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Kannan B, Jayaseelan VP, Arumugam P, Navamani HK, Dv L. Biallelic loss-of-function variations in BTD cause profound biotinidase deficiency in an Indian patient. Mol Biol Rep 2024; 51:900. [PMID: 39120718 DOI: 10.1007/s11033-024-09827-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 07/29/2024] [Indexed: 08/10/2024]
Abstract
BACKGROUND 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. METHODS 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. RESULTS The infant biotinidase activity was undetectable and its suggest profound biotinidase deficiency. Novel biallelic loss-of-function variations (c.903G > A and c.946 C > T) in the BTD gene were identified, leading to premature stop codons and truncated, non-functional protein fragments. CONCLUSION 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.
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Affiliation(s)
- Balachander Kannan
- Molecular Biology Laboratory, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 600 077, TN, India
| | - Vijayashree Priyadharsini Jayaseelan
- Clinical Genetics Laboratory, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 600 077, TN, India
| | - Paramasivam Arumugam
- Molecular Biology Laboratory, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 600 077, TN, India.
| | - Hephzibah Kirubamani Navamani
- Department of Obstetrics and Gynecology, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha Medical College and Hospital, Saveetha University, Chennai, 602 105, TN, India
| | - Lal Dv
- Department of Pediatrics, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 602 105, TN, India
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Sharma R, Kucera CR, Nery CR, Lacbawan FL, Salazar D, Tanpaiboon P. Biotinidase biochemical and molecular analyses: Experience at a large reference laboratory. Pediatr Int 2024; 66:e15726. [PMID: 38299772 DOI: 10.1111/ped.15726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/11/2023] [Accepted: 10/31/2023] [Indexed: 02/02/2024]
Abstract
BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.
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Affiliation(s)
- Rajesh Sharma
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
| | - Cathlin R Kucera
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
| | - Camille R Nery
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
| | | | - Denise Salazar
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
| | - Pranoot Tanpaiboon
- Quest Diagnostics Nichols Institute, San Juan Capistrano, California, USA
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Kannan B, Navamani HK, Jayaseelan VP, Arumugam P. A Rare Biotinidase Deficiency in the Pediatrics Population: Genotype-Phenotype Analysis. J Pediatr Genet 2023; 12:1-15. [PMID: 36684547 PMCID: PMC9848769 DOI: 10.1055/s-0042-1757887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 09/06/2022] [Indexed: 11/07/2022]
Abstract
Biotinidase (BTD) deficiency is a rare autosomal recessive metabolic disorder caused by insufficient biotin metabolism, where it cannot recycle the vitamin biotin. When this deficiency is not treated with supplements, it can lead to severe neurological conditions. Approximately 1 in 60,000 newborns are affected by BTD deficiency. The BTD deficiency causes late-onset biotin-responsive multiple carboxylase deficiency, which leads to acidosis or lactic acidosis, hypoglycemia, and abnormal catabolism. BTD deficiency is of two types based on the amount of BTD Enzyme present in the serum. A wide range of pathogenic mutations in the BTD gene are reported worldwide. Mutations in the BTD gene lead to profound and partial BTD deficiency. Profound BTD deficiency results in a severe pathogenic condition. A high frequency of newborns are affected with the partial deficiency worldwide. They are mostly asymptomatic, but symptoms may appear during stressful conditions such as fasting or viral infections. Several pathogenic mutations are significantly associated with neurological, ophthalmological, and skin problems along with several other clinical features. This review discusses the BTD gene mutation in multiple populations detected with phenotypic features. The molecular-based biomarker screening is necessary for the disease during pregnancy, as it could be helpful for the early identification of BTD deficiency, providing a better treatment strategy. Moreover, implementing newborn screening for the BTD deficiency helps patients prevent several diseases.
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Affiliation(s)
- Balachander Kannan
- Molecular Biology Lab, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Hepzibah Kirubamani Navamani
- Department of Obstetrics and Gynaecology, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Saveetha Medical College and Hospitals, Chennai, Tamil Nadu, India
| | - Vijayashree Priyadharsini Jayaseelan
- Molecular Biology Lab, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Paramasivam Arumugam
- Molecular Biology Lab, Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
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Identification and Characterization of BTD Gene Mutations in Jordanian Children with Biotinidase Deficiency. J Pers Med 2020; 10:jpm10010004. [PMID: 31973013 PMCID: PMC7151559 DOI: 10.3390/jpm10010004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 12/04/2022] Open
Abstract
Biotinidase deficiency is an autosomal recessive metabolic disorder whose diagnosis currently depends on clinical symptoms and a biotinidase enzyme assay. This study aimed to investigate the mutational status and enzymatic activity of biotinidase deficiency in seven unrelated Jordanian families including 10 patients and 17 healthy family members. Amplified DNA was analyzed by the automated Sanger sequencing method, and the enzymatic assay was performed using a colorimetric assessment. Biotinidase level was significantly lower (p < 0.001) in BTD children compare to their non-affected family members. Genetic sequencing revealed six different mutations in Jordanian patients. One mutation was novel and located in exon 4, which could be a prevalent mutation for biotinidase deficiency in the Jordanian population. Identification of these common mutations and combing the enzymatic activity with genotypic data will help clinicians with regard to better genetic counseling and management through implementing prevention programs in the future.
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Peng G, de Fontnouvelle CA, Enns GM, Cowan TM, Zhao H, Scharfe C. Elevated methylmalonic acidemia (MMA) screening markers in Hispanic and preterm newborns. Mol Genet Metab 2019; 126:39-42. [PMID: 30448007 PMCID: PMC6361520 DOI: 10.1016/j.ymgme.2018.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 12/23/2022]
Abstract
Analysis of California newborn screening (NBS) data revealed a high prevalence of Hispanic infants testing positive for methylmalonic acidemia (MMA), a trend seen for both true- and false-positive cases. Here we show that Hispanic infants have significantly higher levels of MMA screening markers than non-Hispanics. Preterm birth and increased birth weight were found to be associated with elevated MMA marker levels but could not entirely explain these differences. While the preterm birth rate was higher in Blacks than Hispanics, Black infants had on average the lowest MMA marker levels. Preterm birth was associated with lower birth weight and increased MMA marker levels suggesting that gestational age is the stronger predictive covariate compared to birth weight. These findings could help explain why MMA false-positive results are more likely in Hispanic than in Black infants, which could inform screening and diagnostic procedures for MMA and potentially other disorders in newborns.
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Affiliation(s)
- Gang Peng
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Biostatistics, Yale University School of Public Health, New Haven, CT, United States
| | | | - Gregory M Enns
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States
| | - Tina M Cowan
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States
| | - Hongyu Zhao
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Biostatistics, Yale University School of Public Health, New Haven, CT, United States
| | - Curt Scharfe
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States.
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Wiltink RC, Kruijshaar ME, van Minkelen R, Onkenhout W, Verheijen FW, Kemper EA, van Spronsen FJ, van der Ploeg AT, Niezen-Koning KE, Saris JJ, Williams M. Neonatal screening for profound biotinidase deficiency in the Netherlands: consequences and considerations. Eur J Hum Genet 2016; 24:1424-9. [PMID: 27329734 PMCID: PMC5027693 DOI: 10.1038/ejhg.2016.65] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/09/2016] [Accepted: 05/20/2016] [Indexed: 11/08/2022] Open
Abstract
Biotinidase deficiency is a rare inherited metabolic disorder that can cause severe neurological symptoms. To prevent severe clinical presentations, it was included in the Dutch neonatal screening programme in 2007. Since then the number of cases detected has been high. This study set out to describe the incidence of the disease, the clinical and demographic characteristics of the neonates identified and the type of mutations found. In the south-western Netherlands, 304 982 neonates were screened between 2007 and 2012; and 92 were identified for further testing. Confirmatory testing revealed 6 (7%) with a profound biotinidase deficiency (<10% enzyme activity), 44 (48%) with a partial deficiency (10-30%) and 42 (46%) with normal activity (>30%). All six patients whose profound deficiency was confirmed had enzyme activities below 15% on neonatal screening. Mutation analysis was performed in 61 neonates: 5 'profound', 35 'partial' and 21 'normal'. All five 'profound' cases had two severe mutations. Comparison with the northern Netherlands showed that the frequency and types of mutation were representative for the Netherlands as a whole. The most common mutation detected was c.[1330G>C] (p.(Asp444His); 34%), which is considered to be mild, followed by three severe mutations c.[1368A>C], c.[1595C>T] and c.[1330G>C;511G>A]. Seven new mutations were identified. We conclude that neonatal screening for profound biotinidase produces a high number of false positives. Biotinidase deficiency was profound in less than 10% of cases identified. As biotinidase activity lay below 15% on neonatal screening in all such cases, the screening threshold might be reduced to 15%.
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Affiliation(s)
- Rachel C Wiltink
- Center for Lysosomal and Metabolic Diseases, Department of Paediatrics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Michelle E Kruijshaar
- Center for Lysosomal and Metabolic Diseases, Department of Paediatrics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Rick van Minkelen
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Willem Onkenhout
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Frans W Verheijen
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Evelien A Kemper
- Department of Clinical Chemistry, IJsselland ziekenhuis, Capelle aan den IJssel, The Netherlands
| | - Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ans T van der Ploeg
- Center for Lysosomal and Metabolic Diseases, Department of Paediatrics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Klary E Niezen-Koning
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Department of Laboratory Medicine, Center for Liver, Digestive and Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jasper J Saris
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Monique Williams
- Center for Lysosomal and Metabolic Diseases, Department of Paediatrics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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Abstract
OBJECTIVE To assess the incidence of biotinidase deficiency among newborns and their clinical outcome up to one year of age in a large pilot screening study in Minas Gerais, Brazil. METHODS A prospective cohort study was conducted from September 2007 to June 2008 with heel-prick blood samples collected on filter paper for the purpose of newborn screening. A qualitative colorimetric test was used as the primary screening method. Colorimetric-positive cases were further tested with a serum confirmatory assay. Gene sequencing was performed for eight children suspected with biotinidase deficiency and for some of their parents. Positive cases were daily supplemented with oral biotin and were followed up for approximately six years. RESULTS Out of 182,891 newborns screened, 129 were suspected of having biotinidase deficiency. Partial deficiency was confirmed in seven children (one was homozygous for p.D543E) and profound deficiency in one child (homozygous p.H485Q). Thus the incidence was one in 22,861 live births (95% confidence interval 1:13,503 to 1:74,454) for profound and partial biotinidase deficiency combined. Two novel mutations were detected: p.A281V and p.E177K. In silico analysis and estimation of the enzyme activity in the children and their parents showed that p.A281V is pathogenic and p.E177K behaves like p.D444H. CONCLUSION The incidence of biotinidase deficiency in newborn screening in Minas Gerais was higher than several international studies. The sample size should be larger for final conclusions. Oral daily biotin apparently precluded clinical symptoms, but it may have been unnecessary in some newborns.
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