ABSTRACT
Objective:To describe the clinical features of pediatric biotinase deficiency (BTD) manifested as spinal cord disease.Methods:The clinical data of a child with spinal cord lesions due to biotinase deficiency, diagnosed in Beijing Children′s Hospital in 2020, were collected. The cases with complete clinical data retrieved on literature reported in China National Knowledge Infrastructure, Wanfang Data knowledge Service Platform and PubMed (up to August 2021) by using search terms of biotinase deficiency, pediatric, spinal cord, myelopathy and myelitis were summarized.Results:The patient was a 3 years and 5 months old boy with the main clinical manifestations of subacute progressive limb weakness and wheezing. Physical examination showed sparse hair, rough skin, spastic paraparesis and developmental delay. Cerebrospinal lactic acid was increased (5.67 mmol/L). Cranial magnetic resonance imaging (MRI) showed diffuse T 2/fluid attenuated inversion recovery hyperintensity of the midbrain, dorsal pons, edulla, periacqueductal grey and optic tracts. Spinal cord lesions were extended from the medulla up to the level of the conus. Urineketone bodies and 3-hydroxyisurate were increased. The activity of biotinidase was 0.27 pmol/min (3 mm disc), being 7% of mean normal serum activity. Genetic studies revealed homozygous mutation in the BTD gene [c.284T>A (p.I95N)]. After biotin supplementation for 6 months, the only evident abnormality was residual spasticity of lower limbs. Fourteen English literatures and 2 Chinese literatures including 18 cases were collected. The onset age was from 2 months to 15 years (median age was 4 years). Among them, 11 cases had cranial MRI abnormalities, of which all involved brain stem, 6 cases involved optic tracts and (or) optic chiasm. All 18 cases had spinal cord MRI abnormalities with longitudinally extensive lesion, mostly involved cervical and thoracic spinal segments, and 3 cases involved all spinal segments. Twelve cases received immunotherapy, and 6 were partially improved, 6 were completely invalid. After biotin supplementation, 12 patients had neurological disability. Conclusions:BTD should be included in the differential diagnosis of subacute myelopathy, regardless of the onset age. Early diagnosis and treatment can prevent irreversible neurological damage.
ABSTRACT
Objective To explore the diagnosis and treatment of biotinase deficiency (BTD) manifested as encephalomyelopathy.Methods The clinical data of one child with BTD were retrospectively analyzed.The pertinent literatures were reviewed.Results A six-year-old male child suffered from progressive spastic paralysis of lower limbs for 3 months before admission.A similar symptoms occurred after a cold in 3-year-old.It was easy to peel skin on her hands and she had angular stomatitis.Audio visual evoked potential was detected to be abnormal in other hospital.After hospitalizion,the cerebrospinal fluid examination was normal,and MRI showed long T1 long T2 signals bilateral occipital lobe and basal ganglia region.Because the child represented medulla palsy,and so the tracheal intubation ventilator was administrated to assist ventilation.Urine gas chromatography/mass spectrometry (GC/MS) analysis showed increases of lactic acid,3-hydroxy acid,3-tiglyl glycine,methylcitric acid,and ethylene lactic acid.Serum MS/MS analysis showed that the concentrations of propionyl camitine and 3-hydroxyisovaleryl carnitine were increase obviously.The serum biotinase level was significantly decrease to 0.076 pmol/(min·mm3).The diagnosis of BTD was confirmed.After supplementation biotin,40 mg/d,the ventilator was successfully weaned on the third day,the child walked again after 2 weeks,and the rash was vanished.After 3 weeks,the head MRI showed disappearance of the original lesion,and there was no abnormal in spinal cord.The BTD gene detected by PCR direct sequencing showed a heterozygosis mutation of T172T/C in the second exon and a homozygous mutation of T1413C in the fourth exon,which was confirmed as a pathogenic mutation by pedigree verification and database query.After discharge,the oral administration of biotin 20 mg/d continued,and no abnormality was found in 2 years of follow-up.Conclusions The manifestations of BTD are complex and diverse.The analysis of urine GC/MS and serum MS/MS can assist the diagnosis.The determination of biotinase activity and gene detection of BTD can further confirm the diagnosis.Timely biotin supplementation has significant treatment efficacy.