles and their frequencies were p.D444H (n = 526) (37%), p.R157H (n = 172) (12.1%), and p.C33Ffster*36 (n = 73) (9%). The pathogenicity of the variants was as follows: pathogenic: 481 (33.8%), likely pathogenic: 4 (0.2%), and variant of uncertain significance (VUS): 538 (37.8%).ConclusionIn this large cohort in Southeastern Anatolia, the most common alleles were p.D444H, p.R157H, and p.C33Ffster*36 in BTD variants. The results indicate a low concordance between the biochemical phenotype and genotype in newborns with BTD. This study highlights the inadequacy of predicting the biochemical phenotype based solely on variant pathogenicity in biotinidase deficiency during the neonatal period.

Feasibility of clinical newborn metabolic screening in a high-volume maternity center in Nepal

BackgroundStrategic action plans around newborn health evaluation are needed, to address the high neonatal mortality rate in Nepal. Surveillance systems, like Newborn Metabolic Screening (NBS), could reveal unrecognized drivers of neonatal death. NBS is not routinely performed in Nepal. Our objective was to determine the feasibility of establishing NBS, and its acceptability among healthcare providers and parents, in Nepal.MethodsThis prospective cohort study was conducted between November 2021 and May 2022 in term/late preterm infants born at Paropakar Maternity Hospital, Kathmandu, screening for 6 disorders that can be confirmed and managed locally. Staff were trained on dried-blood spot collection and transport protocols, performance metrics were established, and assays were performed at an accredited laboratory in Bangalore, India. Surveys were developed to determine acceptability among health-care providers and parents.ResultsOf 835 parents approached for the study, 825 (98.8%) consented. Parental surveys showed that 92% considered “no cost” option most important in choosing to participate in the study. Samples were transported to laboratories in Kathmandu and Bangalore in 36 ± 24 h, and 4.75 ± 1 days, which exceeded expected metrics of 24 and 48 h, respectively. Results were communicated to parents by 9.5 ± 2 days, which was within the expected metric window of 14 days. Abnormalities were reported in 13 infants and included 5 hemoglobinopathy traits (4 Hb E and 1 Hb D), 3 congenital hypothyroidism, 2 glucose-6-phosphate dehydrogenase deficiency, 1 congenital adrenal hyperplasia, 1 elevated acylcarnitine, and 1 biotinidase deficiency. Healthcare providers surveyed (n = 116) showed that 67% reported a moderate understanding of NBS; all indicated that screening would be beneficial. Most cited early diagnosis and treatment, as well as, providing risk to future pregnancies as significant benefits. 90% thought screening should be routinely performed.ConclusionsWe demonstrate that it is feasible to introduce NBS in Nepal. Transport metrics were longer than expected due to COVID pandemic travel restrictions; however, it was possible to deliver results to families within 2 weeks of birth. Parents overwhelmingly considered “no cost” option as the most important in choosing to screen. A government-sponsored program will be a key factor in establishing NBS in Nepal.

Outcome of Expanded Newborn Screening Among 194 000 Neonates at Northeast México.

Objectives. To describe the results of a 16-year experience of a state-coverage expanded newborn screening program (NBSP) in Northeast México. Methods. Between 2002 and 2017, dried blood spots of newborns were screened for congenital hypothyroidism (CH), congenital adrenal hyperplasia (CAH), biotinidase deficiency, galactosemia, cystic fibrosis, and glucose-6-phosphate dehydrogenase (G6PD) deficiency via immunofluorescence and amino and fatty acid disorders and organic acidemias using tandem mass spectrometry. Frequency rates were determined. Results. Overall, 192 487 samples were processed; 99.4% had negative results, and 598 were diagnosed. The frequency was 3.01/1000 newborns. G6PD deficiency, CH, amino acidemia, organic acidemia, cystic fibrosis, CAH, fatty acid oxidation disorder, galactosemia, and biotinidase deficiency cases were 1:773, 1:962, 1:4277, 1:4476, 1:11,322, 1:10,693, 1:10,693, 1:38,497, and 1:64,162, respectively. Conclusion. Using different technologies in NBSP increased the number of conditions detected, facilitating infant morbidity and mortality prevention. The frequency of disorders depends on the population's genetic background and diagnostic capacity.

Biotinidase biochemical and molecular analyses: Experience at a large reference laboratory.

Biotinidase deficiency is caused by absent activity of the biotinidase, encoded by the biotinidase gene (BTD). Affected individuals cannot recycle the biotin, leading to heterogeneous symptoms that are primarily neurological and cutaneous. Early treatment with biotin supplementation can prevent irreversible neurological damage and is recommended for patients with profound deficiency, defined as enzyme activity <10% mean normal (MN). Molecular testing has been utilized along with biochemical analysis for diagnosis and management. In this study, our objective was to correlate biochemical phenotype/enzyme activity to BTD genotype in patients for whom both enzyme and molecular testing were performed at our lab, and to review how the correlations inform on variant severity. We analyzed results of biotinidase enzyme analysis and BTD gene sequencing in 407 patients where samples were submitted to our laboratory from 2008 to 2020. We identified 84 BTD variants; the most common was c.1330G>C, and 19/84 were novel BTD variants. A total of 36 patients had enzyme activity <10% of MN and the most common variant found in this group was c.528G>T. No variant was reported in one patient in the profound deficiency group. The most common variant found in patients with enzyme activity more than 10% MN was c.1330G>C. Although enzyme activity alone may be adequate for diagnosing profound biotinidase deficiency, molecular testing is necessary for accurate carrier screening and in cases where the enzyme activity falls in the range where partial deficiency and carrier status cannot be discriminated.

Alopecia, Dermatitis and Seizures since Infancy: A Case of Biotinidase Deficiency

Abstract Background: Biotinidase deficiency is a rare autosomal recessive metabolic disorder, having a wide spectrum of neurological, cutaneous, and immune-dysfunction-related clinical manifestations, which may be overlooked as common pediatric ailments. Clinical Description: A 2-year–7-month-old girl child, second born to third-degree consanguineous parents, presented with fast breathing and altered sensorium for a day, with a history of seizures and skin lesions since early infancy, developmental delay, and ataxia. Management and Outcome: Investigations revealed a normal septic screen, with metabolic acidosis which was unresponsive to therapy. After stabilizing the child with respiratory and vasopressor support, investigations for immunodeficiency were sent. Tandem mass spectrometry revealed increased C5OH levels, suggestive of holocarboxylase deficiency. Specific enzyme assay showed biotinidase activity deficiency. The child was initially empirically treated with metabolic cocktail comprising carnitine, biotin, thiamine, C0-enzyme Q10, and riboflavin, followed by specific therapy with biotin. The child showed dramatic clinical improvement and normalization of blood gas. Treatment has been advised lifelong with biotin supplementation. Conclusion: Careful observation by a pediatrician can identify the typical combination of clinical features in a child, suggestive of biotinidase deficiency. Evaluation and management of the condition are simple and rewarding.

Case report of biotinidase deficiency in a 16-month-old child with emphasis on skin manifestations.

Case report of biotinidase deficiency in a 16-month-old child with emphasis on skin manifestations.

Profound Biotinidase Deficiency: A Rare but Treatable Inborn Error of Metabolism in a Neonate with Recurrent Seizures

Profound Biotinidase Deficiency: A Rare but Treatable Inborn Error of Metabolism in a Neonate with Recurrent Seizures

Biotinidase deficiency: a novel phenotype from a tertiary care centre

Biotinidase deficiency (BD) (OMIM 609019) autosomal recessive inherited metabolic disorder where enzyme biotinidase, is defective and biotin is not recycled in body. One novel phenotype reported from our tertiary care centre, 3-month-old baby presented with bilateral corneal haziness, development delay and seizures. Evaluation showed metabolic acidosis, persistent lactate elevation and MRI showed acute infract. Metabolic evaluation showed profound BD, confirmed by molecular testing. Treatment and follow up with biotin showed clearing of corneal opacity, resolution of bleed and improvement in development and seizures. BD has got wide range of clinical manifestations- neurologic, dermatologic, ophthalmologic and immunological features. Acute infract and corneal opacity are not yet reported in OMIM literature and BD not considered in differential diagnosis of stroke in metabolic disorders. Being clinicians, it is our responsibility to add novel associations and clinical findings and thus broaden the phenotype.