A girl with spastic tetraparesis associated with biotinidase deficiency

Neuroimaging Features of Biotinidase Deficiency

Biotinidase deficiency is an autosomal recessive condition caused by pathogenic variants in the BTD gene. Resultant deficiency of free biotin leads to impaired activity of the enzyme carboxylase and related neurologic, dermatologic, and ocular symptoms. Many of these are reversible on treatment, but early recognition and commencement of biotin supplementation are critical. This practice is especially important in countries where routine neonatal screening for biotinidase deficiency is not performed. In this report comprising 14 patients from multiple centers, we demonstrate the MR imaging patterns of this disorder at various age groups. Knowledge of these patterns in the appropriate clinical context will help guide early diagnosis of this treatable metabolic disorder.

Severe Distal Motor Involvement in a Non-compliant Adult With Biotinidase Deficiency: The Necessity of Life-Long Biotin Therapy

Biotinidase deficiency is an autosomal recessive disorder in which affected individuals are unable to recycle biotin. Untreated, children usually exhibit hypotonia, seizures, ataxia, developmental delay, and/or hearing loss. Individuals diagnosed by newborn screening have an excellent prognosis with life-long biotin supplementation. We report a young adult diagnosed with profound biotinidase deficiency by newborn screening who was asymptomatic while on therapy. At 18 years of age, 6 months after voluntarily discontinuation of biotin, he developed a progressive distal muscle weakness. Molecular analysis of the BTD gene showed a pathogenic homozygous duplication c.1372_1373dupT p.(Cys458LeufsTer26) (1). Despite 16 months since reintroduction of biotin, muscle strength only partially recovered. Transition to adulthood in chronic metabolic diseases is known to be associated with an increased risk for non-compliance. Neurological findings in this adult are similar to those described in others with adult-onset biotinidase deficiency. Long-term prognosis in non-compliant symptomatic adult with biotinidase deficiency likely depends on the delay and/or severity of intervening symptoms until reintroduction of biotin.

Genetic mimics of cerebral palsy

The term "cerebral palsy mimic" is used to describe a number of neurogenetic disorders that may present with motor symptoms in early childhood, resulting in a misdiagnosis of cerebral palsy. Cerebral palsy describes a heterogeneous group of neurodevelopmental disorders characterized by onset in infancy or early childhood of motor symptoms (including hypotonia, spasticity, dystonia, and chorea), often accompanied by developmental delay. The primary etiology of a cerebral palsy syndrome should always be identified if possible. This is particularly important in the case of genetic or metabolic disorders that have specific disease-modifying treatment. In this article, we discuss clinical features that should alert the clinician to the possibility of a cerebral palsy mimic, provide a practical framework for selecting and interpreting neuroimaging, biochemical, and genetic investigations, and highlight selected conditions that may present with predominant spasticity, dystonia/chorea, and ataxia. Making a precise diagnosis of a genetic disorder has important implications for treatment, and for advising the family regarding prognosis and genetic counseling. © 2019 International Parkinson and Movement Disorder Society.

Biotinidase deficiency should be considered in individuals thought to have multiple sclerosis and related disorders

BACKGROUND

Multiple sclerosis is a disorder of the central and peripheral nervous system of young and old adults that is characterized by muscle, coordination and vision abnormalities. Multiple sclerosis is likely due to numerous causes.

METHODS

Recently, adolescents and adults with ophthalmological and or neurological findings have been diagnosed with biotinidase deficiency. These individuals have exhibited myelopathy, paresis and/or spastic diplegia/tetraplegia with or without optic neuropathy/vision loss. These older individuals with biotinidase deficiency were considered initially to have multiple sclerosis or similar disorders before they were determined to have biotinidase deficiency.

RESULTS

If a symptomatic individual with biotinidase deficiency is treated with biotin early enough, the symptoms markedly improve or completely resolve, but if treatment is delayed, the symptoms may be irreversible.

CONCLUSION

Therefore, although biotinidase deficiency is rare relative to that of multiple sclerosis, the disorder should be included in the differential diagnosis of individuals thought to have multiple sclerosis or related disorders. Biotinidase deficiency should be considered in individuals thought to have multiple sclerosis or related disorders.

A Review of the Use of Biotin for Hair Loss

BACKGROUND

Biotin has gained commercial popularity for its claimed benefits on healthy hair and nail growth. Despite its reputation, there is limited research to support the utility of biotin in healthy individuals.

OBJECTIVE

To systematically review the literature on biotin efficacy in hair and nail growth.

METHODS

We conducted a PubMed search of all case reports and randomized clinical trials (RCTs) using the following terms: (biotin and hair); (biotin and supplementation and hair); (biotin supplementation); (biotin and alopecia); (biotin and nails); (biotin and dermatology), and (biotin recommendations).

RESULTS

We found 18 reported cases of biotin use for hair and nail changes. In all cases, patients receiving biotin supplementation had an underlying pathology for poor hair or nail growth. All cases showed evidence of clinical improvement after receiving biotin.

CONCLUSIONS

Though its use as a hair and nail growth supplement is prevalent, research demonstrating the efficacy of biotin is limited. In cases of acquired and inherited causes of biotin deficiency as well as pathologies, such as brittle nail syndrome or uncombable hair, biotin supplementation may be of benefit. However, we propose these cases are uncommon and that there is lack of sufficient evidence for supplementation in healthy individuals.

Biotinidase deficiency mimicking neuromyelitis optica beginning at the age of 4: A treatable disease

BACKGROUND

Metabolic and inflammatory conditions may lead to neurological disorders. Neuromyelitis optica spectrum disorders (NMOSDs) refer to a rare group of demyelinating diseases of the central nervous system which essentially involve the optic nerves and spinal cord.

METHODS

We report a case of biotinidase deficiency (BD) initially misdiagnosed as NMOSD in a pediatric patient.

RESULTS

An 8-year-old girl was initially diagnosed with NMOSD on the basis of optic neuritis (ON) associated with three episodes of longitudinally extensive transverse myelitis (LETM). Intravenous high-dose corticosteroids were effective during the first two episodes of LETM. The third acute episode which resulted in tetraplegia, respiratory distress, and blindness was refractory to corticosteroids, plasmapheresis, and rituximab. The unusual clinical course and persistent high levels of plasma and cerebrospinal fluid (CSF) lactate led to additional metabolic investigations being performed. Acylcarnitine profile revealed increased C5-OH acylcarnitine suggestive of BD. Diagnosis was confirmed by direct assessment of plasma enzyme activity (quantified as 5% of the control value). Genetic analysis revealed two mutations, c.643C>T (p.L215F) and c.1612C>T (p.R538C), in the BTD gene (3p25). Dramatic clinical improvement occurred after long-term oral biotin treatment.

CONCLUSION

BD is a treatable condition that may closely mimic the neurological findings of LETM and NMOSD.

Biotinidase deficiency should be considered in individuals exhibiting myelopathy with or without and vision loss

Multiple symptomatic children with biotinidase deficiency have exhibited spastic para- or tetraplegia due to myelopathy with and without vision loss. Although this has been a feature of what has been designated as delayed onset-biotinidase deficiency, myelopathy is likely also on the continuum of clinical features seen in younger children who have had these features attributed to dysfunction of the upper brain rather than of the spinal cord. Because many countries are still not screening their newborns for biotinidase deficiency, the disorder should be included in the differential diagnosis of individuals with myelopathic symptoms. Many of these children have gone weeks to months before they were correctly diagnosed with biotinidase deficiency. Rapid recognition that a child with myelopathy with and without vision loss has biotinidase deficiency will undoubtedly facilitate prompt treatment, increase the possibility of complete recovery and avoid potential residual permanent neurological damage. Newborn screening for biotinidase deficiency would avoid the delay in the diagnosis and treatment of individuals who otherwise may present with myelopathic or other neurological symptoms.