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Irreversibility of Symptoms with Biotin Therapy in an Adult with Profound Biotinidase Deficiency.

ABSTRACT: We report a 36-year-old woman who exhibited progressive optic atrophy at 13 years old, then stroke-like episodes and spastic diplegia in her 20s. Biotinidase deficiency was not readily considered in the differential diagnosis, and the definitive diagnosis was not made until pathological variants of the biotinidase gene (BTD) were found by exome sequencing. Profound biotinidase deficiency was confirmed by enzyme analysis. Unfortunately, her symptoms did not resolve or improve with biotin treatment. Biotin therapy is essential for all individuals with profound biotinidase deficiency and for preventing further damage in those who already exhibit irreversible neurological damage. Newborn screening for the disorder would have avoided years of clinical symptoms that now appear to be irreversible with biotin treatment.

SUBMITTER: Ferreira P

PROVIDER: S-EPMC5680287 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Irreversibility of Symptoms with Biotin Therapy in an Adult with Profound Biotinidase Deficiency.

Ferreira Patrick P Chan Alicia A Wolf Barry B

JIMD reports 20170221

We report a 36-year-old woman who exhibited progressive optic atrophy at 13 years old, then stroke-like episodes and spastic diplegia in her 20s. Biotinidase deficiency was not readily considered in the differential diagnosis, and the definitive diagnosis was not made until pathological variants of the biotinidase gene (BTD) were found by exome sequencing. Profound biotinidase deficiency was confirmed by enzyme analysis. Unfortunately, her symptoms did not resolve or improve with biotin treatmen ...[more]

PMID: 28220409

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Project description:Biotinidase (BTD) deficiency (OMIM 253260) is an autosomal recessively inherited metabolic disorder resulting from deficient activity of the BTD enzyme, which can cleave and release biotin from a variety of biotin-dependent carboxylases, and is therefore recognized as a tool to recycle biotin. Being a condition caused by variations on BTD gene with a consequence of free biotin shortage, BTD deficiency may impair the activity of biotin-dependent carboxylases, and thus bring about a buildup of potentially toxic compounds in the body, primarily 3-hydroxyisovaleryl-carnitine in plasma as well as 3-hydroxyisovaleric acid in urine. The phenotype of BTD deficiency may vary dramatically, from asymptomatic adults to severe neurological anomalies, even death in infancy. In the present study, we reported on a 5-month-old boy, whose parents sought for medical consultation in our clinic for their son due to his loss of consciousness, repeated tetany, and motor retardation. Detailed clinical features included severe psychomotor retardation, hypotonia, as well as failure to thrive. The brain MRI at 12 months showed cerebellar hypoplasia and multiple foci of leukodystrophy. The result of antiepileptic therapy was not satisfying. During hospitalization, BTD deficiency was suggested by elevated concentration of 3-hydroxyisovaleryl-carnitine in the blood spots and 3-hydroxyisovaleric acid in the urine. The child was then diagnosed with profound BTD deficiency based on the above findings and low BTD enzyme activity. Subsequent mutational analysis revealed a novel homozygous variant, c.637_637delC (p.H213Tfs*51) in exon 4 of BTD gene in the proband, which was recognized as a further support to the diagnosis. Therefore, biotin treatment was started immediately, eventually with satisfactory outcomes achieved in terms of prevention of epileptic seizure, performance in deep tendon reflexes, and improvement of muscular hypotonia, but unfortunately, the therapy failed to show any evident effects on poor feeding and intellectual disability. This painful lesson suggests that newborn screening for inherited metabolic diseases is essential for early identification and treatment, which should have been performed in this case to avoid this tragedy.

Project description:IntroductionBiotinidase deficiency (BTD) is an inborn error of biotin metabolism inherited as an autosomal recessive trait. Due to the, biotinidase deficiency, biotin is not recycled. Individuals with BTD usually exhibit neurological and cutaneous abnormalities unless treated with biotin. Supplementation with biotin may either ameliorate or if early introduced even prevent symptoms when introduced presymptomatically.Patients and methodsSince 1991, 22 Polish patients from 19 families have been diagnosed with BTD. In 16 children the diagnosis had been suspected on the basis of clinical signs: skin lesions, hyperventilation, seizures, spasticity, and laboratory investigation (elevated lactate and metabolites on urine organic acids profile). The defect was enzymatically (serum biotinidase activity measurement) and genetically (tested for mutations in the BTD gene) confirmed afterwards. All patients were treated with biotin. Urine organic acids analysis (GC/MS) for 3-hydroxizovaleric acid was used for patients' monitoring. Neurological, audiological and ophthalmological evaluation has been conducted once a year.ResultsIn 5 symptomatic patients a progressive optic nerve atrophy had already been noted at the time of treatment initiation. In these patients sensorineural hearing loss has also been diagnosed despite biotin supplementation. Asymptomatic patients treated with biotin supplementation presented no signs or symptoms of BTD. Supplementation with biotin slows the progression of BTD in symptomatic patients, but does not reverse nerve atrophy. Nonetheless, introduction of the treatment with biotin during presymptomatic stage of the disease prevents the onset of symptoms including optic atrophy and hearing loss. Homozygosity for the p.Leu215Phe mutation in BTD gene seems to be frequent in patients from the North-Eastern region of Poland and is connected with the hearing loss.ConclusionSince the prognosis for individuals diagnosed with BTD is good, provided they are treated before symptoms occur, it is justified to add this metabolic disorder to the panel of conditions screened under the national newborn screening programme in Poland.

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Irreversibility of Symptoms with Biotin Therapy in an Adult with Profound Biotinidase Deficiency.

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Irreversibility of Symptoms with Biotin Therapy in an Adult with Profound Biotinidase Deficiency.

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