Expert consensus on screening, diagnosis and treatment of multiple carboxylase deficiency.

Multiple carboxylase deficiency (MCD) includes autosomal recessive holocarboxylase synthetase (HLCS) deficiency and biotinidase (BTD) deficiency, which are caused by and gene mutations respectively. Neonatal screening for HLCS deficiency is based on 3-hydroxyisovaleryl carnitine in dry blood filter paper, and BTD deficiency is based on BTD activity determination. HLCS deficiency and BTD deficiency are characterized by neurocutaneous syndrome and organic aciduria, however, they are different in onset age, neurological symptoms and metabolic decompensation, which needed to be differentiated from acquired biotin deficiency or other genetic metabolic diseases. The diagnosis of the disease requires a combination of biochemical characteristics of hematuria, enzyme activity determination and genetic test. Routine biotin doses are effective for most MCD patients. This consensus is intended to benefit early screening and diagnosis of MCD.

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.

Cost-Effectiveness Methods and Newborn Screening Assessment.

Nowadays, health funding decisions must be supported by sound arguments in terms of both effectiveness and economic criteria. After more than half a century of newborn screening for rare diseases, the appropriate economic evaluation framework for these interventions is still challenging. The validity of standard methods for economic evaluation heavily relies on the availability of robust evidence, but collection of such evidence is precluded by the rareness of the conditions that may benefit from screening. Furthermore, there are a series of conceptual and methodological limitations that warrant further careful consideration when assessing the cost-effectiveness of newborn screening programs. In this chapter we provide a general overview of current economic evaluation methods and the challenges for their application to newborn screening programs.

Novel imaging findings in two cases of biotinidase deficiency-a treatable metabolic disorder.

Biotinidase deficiency is one of the few treatable inborn errors of metabolism. We describe unique MRI features in two patients with biotinidase deficiency. Brain MRI in case one demonstrated symmetrical diffusion restriction in bilateral hippocampi, parahippocampal gyri, central tegmental tracts, and cerebellar white matter besides other structures that have been reported previously. The second patient was noted to have bilateral symmetrical T2 hyperintensities involving the anterior, lateral and posterior columns of the entire spinal cord on MRI. Knowledge of the varied MRI features of biotinidase deficiency will aid the prompt diagnosis and treatment of a potentially disabling illness, especially in countries where newborn screening is not routinely performed.

La importancia de una ley a tiempo: Presentación de un caso de deficiencia de biotinidasa no diagnosticado por pesquisa neonatal / The importance of a law on time: presentation of a girl with biotinidase deficiency who was not picked up through the neonatal screening

En agosto de 2008, la Provincia de Buenos Aires no había adherido a la Ley Nacional 26279, que establece la obligatoriedad de la pesquisa neonatal para la deficiencia de biotinidasa, entre otras enfermedades. En esa fecha, nace en la Provinciade Buenos Aires una niña que derivan desde una terapia intensiva pediátrica al Hospital Nacional de Pediatría Dr. Prof. J. P. Garrahan, a los 58 días de vida, por alteración del sensorio, acidosis metabólica, hiperlacticoacidemia, alopecia, conjuntivitis y erupción cutánea eritematosa escaldada. Por estaclínica (de 13 días de evolución) se mide la actividad plasmática de biotinidasa, que resultó baja. Se inicia tratamiento con biotina y revierten rápidamente las alteraciones bioquímicas que presentaba. Si se hubiera hecho la pesquisa neonatal, estaniña no hubiera estado expuesta a riesgo de muerte por la enfermedad y se hubiese asegurado (por el inicio presintomático del tratamiento), un desarrollo normal, ya que las lesiones neurológicas no siempre retrogradan o no lo hacen ad integrum.

Hearing loss in biotinidase deficiency: genotype-phenotype correlation.

Children with symptoms of profound biotinidase deficiency with null mutations are more likely to have hearing loss develop than those with missense mutations, even if not treated for a period of time. Hearing loss appears to be preventable in children with null mutations if treatment is initiated soon after birth.

Successful pregnancy in a treated patient with biotinidase deficiency.

We report a patient with biotinidase deficiency treated with biotin during pregnancy with favourable outcome.

Biotinidase deficiency: a treatable genetic disorder in the Saudi population.

Biotinidase deficiency is an autosomal recessive genetic disorder which is not uncommon in the Saudi population. Biotinidase is responsible for biotin recycling and biotin is an essential cofactor for activation of the carboxylase enzymes. Absence of biotinidase leads to infantile or early childhood encephalopathy, seizure disorder, dermatitis, alopecia, neural deafness and optic atrophy. The disease can be diagnosed by simple fluorometric enzyme assay. Treatment with biotin is both cheap and simple, resulting in rewarding clinical recovery and normalization of the biochemical, neuroradiological and neurophysiological parameters. If neglected, however, a patient may die of acute metabolic acidosis or may suffer from permanent neural deafness and optic atrophy, with mental and motor handicap. We describe the detection and treatment of 20 cases of biotinidase deficiency in our hospital and recommend the introduction of a neonatal screening programme for this disorder.