Distonías primarias respondedoras a levodopa (DRD): búsqueda sistemática en Latinoamérica / Dopa-responsive dystonia (DRD): systematic search in Latin America

RESUMEN Las distonías que responden a levodopa (DRD, siglas en inglés) abarcan un grupo de distonías primarias, causadas por deficiencias enzimáticas en la vía metabólica de las aminas y, por definición, comparten como característica principal su respuesta favorable y sostenida a levodopa. Existen hasta seis genes asociados a DRD, siendo el gen GCH1 el más frecuentemente involucrado. La presentación típica de esta entidad se caracteriza por su aparición en la niñez, distonía de inicio en miembros inferiores con fluctuación diurna, leve parkinsonismo y respuesta clara a dosis bajas de levodopa. Se incluye una búsqueda sistemática de la literatura con casos de DRD publicados en Latinoamérica.

SUMMARY Dopa-responsive dystonia (DRD) encompasses a heterogenous group of primary dystonias, caused by enzymatic deficiencies across the amines pathway and, by definition, show as their main characteristic a favorable and sustained response to levodopa. There are up to 6 genes associated with DRD, including pathogenic variants of the GCH1 gene as the most frequently involved. The typical presentation of DRD is characterized by start in childhood, lower limb-onset dystonia with daytime fluctuation, mild parkinsonism, and a sustained response to low doses of levodopa. A systematic literature search on DRD reported cases in Latin America is presented.

Clinical analysis of nine infants with tyrosine hydroxylase deficiency / 中华神经科杂志

Objective:To explore the clinical characteristics of children with tyrosine hydroxylase deficiency (THD) in order to recognize this disease early as to optimize the treatment to improve the prognosis.Methods:A retrospective analysis was done on the clinical data of nine children with THD who were diagnosed at the Children′s Hospital of Fudan University from May 2018 to May 2020, including name, gender, age, age of onset, age of presentation, age of diagnosis, clinical manifestations, head imaging, tyrosine hydroxylase gene mutation, treatment, follow-up, and other results, which were classified according to Willemsen′s method, and the clinical characteristics were summarized and a literature review was carried out.Results:There were five males and four females with the age at onset ranged from newborn to two years and six months (median three months). The duration of diagnosis ranged from four months to five years and seven months (median nine months). The presenting symptom was motor retardation in seven cases. Clinical symptoms included hypokinesia in eight cases, limb dystonia in five cases, truncal hypotonia in four cases, dysphagia/dysarthria in four cases, oculogyric crises in four cases, tremor in three cases, rigidity in three cases, mask faces in three cases, bilateral ptosis in two cases, hypersalivation/sweating in two cases, diurnal fluctuation in two cases, myoclonic jerks in one case, and status dystonicus in one case. Cranial magnetic resonance imaging was normal in seven cases and non-specific in two cases (backward myelination in one case and bilateral ventricle enlargement and decreased white matter in another one). Eight tyrosine hydroxylase gene variants were found, including four missense variants, two frameshift variants, one shear variants and one nonsense variant, as well as three novel variants [c.1505_1518dup (p.R507Afs *23), c.1128_1138del (p.Q377Gfs *12), c.1058A>G(p.H353R)]. All patients were treated with levodopa and benserazide hydrochloride tables. The initial and maintenance doses of type A were 1.7-8.3 mg·kg -1·d -1 and 4.5-20.0 mg·kg -1·d -1, respectively. The initial and maintenance doses of type B were 1.7-12.5 mg·kg -1·d -1 and 4.6-12.0 mg·kg -1·d -1, respectively. In type A, four patients had dyskinesis which was relieved by decreasing the dose or maintaining the same dose of levodopa. One case of type B had dyskinesis which was self-resolving. Conclusions:Although the clinical manifestations of this disease are varied, the initial symptoms in children with onset within the first year of life are mostly hypokinesia, truncal hypotonia, and dystonia in limbs. It is recommended that children with THD, regardless of clinical type, should start at the minimum dose for easy segmentation in the range of 1.0-5.0 mg·kg -1·d -1, and the maintenance dose can be adjusted according to the individual response of the child. The incidence of dyskinesia of this disease is not low, but most can be treated by decreasing the initial dose and delaying the dosage rate.

Analysis of a Pedigree with Dopa-responsive Dystonia Caused by Novel Mutation of TH Gene / 中山大学学报(医学科学版)

@#【Objective】 To study the mutation characteristics of Tyrosine hydroxyls（TH） gene in a pedigree with dopa-responsive dystonia（DRD）. 【Methods】 Extraction of genomic DNA from peripheral blood of a proband and his parents and two sisters using high- throughput sequencing （NGS） method were detected on 256 known pathogenicity genes associated with dystonia and dyskinesia.【Results】Mutations on tyrosine hydroxylase（TH）gene in the exon 14 and exon 9 were detected in the proband and his eldest sister in this pedigree. They had a complex heterozygosity of c.1481C > T（p.Thr494Met）and c.943G >A（p.Gly315Ser），and one heterozygous mutation was carried by parents respectively. The mutation was not detected in his second sister and 50 people with normal phenotype controls. 【Conclusion】 The mutations of TH gene c. 1481C > T（p.Thr494Met）and c. 943G > A（p.Gly315Ser）led to the gene abnormality in DRD family，and a new mutation of TH gene was found，which expanded the relationship between DRD genotype and clinical phenotype. It is vital that early accurate diagnosis and treatment of DRD is the key to improve prognosis.

Clinical characteristics and genetic analysis of patients with autosomal recessive dopa-responsive dystonia / 中华实用儿科临床杂志

Objective@#To analyze the clinical characteristics and gene mutation of autosomal recessive dopa-responsive dystonia(AR-DRD), and to explore its therapeutic effect, follow-up findings and molecular genetic me-chanism.@*Methods@#The whole exome sequencing, which based on next-generation sequencing, was performed in 6 movement-disordered patients who denied family history at the outpatient clinic of Children′s Hospital Affiliated to Capital Institute of Pediatrics from April 2016 to September 2017.The mutations identified in probands were then confirmed in probands and their parents by Sanger sequencing in order to analyze the cause of mutations.@*Results@#(1)Clinical features: the onset of 6 patients was around infancy, complicated with muscle weakness and abnormal muscle tone.(2)Gene mutation analysis: All 6 patients carried TH gene mutations.Five patients were of complex heterozygosis mutations, 1 patient was of homozygosis mutation.Five mutations were detected: c.605 G>A, c.601 C>T, c.364C>T, c.1412_1413insCCCCCAGGCCGTGC and c. 646G>A.(3)Therapeutic effect: all 6 patients achieved improvement of motor function after dopamine treatment, and they presented the different degrees of improvement in muscle tone and muscle strength.@*Conclusions@#The AR-DRD patients who carried c. 605 G>A mutation have a good therapeutic effect treated with L-Dopamine.This mutation may be a common mutation site of mild to moderate defective AR-DRD at home and abroad.The frameshift mutation c. 1412_1413insCCCCCAGGCCGTGC is a new TH gene pathogenicity mutation site discovered by this study.

Clinical characteristics and genetic analysis of patients with autosomal recessive dopa-responsive dystonia / 中华实用儿科临床杂志

Objective To analyze the clinical characteristics and gene mutation of autosomal recessive doparesponsive dystonia(AR-DRD),and to explore its therapeutic effect,follow-up findings and molecular genetic mechanism.Methods The whole exome sequencing,which based on next-generation sequencing,was performed in 6 movement-disordered patients who denied family history at the outpatient clinic of Children's Hospital Affiliated to Capital Institute of Pediatrics from April 2016 to September 2017.The mutations identified in probands were then confirmed in probands and their parents by Sanger sequencing in order to analyze the cause of mutations.Results (1) Clinical features:the onset of 6 patients was around infancy,complicated with muscle weakness and abnormal muscle tone.(2) Gene mutation analysis:All 6 patients carried TH gene mutations.Five patients were of complex heterozygosis mutations,1 patient was of homozygosis mutation.Five mutations were detected:c.605 G ＞ A,c.601 C ＞ T,c.364C ＞T,c.1412_1413insCCCCCAGGCCGTGC and c.646G ＞ A.(3) Therapeutic effect:all 6 patients achieved improvement of motor function after dopamine treatment,and they presented the different degrees of improvement in muscle tone and muscle strength.Conclusions The AR-DRD patients who carried c.605 G ＞ A mutation have a good therapeutic effect treated with L-Dopamine.This mutation may be a common mutation site of mild to moderate defective AR-DRD at home and abroad.The frameshift mutation c.1412_1413insCCCCCAGGCCGTGC is a new TH gene pathogenicity mutation site discovered by this study.

Clinical and genetic study on 5 children with dopa-responsive dystonia due to tyrosine hydroxylase deficiency / 中华实用儿科临床杂志

Objective To explore the clinical characteristics,gene mutations,diagnosis and treatment of chil-dren with dopa-responsive dystonia due to tyrosine hydroxylase(TH)deficiency.Methods Five patients(3 boys and 2 girls)with dopa-responsive dystonia due to TH deficiency were diagnosed and followed up from January 2002 to October 2017.The clinical manifestations,laboratory findings,treatment and TH gene mutations associated with TH defi-ciency were analyzed.Results Five patients came from different families.They had the onset at the age of 8 months to 20 months with dystonia,paroxysmal muscular hypertonia and normal intelligence or mild mental retardation.All of them had been misdiagnosed as cerebral palsy.Two cases with floppy limbs presented with fatigue and tremor.One case with floppy limbs presented with seizures. Complex heterozygous mutations were found in TH gene of all patients,which helped to confirm the diagnosis.Eight mutations were identified in TH gene.Six of them were reported.Two novel muta-tions,c.1077C>A(p.C359X)and c.1228C>T(p.R410C)were detected.After the treatment by levodopa[2.2-5.4 mg/(kg·d)],significant improvement was observed.Three patients recovered their intellectual and motor activi-ties.Two patients were dramatically improved but with slightly uncoordinated movements.Conclusion The patients of dopa-responsive dystonia due to TH deficiency usually have the onset around one year of age with almost normal inte-lligence,motor retardation and dystonia.The patients are likely misdiagnosed as cerebral palsy.The treatment with levo-dopa can dramatically improve the symptoms.The etiological diagnosis is very important.

A Case of Dopa-responsive Dystonia with a Mutation in the GCH1 Gene Misdiagnosed as Cerebral Palsy for 2 Years / 대한소아신경학회지

Dopa-responsive dystonia (DRD) is characterized by lower limb-onset, diurnally fluctuating dystonia and dramatic and sustained response to levodopa treatment. Segawa disease, an autosomal dominant deficiency of guanosine triphosphate cyclohydrolase 1 (encoded by GCH1) is the most common and well-known condition manifesting as DRD. However, similar clinical manifestations can be seen in individuals with deficiencies of other enzymes that are involved in the biosynthesis of dopamine. We describe the case of an 11-year-old girl who presented with abnormal gait, which had initially begun 2 years back. The patient showed diurnally fluctuating dystonia in both legs. She was able to walk without support in the morning, but was unable to stand without support in the evening. She had been diagnosed as having spastic cerebral palsy and had been managed with physical therapy at a local rehabilitation clinic. The patient had been healthy until the development of dystonia, and did not have a history of perinatal problems or developmental delay. Routine hematologic and biochemical test results were normal. Brain magnetic resonance imaging and electroencephalography showed no abnormalities. When levodopa was administered, the patient's abnormal gait dramatically improved 1 hour after receiving the medication. Genetic testing for the GCH1 gene revealed a missense mutation (c.293C>T [p.A98V]) that has previously been reported in patients with DRD. This case demonstrated that a levodopa trial is vital for accurate and early diagnosis of DRD in patients with dystonia resulting from an unknown cause.

A novel pathological mutation of tyrosine hydroxylase gene in dopa-responsive dystonia / 中华神经科杂志

Objective To explore the clinical characteristics and gene mutation in a patient clinically diagnosed as dopa-responsive dystonia (DRD) without family history.Methods The clinical characteristics of a patient clinically diagnosed as DRD without family history were collected and molecular and bioinformatic analyses were performed.Results The patient demonstrated as type A tyrosine hydroxylase deficiency and a compound heterozygous mutation of tyrosine hydroxylase (TH) gene was found,including a known nonsense mutation,c.457C＞T and a novel missense mutation,c.734G＞T that was probably pathologically predicted by bioinformatic analysis.Conclusion c.734G＞T may be a novel pathological mutation of TH gene.

Dopa-responsive Dystonia Misdiagnosed as Cerebral Palsy and Hereditary Spastic Paraplegia 2 Cases: Two cases report

Dystonia is a movement disorder caused by involuntary, sustained muscle contractions, frequently resulting in twitching and repetitive movements or abnormal postures. Dopa-responsive dystonia (DRD) is characterized by early childhood onset, marked diurnal fluctuation of symptoms and dramatic response to levodopa. The aim of this report is to present the two cases of DRD misdiagnosed respectively as cerebral palsy and hereditary spastic paraplegia. Proper understanding of this disease entity and its treatment options are necessary for comprehensive rehabilitative management of DRD.

A novel missense mutation pattern of the GCH1 gene in dopa-responsive dystonia

Dopa-responsive dystonia (DRD) is an inherited metabolic disorder now classified as DYT5 with two different biochemical defects: autosomal dominant GTP cyclohydrolase 1 (GCH1) deficiency or autosomal recessive tyrosine hydroxylase deficiency. We report the case of a 10-years-old girl with progressive generalized dystonia and gait disorder who presented dramatic response to levodopa. The phenylalanine to tyrosine ratio was significantly higher after phenylalanine loading test. This condition had two different heterozygous mutations in the GCH1 gene: the previously reported P23L mutation and a new Q182E mutation. The characteristics of the DRD and the molecular genetic findings are discussed.

Distonia dopa-responsiva (DRD), classificada como DYT5, é um erro inato do metabolismo que pode ser causado por dois diferentes tipos de defeito bioquímico: deficiência de GTP ciclo-hidrolase 1 (GCH1) (autossômica dominante) ou de tirosina hidroxilase (autossômica recessiva). Descrevemos o caso de menina de 10 anos com distonia generalizada progressiva e alteração da marcha com importante melhora após uso de levodopa. A relação fenilalanina/tirosina estava aumentada após teste de sobrecarga com fenilalanina. O estudo molecular mostrou que o paciente apresenta uma combinação hererozigótica de mutação no gene GCH1: a já conhecida mutação P23L e uma nova mutação Q182E. Discutem-se as características da DRD e as alterações genéticas possíveis.

A Case of Dopa-Responsive Dystonia, Segawa Disease / 대한소아신경학회지

Segawa disease, hereditary progressive dystonia with marked diurnal fluctuations or defined dopa-responsive dystonia has age-dependent clinical courses, which are characterized with marked progression in the first one and half decades, its subsiding in the third decade and almost stationary courses after the fourth decade. Also, it has characteristic diurnally fluctuating symptoms, aggravated towards the evening and alleviated after sleep. This autosomally dominantly inherited dystonia is caused by abnormalities of the gene of GTP cyclohydrolase I. The heterozygotic gene's abnormality induces partial decrement of tetrahydrobiopterin and affects synthesis of tyrosine hydroxylase(TH) rather selectively. The reduction of TH induces decrement of dopamine and disfacilitates the D1 receptor-striatal direct pathway. The pathognomonic finding in biochemical examination is the decrease of neopterin in the cerebrospinal fluid(CSF). Levodopa, by replacing dopamine contents at the terminal, alleviates motor symptoms completely and the effects sustain without any side effects. We experienced a girl diagnosed as Segawa disease with typical clinical courses and a decrease of neopterin in the CSF.

Clinical View Points on Primary Dystonia and Dystonia-plus Syndrome

Dystonia is a disorder of movement caused by involuntary, sustained muscle contractions affecting one or more sites of body, frequently causing twisting and repetitive movements, or postures. Dystonic movements and postures can produce a wide range of clinical presentations. Some distinguishing clinical features of dystonia can help the appropriate diagnosis of primary dystonia. The direction of contraction is almost consistent. Action dystonia and occupational dystonia are related to a movement or task-specific movement, respectively. Sensory tricks or gestes antagonistes are usually seen in patients with dystonia. Two types of tremors can be seen in patients with dystonia: a postural and/or action tremor that resembles essential tremor and a rhythmic expression of dystonic tremor. Sometimes dystonic tremor appears to be less regular and can be associated with myoclonus. Onset age of dystonia, body distribution and etiologies are important to correct diagnosis of primary dystonia. It is well known that the age of onset has important prognostic implications. This article highlights general concepts of phenomenology, classification that are relevant for the purpose a clinical diagnosis.

Dopa-responsive Dystonia Misdiagnosed as Cerebral Plasy: A Case Report / 대한정형외과학회잡지

Dopa-responsive dystonia (DRD) is a slowly progressive dystonia with childhood onset and is characterized by marked diurnal fluctuation of symptoms, dramatic response to levodopa treatment and concurrent signs of parkinsonism. We report a 16-year-old girl diagnosed as DRD. Around the age of 11, gait disturbance was developed with equinocavovarus deformity of both feet. The plantar fasciotomy, triple arthrodesis and posterior tibialis tendon transfer for left foot with the diagnosis of cerebral palsy were done. She complained of a persistent dystonia of all extremities after operation and was successfully treated with low-dose levodopa after a diagnosis of DRD. For the accurate diagnosis and prevention of unnecessary operation, trial of levodopa is warranted in patients suspected with cerebral palsy with similar symptoms of DRD.