Ehlers-Danlos/myopathy overlap syndrome caused by a large de novo deletion in COL12A1.

Autosomal dominant and recessive mutations in COL12A1 cause the Ehlers-Danlos/myopathy overlap syndrome. Here, we describe a boy with fetal hypokinesia, severe neonatal weakness, striking hyperlaxity, high arched palate, retrognathia, club feet, and pectus excavatum. His motor development was initially delayed but muscle strength improved with time while hyperlaxity remained very severe causing recurrent joint dislocations. Using trio exome sequencing and a copy number variation (CNV) analysis tool, we identified an in-frame de novo heterozygous deletion of the exons 45 to 54 in the COL12A1 gene. Collagen XII immunostaining on cultured skin fibroblasts demonstrated intracellular retention of collagen XII, supporting the pathogenicity of the deletion. The phenotype of our patient is slightly more severe than other cases with dominantly acting mutations, notably with the presence of fetal hypokinesia. This case highlights the importance of CNVs analysis in the COL12A1 gene in patients with a phenotype suggesting Ehlers-Danlos/myopathy overlap syndrome.

Identifying dominant-negative actions of a dopamine transporter variant in patients with parkinsonism and neuropsychiatric disease.

Dysfunctional dopaminergic neurotransmission is central to movement disorders and mental diseases. The dopamine transporter (DAT) regulates extracellular dopamine levels, but the genetic and mechanistic link between DAT function and dopamine-related pathologies is not clear. Particularly, the pathophysiological significance of monoallelic missense mutations in DAT is unknown. Here, we use clinical information, neuroimaging, and large-scale exome-sequencing data to uncover the occurrence and phenotypic spectrum of a DAT coding variant, DAT-K619N, which localizes to the critical C-terminal PSD-95/Discs-large/ZO-1 homology-binding motif of human DAT (hDAT). We identified the rare but recurrent hDAT-K619N variant in exome-sequenced samples of patients with neuropsychiatric diseases and a patient with early-onset neurodegenerative parkinsonism and comorbid neuropsychiatric disease. In cell cultures, hDAT-K619N displayed reduced uptake capacity, decreased surface expression, and accelerated turnover. Unilateral expression in mouse nigrostriatal neurons revealed differential effects of hDAT-K619N and hDAT-WT on dopamine-directed behaviors, and hDAT-K619N expression in Drosophila led to impairments in dopamine transmission with accompanying hyperlocomotion and age-dependent disturbances of the negative geotactic response. Moreover, cellular studies and viral expression of hDAT-K619N in mice demonstrated a dominant-negative effect of the hDAT-K619N mutant. Summarized, our results suggest that hDAT-K619N can effectuate dopamine dysfunction of pathological relevance in a dominant-negative manner.

An identical-by-descent novel splice-donor variant in PRUNE1 causes a neurodevelopmental syndrome with prominent dystonia in two consanguineous Sudanese families.

PRUNE1 is linked to a wide range of neurodevelopmental and neurodegenerative phenotypes. Multiple pathogenic missense and stop-gain PRUNE1 variants were identified in its DHH and DHHA2 phosphodiesterase domains. Conversely, a single splice alteration was previously reported. We investigated five patients from two unrelated consanguineous Sudanese families with an inherited severe neurodevelopmental disorder using whole-exome sequencing coupled with homozygosity mapping, segregation, and haplotype analysis. We identified a founder haplotype transmitting a homozygous canonical splice-donor variant (NM_021222.3:c.132+2T > C) in intron 2 of PRUNE1 segregated with the phenotype in all the patients. This splice variant possibly results in an in-frame deletion in the DHH domain or premature truncation of the protein. The phenotypes of the affected individuals showed phenotypic similarities characterized by remarkable pyramidal dysfunction and prominent extrapyramidal features (severe dystonia and bradykinesia). In conclusion, we identified a novel founder variant in PRUNE1 and corroborated abnormal splicing events as a disease mechanism in PRUNE1-related disorders. Given the phenotypes' consistency coupled with the founder effect, canonical and cryptic PRUNE1 splice-site variants should be carefully evaluated in patients presenting with prominent dystonia and pyramidal dysfunction.

Genetic characterization of a cohort with familial parkinsonism and cognitive-behavioral syndrome: A Next Generation Sequencing study.

OBJECTIVE: To perform the genetic characterization of a cohort with familial parkinsonism and cognitive-behavioral syndrome. METHODS: A Next Generation Sequencing - based targeted sequencing of 32 genes associated to various neurodegenerative phenotypes, plus a screening for SNCA Copy Number Variations and C9orf72 repeat expansion, was applied in a cohort of 85 Italian patients presenting with parkinsonism and cognitive and/or behavioral syndrome and a positive familial history for any neurodegenerative disorder (i.e., dementia, movement disorders, amyotrophic lateral sclerosis). RESULTS: Through this combined genetic approach, we detected potentially relevant genetic variants in 25.8% of patients with familial parkinsonism and cognitive and/or behavioral syndrome. Peculiar phenotypes are described (Cortico-basal syndrome with APP, Posterior Cortical Atrophy with GBA, Progressive Supranuclear Palsy-like with GRN, Multiple System Atrophy with TARDBP). The majority of patients presented a rigid-bradykinetic parkinsonian syndrome, while rest tremor was less common. Myoclonic jerks, pyramidal signs, dystonic postures and vertical gaze disturbances were more frequently associated with the presence of a pathogenic variant in one of the tested genes. CONCLUSIONS: Given the syndromic approach adopted in our study, we were able to provide a detailed clinical description of patients beyond the boundaries of specific clinical diagnoses and describe peculiar phenotypes. This observation further supports the knowledge that genetic disorders present phenotypic overlaps across different neurodegenerative syndromes, highlighting the limitations of current clinical diagnostic criteria defining sharp boundaries between distinct conditions.

Prediction of age at onset in Parkinson's disease using objective specific neuroimaging genetics based on a sparse canonical correlation analysis.

The age at onset (AAO) is an important determinant in Parkinson's disease (PD). Neuroimaging genetics is suitable for studying AAO in PD as it jointly analyzes imaging and genetics. We aimed to identify features associated with AAO in PD by applying the objective-specific neuroimaging genetics approach and constructing an AAO prediction model. Our objective-specific neuroimaging genetics extended the sparse canonical correlation analysis by an additional data type related to the target task to investigate possible associations of the imaging-genetic, genetic-target, and imaging-target pairs simultaneously. The identified imaging, genetic, and combined features were used to construct analytical models to predict the AAO in a nested five-fold cross-validation. We compared our approach with those from two feature selection approaches where only associations of imaging-target and genetic-target were explored. Using only imaging features, AAO prediction was accurate in all methods. Using only genetic features, the results from other methods were worse or unstable compared to our model. Using both imaging and genetic features, our proposed model predicted the AAO well (r = 0.5486). Our findings could have significant impacts on the characterization of prodromal PD and contribute to diagnosing PD early because genetic features could be measured accurately from birth.

Iroquois Homeobox Protein 2 Identified as a Potential Biomarker for Parkinson's Disease.

The diagnosis of Parkinson's disease (PD) is initiated after the occurrence of motor symptoms, such as resting tremors, rigidity, and bradykinesia. According to previous reports, non-motor symptoms, notably gastrointestinal dysfunction, could potentially be early biomarkers in PD patients as such symptoms occur earlier than motor symptoms. However, connecting PD to the intestine is methodologically challenging. Thus, we generated in vitro human intestinal organoids from PD patients and ex vivo mouse small intestinal organoids from aged transgenic mice. Both intestinal organoids (IOs) contained the human LRRK2 G2019S mutation, which is the most frequent genetic cause of familial and sporadic PD. By conducting comprehensive genomic comparisons with these two types of IOs, we determined that a particular gene, namely, Iroquois homeobox protein 2 (IRX2), showed PD-related expression patterns not only in human pluripotent stem cell (PSC)-derived neuroectodermal spheres but also in human PSC-derived neuronal cells containing dopaminergic neurons. We expected that our approach of using various cell types presented a novel technical method for studying the effects of multi-organs in PD pathophysiology as well as for the development of diagnostic markers for PD.

Evolution of prodromal parkinsonian features in a cohort of GBA mutation-positive individuals: a 6-year longitudinal study.

OBJECTIVES: GBA1 mutations are a frequent risk factor for Parkinson disease (PD). The aim of this study is to evaluate clinical features in a group of GBA1 mutation-positive individuals over a 6-year follow-up. METHODS: This is a longitudinal study on a cohort of GBA1-positive carriers. We enrolled 31 patients with Gaucher disease type 1 (GD), 29 GBA1 heterozygous carriers (Het GBA group) and 30 controls (HC) at baseline and followed them for 6 years. We assessed baseline motor and non-motor signs of PD in all subjects using clinical questionnaires and scales (reduced Unified Multiple System Atrophy Rating Scale (UMSARS), Montreal Cognitive assessment (MoCA), University of Pennsylvania Smell Identification Test (UPSIT), REM Sleep Behavior Disorder screening questionnaire (RBDsq), Movement Disorders Society Unified Parkinson's Disease Rating Scale motor subscale (MDS-UPDRS III) and Beck Depression Inventory (BDI). We repeated these at the 6-year follow-up alongside venous blood sampling for measurement of glucocerebrosidase enzymatic activity (GCase). We explored whether the GCase activity level was altered in leucocytes of these subjects and how it was related to development of PD. RESULTS: We observed a significant worsening in UMSARS, RBDsq, MDS-UPDRS III and BDI scores at the 6-year follow-up compared with baseline in both the GD and Het GBA groups. Intergroup comparisons showed that GD subjects had significantly worse scores in UPSIT, UMSARS, MoCA and MDS-UPDRS III than HC, while Het GBA displayed worse outcomes in UPSIT and MDS-UPDRS III compared with HC. In GBA1 mutation-positive individuals (Het GBA and GD), an UPSIT score of 23 at baseline was correlated with worse outcome at 6 years in UPSIT, MoCA, MDS-UPDRS III and BDI. CONCLUSION: In this 6-year-long longitudinal study, GBA1 mutation-positive subjects showed a worsening in motor and non-motor prodromal PD features.

Familial NEDD4L variant in periventricular nodular heterotopia and in a fetus with hypokinesia and flexion contractures.

BACKGROUND: Mutations in the HECT domain of NEDD4L have recently been identified in a cohort of eight patients with a syndromic form of bilateral periventricular nodular heterotopia (PVNH) in association with neurodevelopmental delay, cleft palate, and toe syndactyly (PVNH7). METHODS: Case report based on NGS sequencing. RESULTS: Here, we describe a girl with a novel heterozygous NEDD4L missense variant, p.Tyr679His, and characteristic clinical findings, including bilateral periventricular nodular heterotopia, cleft palate and mild toe syndactyly. Molecular testing from peripheral blood identified the healthy father to carry the NEDD4L variant in mosaic state. Notably, a previous pregnancy of the couple had been terminated due to a complex fetal developmental disorder, including hypokinesia and flexion contractures. Upon review, this affected fetus was also shown to carry the familial NEDD4L variant. CONCLUSION: Our findings may suggest a broader spectrum of NEDD4L-associated phenotypes, including severe prenatal neurodevelopmental manifestations, which might represent yet another genetic form of fetal hypokinesia with flexion contractures.

Loss-of-function mutations in SCN4A cause severe foetal hypokinesia or 'classical' congenital myopathy.

Congenital myopathies are a clinically and genetically heterogeneous group of muscle disorders characterized by congenital or early-onset hypotonia and muscle weakness, and specific pathological features on muscle biopsy. The phenotype ranges from foetal akinesia resulting in in utero or neonatal mortality, to milder disorders that are not life-limiting. Over the past decade, more than 20 new congenital myopathy genes have been identified. Most encode proteins involved in muscle contraction; however, mutations in ion channel-encoding genes are increasingly being recognized as a cause of this group of disorders. SCN4A encodes the α-subunit of the skeletal muscle voltage-gated sodium channel (Nav1.4). This channel is essential for the generation and propagation of the muscle action potential crucial to muscle contraction. Dominant SCN4A gain-of-function mutations are a well-established cause of myotonia and periodic paralysis. Using whole exome sequencing, we identified homozygous or compound heterozygous SCN4A mutations in a cohort of 11 individuals from six unrelated kindreds with congenital myopathy. Affected members developed in utero- or neonatal-onset muscle weakness of variable severity. In seven cases, severe muscle weakness resulted in death during the third trimester or shortly after birth. The remaining four cases had marked congenital or neonatal-onset hypotonia and weakness associated with mild-to-moderate facial and neck weakness, significant neonatal-onset respiratory and swallowing difficulties and childhood-onset spinal deformities. All four surviving cohort members experienced clinical improvement in the first decade of life. Muscle biopsies showed myopathic features including fibre size variability, presence of fibrofatty tissue of varying severity, without specific structural abnormalities. Electrophysiology suggested a myopathic process, without myotonia. In vitro functional assessment in HEK293 cells of the impact of the identified SCN4A mutations showed loss-of-function of the mutant Nav1.4 channels. All, apart from one, of the mutations either caused fully non-functional channels, or resulted in a reduced channel activity. Each of the affected cases carried at least one full loss-of-function mutation. In five out of six families, a second loss-of-function mutation was present on the trans allele. These functional results provide convincing evidence for the pathogenicity of the identified mutations and suggest that different degrees of loss-of-function in mutant Nav1.4 channels are associated with attenuation of the skeletal muscle action potential amplitude to a level insufficient to support normal muscle function. The results demonstrate that recessive loss-of-function SCN4A mutations should be considered in patients with a congenital myopathy.

SIL1-related Marinesco-Sjoegren syndrome (MSS) with associated motor neuronopathy and bradykinetic movement disorder.

Marinesco-Sjoegren syndrome (MSS) is a recessively inherited multisystem disorder caused by mutations in SIL1 and characterized by cerebellar atrophy with ataxia, cataracts, a skeletal muscle myopathy, and variable degrees of developmental delay. Pathogenic mechanisms implicated to date include mitochondrial, nuclear envelope and lysosomal-autophagic pathway abnormalities. Here we present a 5-year-old girl with SIL1-related MSS and additional unusual features of an associated motor neuronopathy and a bradykinetic movement disorder preceding the onset of ataxia. These findings suggest that an associated motor neuronopathy may be part of the phenotypical spectrum of SIL1-related MSS and should be actively investigated in genetically confirmed cases. The additional observation of a bradykinetic movement disorder suggests an intriguing continuum between neurodevelopmental and neurodegenerative multisystem disorders intricately linked in the same cellular pathways.

Echogenicity of basal ganglia structures in different Huntington's disease phenotypes.

In Huntington's disease (HD), a neurodegenerative-inherited disease, chorea as the typical kind of movement disorder is described. Beside chorea, however, all other kinds of movement disturbances, such as bradykinesia, dystonia, tremor or myoclonus can occur. Aim of the current study was to investigate alterations in the echogenicity of basal ganglia structures in different Huntington's disease phenotypes. 47 patients with manifest and genetically confirmed HD were recruited. All participants underwent a thorough neurological examination. According to a previously described method, classification into predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes was performed depending on subscores of the Unified Huntington's Disease Rating Scale. In addition, findings in juvenile HD were compared to adult HD. Transcranial sonography was performed by investigators blinded to clinical classification. There were no significant differences in basal ganglia echogenicities between the three phenotypes. Size of echogenic area of substantia nigra (SN) correlated positively with CAG repeat and bradykinesia subscore, and negatively with age of onset and chorea subscore. Comparing juvenile and adult HD subtypes, SN hyperechogenicity was significantly more often detectable in the juvenile form (100 vs. 29.3 %, p = 0.002). Regarding echogenicity of caudate or lentiform nuclei, no significant differences were detected. HD patients with the juvenile variant exhibit marked hyperechogenicity of substantia nigra. No significant differences in basal ganglia echogenicities between predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes were detected.

Ultrasound-based motion analysis demonstrates bilateral arm hypokinesia during gait in heterozygous PINK1 mutation carriers.

Carriers of a single heterozygous PINK1 (PTEN-induced putative kinase 1) gene mutation provide an ideal opportunity to study the development of parkinsonian motor signs from the very beginning. Measuring tools that reliably represent mild motor symptoms could also facilitate the assessment of future neuroprotective therapies and early diagnosis of Parkinson's disease (PD). We investigated nine family members carrying a heterozygous PINK1 mutation in comparison with 25 age-matched healthy controls. Arm kinematics were quantified during treadmill walking at four different speeds using ultrasound-based motion analysis. Heterozygous PINK1 mutation carriers showed a bilateral reduction of arm swing amplitudes (P = 0.003) and arm anteversion (P = 0.001), which was more pronounced on the predominantly affected body side but also was present, albeit to a lesser degree, contralaterally (amplitude P = 0.01, anteversion P = 0.002, repeated measures analysis of covariance [rmANCOVA]). Single post-hoc comparisons revealed similar results for all speeds on both body sides (P < 0.05) except for 2.0 km/h on the less affected side. A single heterozygous mutation in the PINK1 gene is associated with a bilateral dopaminergic dysfunction in this family. Ultrasound-based three-dimensional motion analysis of arm swing during gait is a suitable tool to quantify even subtle hypokinesia in mildly affected PINK1 mutation carriers, which tends to be easily overlooked on the less affected body side during clinical examination. Therefore, this technique is a promising application in early stage PD and in at-risk populations for the disease.

[Tyrosine hydroxylase deficiency: a case of autosomal recessive dopa-responsive dystonia].

OBJECTIVE: To analyze the clinical characteristics of the patient with tyrosine hydroxylase deficiency, and investigate it's molecular mechanism. METHOD: The clinical characteristics of a patient with tyrosine hydroxylase deficiency were summarized and analyzed, his and his family's peripheral blood specimens were collected after informed consent was signed. All exons and the intron-exon boundaries of guanosine triphosphate hydroxylase I gene, tyrosine hydroxylase gene and sepiapterin reductase gene were examined by DNA-PCR, bi-directional sequencing. RESULT: The patient was a 3-year-old boy, presented with unexplained dystonia for 3 years, without significant impairment of intelligence. Physical examination showed limb muscle strength grade V, rigidity of extremities, hypertonicity, brisk deep tendon reflexes in limbs, without obvious abnormalities in auxiliary examination, such as brain MRI, hepatic biochemical panel, creatine kinase, and ceruloplasmin. He dramatically responded to small doses of levodopa in the follow-up for half a year. A homozygous missense change in exon 5 of TH gene, c.605G > A (p.R202H), which was a known pathogenic mutation, was found in the patient. His parents were heterozygous for the R202H mutation. CONCLUSION: The age of onset in tyrosine hydroxylase deficiency patients is usually within the first year of life. Unexplained dystonia and hypokinesia were the main clinical features of tyrosine hydroxylase deficiency. The dopa-responsive effects for some patients are so obvious that we should strengthen awareness of the disease. TH gene c.605G > A (p.R202H) may be a common type of causative mutations for the mild form at home and abroad.

Anxious, hypoactive phenotype combined with motor deficits in Gtf2ird1 null mouse model relevant to Williams syndrome.

Williams-Beuren syndrome (WBS) is a rare genetic disorder caused by a hemizygous deletion of around 28 genes on the long arm of chromosome 7 (7q11.23), characterized by a unique spectrum of behavioral impairments, including mental retardation, deficits in visuospatial constructive cognition, hypersociability, anxiety and simple phobias. Physical characteristics include dysmorphic faces, short stature, oculomotor deficits, gross and fine coordination impairments, diminished control of balance and mild extrapyramidal signs as well as gait abnormalities resembling gait hypokinesia. Genes near the distal deletion breakpoint appear to contribute most to the WBS cognitive and behavioral profile and include the GTF family of transcription factors: GTF2I, GTF2IRD1, GTF2IRD2. We have previously shown that heterozygous deletions of GTF2IRD1 in humans and homozygous deletion in mice contributes to craniofacial abnormalities. Here we show an important role of this gene in motor coordination and anxiety ascertained from extensive behavioral mouse phenotyping. Gtf2ird1 null mice showed lower body weight, decreased spontaneous and circadian locomotor activity, diminished motor coordination and strength, gait abnormalities, increased anxiety and an elevated endocrinological response to stress. Gtf2ird1 heterozygous mice displayed lower body weight and decreased circadian activity, but only minor motor coordination and anxiety-related behavioral dysfunctions. Our study strongly supports a role for GTF2IRD1 in the motoric and anxiety-related abnormalities seen in Williams-Beuren syndrome, and suggests basal ganglia and potentially cerebellar abnormalities in Gtf2ird1 mice.

A de novo deletion of 20q11.2-q12 in a boy presenting with abnormal hands and feet, retinal dysplasia, and intractable feeding difficulty.

Proximal interstitial deletions involving 20q11-q12 are very rare. Only two cases have been reported. We describe another patient with 20q11.21-q12 deletion. We precisely mapped the 6.5-Mb deletion and successfully determined the deletion landmarks at the nucleotide level. Common clinical features among the three cases include developmental delay, intractable feeding difficulties with gastroesophageal reflux, and facial dysmorphism including triangular face, hypertelorism, and hypoplastic alae nasi, indicating that the 20q11.2-q12 deletion can be a clinically recognizable syndrome. This is also supported by the fact that the three deletions overlap significantly. In addition, unique features such as arthrogryposis/fetal akinesia (hypokinesia) deformation and retinal dysplasia are recognized in the patient reported herein.

Large-scale screening of the Gaucher's disease-related glucocerebrosidase gene in Europeans with Parkinson's disease.

Pathogenic variants in the glucocerebrosidase gene (GBA) encoding the enzyme deficient in Gaucher's disease (GD) are associated with Parkinson's disease (PD). To investigate the sequence variants, their association with PD and the related phenotypes in a large cohort of European, mostly French, patients and controls, we sequenced all exons of GBA in 786 PD patients from 525 unrelated multiplex families, 605 patients with apparently sporadic PD and 391 ethnically matched controls. GBA mutations were significantly more frequent (odds ratio=6.98, 95% confidence interval 2.54-19.21; P=0.00002) in the PD patients (76/1130=6.7%) than in controls (4/391=1.0%) and in patients with family histories of PD (8.4%) than in isolated cases (5.3%). Twenty-eight different mutations were identified in patient and control groups, including seven novel variants. N370S and L444P accounted for 70% of all mutant alleles in the patient group. PD patients with GBA mutations more frequently had bradykinesia as the presenting symptom and levodopa-induced dyskinesias. The phenotype was similar in patients with one, two or complex GBA mutations, although the two patients with c.1263del+RecTL and N370S/RecΔ55 mutations had signs of GD. Segregation analyses in 21 multiplex families showed that 17% of the affected relatives did not carry GBA mutations found in the given family, indicating heterogeneity of the aetiology, but 46% of the unaffected relatives were GBA mutation carriers. These genotype and clinical analyses on the largest homogeneous sample of European patients studied to date confirmed that GBA mutations are the most common genetic risk factor for PD, particularly in familial forms.

Regulation of parkinsonian motor behaviours by optogenetic control of basal ganglia circuitry.

Neural circuits of the basal ganglia are critical for motor planning and action selection. Two parallel basal ganglia pathways have been described, and have been proposed to exert opposing influences on motor function. According to this classical model, activation of the 'direct' pathway facilitates movement and activation of the 'indirect' pathway inhibits movement. However, more recent anatomical and functional evidence has called into question the validity of this hypothesis. Because this model has never been empirically tested, the specific function of these circuits in behaving animals remains unknown. Here we report direct activation of basal ganglia circuitry in vivo, using optogenetic control of direct- and indirect-pathway medium spiny projection neurons (MSNs), achieved through Cre-dependent viral expression of channelrhodopsin-2 in the striatum of bacterial artificial chromosome transgenic mice expressing Cre recombinase under control of regulatory elements for the dopamine D1 or D2 receptor. Bilateral excitation of indirect-pathway MSNs elicited a parkinsonian state, distinguished by increased freezing, bradykinesia and decreased locomotor initiations. In contrast, activation of direct-pathway MSNs reduced freezing and increased locomotion. In a mouse model of Parkinson's disease, direct-pathway activation completely rescued deficits in freezing, bradykinesia and locomotor initiation. Taken together, our findings establish a critical role for basal ganglia circuitry in the bidirectional regulation of motor behaviour and indicate that modulation of direct-pathway circuitry may represent an effective therapeutic strategy for ameliorating parkinsonian motor deficits.

Tyrosine hydroxylase deficiency: a treatable disorder of brain catecholamine biosynthesis.

Tyrosine hydroxylase deficiency is an autosomal recessive disorder resulting from cerebral catecholamine deficiency. Tyrosine hydroxylase deficiency has been reported in fewer than 40 patients worldwide. To recapitulate all available evidence on clinical phenotypes and rational diagnostic and therapeutic approaches for this devastating, but treatable, neurometabolic disorder, we studied 36 patients with tyrosine hydroxylase deficiency and reviewed the literature. Based on the presenting neurological features, tyrosine hydroxylase deficiency can be divided in two phenotypes: an infantile onset, progressive, hypokinetic-rigid syndrome with dystonia (type A), and a complex encephalopathy with neonatal onset (type B). Decreased cerebrospinal fluid concentrations of homovanillic acid and 3-methoxy-4-hydroxyphenylethylene glycol, with normal 5-hydroxyindoleacetic acid cerebrospinal fluid concentrations, are the biochemical hallmark of tyrosine hydroxylase deficiency. The homovanillic acid concentrations and homovanillic acid/5-hydroxyindoleacetic acid ratio in cerebrospinal fluid correlate with the severity of the phenotype. Tyrosine hydroxylase deficiency is almost exclusively caused by missense mutations in the TH gene and its promoter region, suggesting that mutations with more deleterious effects on the protein are incompatible with life. Genotype-phenotype correlations do not exist for the common c.698G>A and c.707T>C mutations. Carriership of at least one promotor mutation, however, apparently predicts type A tyrosine hydroxylase deficiency. Most patients with tyrosine hydroxylase deficiency can be successfully treated with l-dopa.

[Cytogenetic characteristics of human blood lymphocytes in vivo in a 120-day bedrest study].

Effects of 120-d bed rest on chromosomal aberration rate were studied in lymphocytes of human peripheral blood in vivo. Chromosomal analysis revealed statistically significant increases in dicentrics and paired acentric fragments in blood lymphocytes of human test-subjects.