Audiologic findings in children with biotinidase deficiency in Turkey

Cochlear Implantation in Biotinidase Enzyme Deficiency

Metabolic syndromes associated with hearing loss are rare and are characterized by specific enzyme pathway deficiencies involving lysosomal storage, peroxisomes, fatty acid enzymes, organic acids and amino acids. The deficiency of biotinidase, an enzyme involved in the metabolism of biotin, is one such rare cause of congenital hearing loss estimated at 1:60,000 newborns. The parents of a 5-year-old girl presented to the clinic with complaints that she was hard of hearing with no speech development. At age 2 she had been diagnosed with organic aciduria and hydronephrourethrosis and was operated for renal calculi. Clinical examination showed periorificial scaly skin lesions and eczematous otitis externa. An audiological evaluation showed bilateral profound SNHL. Imaging and routine investigations were unremarkable, except for a mild low anion gap metabolic acidosis. General anaesthesia involved avoidance of neuromuscular agents due to the risk of inducing hypotonia. Surgery consisted of cortical mastoidectomy followed by the facial recess approach. A standard electrode array was inserted via the round window technique and complete atraumatic insertion was achieved. Intraoperative electrode impedance and NRT tracings were good. Hearing loss in biotinidase deficiency may be expected to be of progressive nature and regular evaluation of hearing and speech is required. Cochlear implantation is currently the best available solution for severe to profound hearing loss in this disorder although the enzymatic pathology affects the entire auditory pathway. Biotin supplementation is required lifelong for its management.

Alterações auditivas e deficiência de biotinidase: revisão integrativa da literatura

ABSTRACT Purpose: to review the available literature on the relationship between hearing disorders and Biotinidase deficiency. Methods: a literature search carried out between October 2018 and August 2021, on the following databases: ELSEVIER, MEDLINE, SciELO, LILACS. Descriptors were used in English, Portuguese, and Spanish. PRISMA tools were used to select the articles and STROBE was used to analyze them. Literature Review: the selected articles were published between 1983 and 2020 and answered the guiding question of the research. Observational studies, case series studies, and case reports were included. Articles without a methodology description, or carried out by the same author and with the same sample were excluded. The initial search strategy identified 152 articles. After applying the inclusion and exclusion criteria, 14 articles were selected for this review. Conclusion: the presence of Biotin was often associated with auditory pathways origins. The literature suggested a relationship between Biotinidase deficiency and hearing disorders.

Hearing disorders and biotinidase deficiency: an integrative literature review

ABSTRACT Purpose: to review the available literature on the relationship between hearing disorders and Biotinidase deficiency. Methods: a literature search carried out between October 2018 and August 2021, on the following databases: ELSEVIER, MEDLINE, SciELO, LILACS. Descriptors were used in English, Portuguese, and Spanish. PRISMA tools were used to select the articles and STROBE was used to analyze them. Literature Review: the selected articles were published between 1983 and 2020 and answered the guiding question of the research. Observational studies, case series studies, and case reports were included. Articles without a methodology description, or carried out by the same author and with the same sample were excluded. The initial search strategy identified 152 articles. After applying the inclusion and exclusion criteria, 14 articles were selected for this review. Conclusion: the presence of Biotin was often associated with auditory pathways origins. The literature suggested a relationship between Biotinidase deficiency and hearing disorders.

Clinical, biochemical and genotypical characteristics in biotinidase deficiency

OBJECTIVES

Hypotonia, lethargy, eczema, alopecia, conjunctivitis, ataxia, hearing loss, optic atrophy, cognitive retardation, and seizures can occur in patients with biotinidase deficiency, and it is inherited as autosomal recessive. The aim of this study was to evaluate the cases followed up with the diagnosis of biotinidase deficiency in our unit, in terms of clinical, biochemical and genetic analyses.

METHODS

A total of 112 cases followed up in our centre with the diagnosis of biotinidase deficiency between August 2018-September 2020 were included in the study. Data were collected retrospectively.

RESULTS

A total of 112 cases (55.4% male, mean age: 2.2 ± 2.8 years) diagnosed with biotinidase deficiency were evaluated. Diagnoses were made by newborn screening in 90.2% of the cases, by family screening in 4.5%, and by investigating symptoms in 5.4%. The most frequently (27.5%) detected mutations were c.1330G>C (p.D444H)/c.1330G>C (p.D444H) homozygous mutation, followed by (13.0%) c.1330G>C (p.D444H)/c.470G>A (p.R157H) compound heterozygous mutation, and (13.0%) c.470G>A (p.R157H)/c.470G>A (p.R157H) homozygous mutation. Biotinidase enzyme levels were found to be higher in patients with the p.D444H homozygous mutation than patients with other mutations. Biotin treatment was started in all patients with enzyme deficiency.

CONCLUSIONS

Since the treatment is inexpensive and easily available, it is vital to detect this disease before symptom onset, especially findings related to the central nervous system, hearing and vision loss. In patients diagnosed with enzyme deficiency, the diagnosis should be definitively confirmed by genetic analysis.

Two novel BTD mutations causing profound biotinidase deficiency in a Chinese patient

Background

Biotinidase deficiency (OMIM 253260) is an autosomal recessively inherited disorder affecting about 1/60,000 people worldwide. The absence or deficiency of biotinidase impairs free biotin recycling and affects biotin‐dependent carboxylase functions.

Methods

A Chinese patient with spontaneous recurrent epilepsy, an eczema‐like rash, hair loss, hypotonia, and hearing loss began at three months of age. Her biotinidase activity was 1.0 nmol/ml/min, 9.5% of the mean control activity, which confirmed profound biotinidase deficiency.

Results

Compound heterozygous for c.250‐1G > C and c.878dupT variants in the BTD gene were identified in this patient. These two variants were novel and absent in the population matched controls and any databases.

Conclusions

This study expanded the mutation spectrum of alterations of the BTD gene. Our patient also emphasized the critical role of biotinidase activity measurement combined with mutation analysis in early diagnosis of biotinidase deficiency.

Effect of perinatal biotin deficiency on auditory pathway of the Wistar-Albino rats

Aim: Severe biotin deficiency associated with biotinidase enzyme deficiency in newborns is seen as severe neurological problems and hearing loss. However, the effect on the infant of deficiencies in the maternal diet during pregnancy are not clear. Material and methods: The study included 16 female Wistar albino rats and 4 male Wistar albino rats, that were mated and then the females were separated into 4 groups. At 40 days after the birth, 3 pups were selected from each group, and these 12 pups were evaluated with DPOAE and ABR electrophysiologically and the cochlea was examined ultrastructurally with electron microscopy. Results: In the DPOAE evaluation, At 8000 and 11,000 Hz, the signal-noise ratios in the B-N and B-B groups were statistically significantly higher (p < .05). In ABR, lengthening of the latency periods was determined in all the waves at both 8 and 16 kHz in the B-B group. When the IPL periods were examined, lengthening in IPL 1-5 was statistically significant in the B-B group only at 8 kHz. Conclusions: Biotin can be said to have an effect on hearing pathways. However, specifically where on the hearing pathways that biotin is involved has not been clarified.

Single center experience of biotinidase deficiency: 259 patients and six novel mutations

Background Biotinidase deficiency (BD) is an autosomal recessively inherited disorder of biotin recycling. It is classified into two levels based on the biotinidase enzyme activity: partial deficiency (10%-30% enzyme activity) and profound deficiency (0%-10% enzyme activity). The aims of this study were to evaluate our patients with BD, identify the spectrum of biotinidase (BTD) gene mutations in Turkish patients and to determine the clinical and laboratory findings of our patients and their follow-up period. Methods A total of 259 patients who were diagnosed with BD were enrolled in the study. One hundred and forty-eight patients were male (57.1%), and 111 patients were female (42.9%). Results The number of patients detected by newborn screening was 221 (85.3%). By family screening, 31 (12%) patients were diagnosed with BD. Seven patients (2.7%) had different initial complaints and were diagnosed with BD. Partial BD was detected in 186 (71.8%) patients, and the profound deficiency was detected in 73 (28.2%) patients. Most of our patients were asymptomatic. The most commonly found variants were p.D444H, p.R157H, c.98_104delinsTCC. The novel mutations which were detected in this study are p.D401N(c.1201G>A), p.A82G (c.245C>G), p.F128S(c.383T>C), c617_619del/TTG (p.Val207del), p.A287T(c.859G>A), p.S491H(c.1471A>G). The most common mutation was p.R157H in profound BD and p.D444H in partial BD. All diagnosed patients were treated with biotin. Conclusions The diagnosis of BD should be based on plasma biotinidase activity and molecular analysis. We determined the clinical and genetic spectra of a large group of patients with BD from Western Turkey. The frequent mutations in our study were similar to the literature. In this study, six novel mutations were described.

Cutaneous manifestations of nutritional deficiency

PURPOSE OF REVIEW

Childhood malnutrition is a major global health issue. It is often thought of as a developing world problem and therefore, underdiagnosed or misdiagnosed in developed countries. The delay in diagnosis and treatment can lead to increased morbidity and mortality. Cutaneous manifestations are often the initial presenting signs of nutritional deficiency. Early recognition is essential in timely initiation of the necessary interventions. This article will review pertinent cutaneous findings and systemic manifestations associated with common nutritional deficiencies.

RECENT FINDINGS

Malnutrition has historically been associated with poverty in developing countries. However, recent literatures suggest that the incidence of nutritional deficiencies continuous to rise among infants from developed countries, as a result of dietary restrictions because of perceived food allergies or intolerance. It is also an emerging finding in children with complicated medical problems.

SUMMARY

It is very important to raise awareness about cutaneous manifestations of nutritional deficiency as early and appropriate treatment results in excellent prognosis.

Clinical, Biochemical and Outcome Profile of Biotinidase Deficient Patients from Tertiary Centre in Northern India

INTRODUCTION

Biotinidase deficiency is an inherited metabolic disorder with estimated birth incidence of 1 in 61,000 for profound and partial deficiency. Estimated incidence of profound and partial biotinidase deficiency is 1 in 1, 37,000 and 1 in 1, 10,000 respectively. The carrier frequency in general population is 1 in 120. We attempt to study clinical, biochemical and outcome from 10 Biotinidase deficient patients.

MATERIALS AND METHODS

A retrospective case record study was conducted to record Clinical, biochemical and outcome profile from genetic records. Biotinidase level was measured using spectrophotometric method.

RESULTS

Study group comprised of 8 males and 2 females with median age of presentation 6 (2-45.75) months. Median (interquartile range) Biotinidase level in study group 0.3 (0.08-1.5) nmol/ml/min. Study group was further divided in to early onset group (< 12 months, n-6) and late onset group (> 12 months, n-4). Seizure, alopecia and hearing loss were predominant phenotypes in study group. The other rare presentations were: hypotonia, ataxia, skin rash, seborrhoea. The most common seizure type was focal seizure. Control of seizure activity was important immediate outcome measured in study group. Median duration (interquartile range) of seizure control in early onset group was 3 (2-4)days against 13.5 (12.25-14.75) days in late onset group.

CONCLUSION

This study highlights the need of early diagnosis for favourable outcome for a potentially treatable inherited metabolic disorder.

Cost-Effectiveness Analysis of a National Newborn Screening Program for Biotinidase Deficiency

BACKGROUND AND OBJECTIVES

There are conflicting views as to whether testing for biotinidase deficiency (BD) ought to be incorporated into universal newborn screening (NBS) programs. The aim of this study was to evaluate the cost-effectiveness of adding BD to the panel of conditions currently screened under the national NBS program in Spain.

METHODS

We used information from the regional NBS program for BD that has been in place in the Spanish region of Galicia since 1987. These data, along with other sources, were used to develop a cost-effectiveness decision model that compared lifetime costs and health outcomes of a national birth cohort of newborns with and without an early detection program. The analysis took the perspective of the Spanish National Health Service. Effectiveness was measured in terms of quality-adjusted life years (QALYs). We undertook extensive sensitivity analyses around the main model assumptions, including a probabilistic sensitivity analysis.

RESULTS

In the base case analysis, NBS for BD led to higher QALYs and higher health care costs, with an estimated incremental cost per QALY gained of $24,677. Lower costs per QALY gained were found when conservative assumptions were relaxed, yielding cost savings in some scenarios. The probability that BD screening was cost-effective was estimated to be >70% in the base case at a standard threshold value.

CONCLUSIONS

This study indicates that NBS for BD is likely to be a cost-effective use of resources.