A novel Met116Thr mutation in the GDAP1 gene in a Polish family with the axonal recessive Charcot-Marie-Tooth type 4 disease

Mutations in the gene coding for ganglioside-induced differentiation-associated protein-1 (GDAP1), which maps to chromosome 8q21, have been described in families with autosomal recessive Charcot-Marie-Tooth disease (CMT4A). Interestingly, some mutations in the GDAP1 gene have been reported in the demyelinating form of CMT1 disease, whereas others were found in patients with the axonal type of CMT disease. So far, 23 mutations in the GDAP1 gene have been reported in patients of different ethnic origins. In this study we report a novel mutation Met116Thr in the GDAP1 gene identified in a three generation Polish family with axonal CMT4.     

A novel mutation (Thr116Ile) in the presenilin 1 gene in a patient with early-onset Alzheimer''s disease

We report a novel presenilin 1 (PSN1) mutation (Thr116Ile) in a woman with early onset Alzheimer's disease (AD). This mutation was not found in 100 healthy controls, indicating that this is not a common polymorphism. The patient presented with forgetfulness at age 45, followed over the next 3 years by a worsening of the memory loss and frequent episodes of confusion and spatial disorientation. Neuroimaging studies were consistent with AD. The analysis of the family's pedigree showed that the proband was apparently the only member affected. Because the early death of several close relatives (i.e. the mother and the grandmother) and the demonstration that the father is not a mutation carrier, it is suggested that either a de novo mutation or a censor effect might have occurred. Our finding supports the indication that PSN1 mutations should be searched for in early-onset AD, particularly when a censor effect precludes a precise genetic analysis.     

A novel ABCD1 gene mutation in a Chinese-Taiwanese patient with adrenomyeloneuropathy

The ABCD1 gene mutation (previously ALD) has been reported in China, but not previously in Taiwan. This case report describes one Taiwanese patient whose clinical manifestations were compatible with adrenomyeloneuropathy. Direct sequencing for the ABCD1 gene of this patient and his mother detected a novel missense mutation, K513Q, in exon 6, the first such detected in a Taiwanese patient. Previous studies have suggested exon 6 as a possible hot segment of ABCD1 gene mutations in Chinese populations; however, most of the mutations in exon 6 presented as childhood cerebral adrenoleukodystrophy. K513Q is also the first novel mutation located within exon 6 and presenting with adult-onset adrenomyeloneuropathy in Chinese-Taiwanese.     

A novel mutation, Thr65Ala, in the MPZ gene in a patient with Charcot-Marie-Tooth type 1B disease with focally folded myelin

Charcot-Marie-Tooth type 1B disease is a demyelinating neuropathy caused by mutations in the Myelin Protein Zero gene. It is inherited in an autosomal dominant fashion. So far only a few patients with a focally folded myelin phenotype on nerve biopsy have been shown to have mutations in the Myelin Protein Zero gene. In this report we describe a Polish patient with Charcot-Marie-Tooth type 1B disease. Sural nerve biopsy demonstrated focally folded myelin. Molecular genetic analysis of the coding region of the Myelin Protein Zero gene revealed a novel mutation, Thr65Ala, in exon 2 of the Myelin Protein Zero gene.     

Genetic origin of a large family with a novel PSEN1 mutation (Ile416Thr)

IntroductionA small percentage of Alzheimer's disease (AD) cases are caused by genetic mutations with autosomal dominant inheritance. We report a family with a novel variant in PSEN1.MethodsWe performed clinical and genetic evaluation of 93 related individuals from a Colombian admixed population. 31 individuals had whole-genome sequencing.ResultsGenetic analysis revealed a missense variant in PSEN1 (NM_000021.3: c.1247T>C p.Ile416Thr), which originated on an African haplotype and segregated with AD logarithm of the odds score of 6. Their clinical phenotype is similar to sporadic AD except for earlier age at onset: the mean age at onset for mild cognitive impairment was 47.6 years (standard deviation 5.83) and for dementia 51.6 years (standard deviation 5.03).DiscussionIle416Thr is a novel pathogenic variant that causes AD in the sixth decade of life. The history of the region that included slave importation and admixtures within a confined geographic locale represents a “mini-population bottleneck” and subsequent emergence of a rare dominant mutation.     

Phenotypic variation of a Thr704Met mutation in skeletal sodium channel gene in a family with paralysis periodica paramyotonica

OBJECTIVES: Patients with paralysis periodica paramyotonica exhibit a clinical syndrome with characteristics of both hyperkalaemic periodic paralysis and paramyotonia congenita. In several types of periodic paralysis associated with hyperkalaemia, mutations in the skeletal muscle sodium channel (SCN4A) gene have been previously reported. Phenotypic variations of mutations in SCN4A, however, have not been described yet. The present study aimed to evaluate genetic variations in a family with clinical and electrophysiological characteristics of paralysis periodica paramyotonia. METHODS: Seven members of a family affected with symptoms of paralysis periodica paramyotonia were studied by electrophysiological and genetic analyses. There were increased serum potassium concentrations in four members during paralytic attacks induced by hyperkalaemic periodic paralysis provocation tests. Short exercise tests before and after cold immersion were carried out in four patients to distinguish electrophysiological characteristics of hyperkalaemic periodic paralysis and paramyotonia. Sequencing analyses of SCN4A were performed on one patient and a normal control to identify polymorphisms. Restriction fragment length polymorphism (RFLP) analysis was then performed at the identified polymorphic sites. RESULTS: Electrophysiological studies showed both exercise sensitivity and temperature sensitivity. Compound motor action potential (CMAP) amplitudes were decreased (7.3%-28.6%) after short exercise tests. The CMAP amplitudes were even more severely decreased (21.7%-56.5%) in short exercise tests after cold exposure. Three polymorphic sites, Gln371Glu, Thr704Met, and Aspl376Asn were identified in SCN4A. RFLP analyses showed that all affected patients carried the Thr704Met mutation, whereas unaffected family members and a normal control did not. CONCLUSION: Phenotypic variation of the Thr704Met mutation, which was previously reported in patients with hyperkalaemic periodic paralysis, is described in a family affected with paralysis periodica paramyotonia.     

A novel presenilin 1 mutation (L174 M) in a large Cuban family with early onset Alzheimer disease

We studied a Cuban family with presenile dementia (autosomal dominant) consisting of 281 members within six generations, the proband descended from a Spanish founder. Mean age at onset was 59 years of age. Memory impairment was the main symptom in all patients, additionally, ischemic episodes were described in 4 (n=18) patients. Neuropathological examination of brain material (1 patient) revealed neuronal loss, amyloid plaques, and neurofibrillary tangles. Thirty DNA samples were genotyped (regions on chromosome 1, 3, 10, 12, 14, 17, 19, 20, and 21). A maximum Lod score of 3.79 at θ=0 was obtained for marker D14S43, located in a 9-cM interval in which all patients shared the same haplotype. Sequencing of the PSEN1 gene revealed a heterozygous base substitution, C520A (exon 6), which is predicted to cause an amino acid change from leucine to methionine in the TMIII of the presenilin 1 protein. The mutation was found to co-segregate with the disease phenotype and the associated disease haplotype. The C→A change was not observed in 80 control chromosomes from the Cuban population. Leucine at position 174 is highly conserved among species and is identical in presenilin 1 and presenilin 2 proteins. We propose the L174 M mutation might lead to an abnormal N-terminal and probably C-terminal fragments and malfunction of the protein complex. In conclusion, we found a novel PSEN1 mutation in a large family with clinical and pathological diagnosis of early onset familial Alzheimer disease, which may be relevant for other Hispanic populations. Electronic Publication     

A novel mutation in the CLN1 gene in a patient with juvenile neuronal ceroid lipofuscinosis

We describe the clinical, neuropathological and molecular findings from a patient affected with neuronal ceroid lipofuscinosis with a juvenile onset (JNCL). She was a 9-year-old right-handed girl with a normal birth and early developmental milestones. At the age of 4 the early symptoms began. Skin biopsy showed granular osmiophilic deposits (GRODs). Because JNCL with GRODs is caused by mutations in the CNL1 gene, we performed a molecular investigation by direct sequencing of nine exons of the CNL1 gene. This analysis revealed a novel mutation in homozygous form in the exon 7 that caused an aminoacid substitution at codon 222 (Leu → Pro). Direct sequencing of the exon 7 in both parents showed the same substitution in heterozygous form. Received: 30 November 2001, Received in revised form: 8 April 2002, Accepted: 23 April 2002 RID="*" ID="*"These authors contributed equally to this work RID="*" ID="*"These authors contributed equally to this work Correspondence to Prof. Aldo Quattrone, MD     

A case of familial hemiplegic migraine associated with a novel ATP1A2 gene mutation

Hemiplegic migraine constitutes an unusual form, characterized by periodic attacks of migraine with a motor component (hemiplegia). Familial forms are dominantly inherited, and are attributable to mutations in genes encoding proteins involved in ion transportation, including ATP1A2, which codes for the α-2 isoform of the sodium-potassium adenosine triphosphatase, a P-type cation transport adenosine triphosphatase, and responsible for the so-called familial hemiplegic migraine type 2. We describe a 9-year-old boy affected by familial hemiplegic migraine, with a novel ATP1A2 gene mutation (c.1799T>C p.V600A) in exon 13. Long-term treatment with flunarizine resulted in a good clinical response and the prevention of further attacks.     

A novel ECGF1 mutation in a Thai patient with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive, multisystem disorder, which is clinically defined by ptosis, ophthalmoparesis, gastrointestinal dysmotility, cachexia, peripheral neuropathy, and leukoencephalopathy. MNGIE is caused by mutations in the nuclear gene, endothelial cell growth factor 1 (ECGF1), encoding thymidine phosphorylase (TP). ECGF1 mutations cause severe loss of TP activity, abnormal accumulations of thymidine and deoxyuridine in plasma, and alterations of mitochondrial DNA. Here, we report the first Thai patient with MNGIE confirmed genetically by the identification of a homozygous novel ECGF1 gene mutation, c.100insC, which causes a frameshift and premature truncation of TP protein.     

A novel exon 3 mutation in a Tunisian patient with Lafora's disease

We report a Tunisian patient born from consanguineous marriage affected with progressive myoclonus epilepsy and cognitive decline, consistent with the diagnosis of Lafora disease. Genetic analysis showed a novel c.659 T>A mutation on exon 3 of the EPM2A gene, converting a leucine to a glutamine residue at amino acid position 220 (p.Leu220Gln), in the dual-specificity phosphatase domain.     

A novel PLP mutation in a Japanese patient with mild Pelizaeus-Merzbacher disease

Pelizaeus-Merzbacher disease (PMD) is a rare dysmyelinating disorder due to mutations in the proteolipid protein (PLP) gene. PLP gene mutations are responsible for a broad spectrum of disease, from the most severe form, connatal PMD, to a less severe form, spastic paraplegia 2 (SPG2). We describe here a very mild case of PMD in a patient who presented with nystagmus in early infancy and was unable to walk until 1 year 7 months of age. Brain magnetic resonance imaging (MRI) at 1 year 7 months of age revealed white matter abnormalities typical of PMD. Genetic testing revealed a novel mutation of the PLP gene (Gly197Arg). The patient presented with only mildly ataxic gait and slurred speech at the age of 4 years. Gly197Arg is the first novel mutation located within exon 4 of the PLP gene and associated with mild PMD/SPG2 in a Japanese patient.     

A novel mutation in CSF1R associated with hereditary diffuse leukoencephalopathy with spheroids

Neurological Sciences - Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is a rare autosomal-dominant disorder with high penetrance characterized by progressive cognitive and...     

Novel presenilin 1 mutation associated with early-onset Alzheimer`s disease in a Saudi patient

We report a 60-year-old Saudi patient with the clinical diagnosis of Alzheimer`s disease (AD) and a novel mutation in the presenilin gene. We investigated mutations in the presenilin-1 gene in Saudi patients with AD using polymerase chain reaction and direct DNA sequencing methods. We extracted genomic DNA from the whole blood of both patients and normal control individuals. We sequenced and compared amplicons with the sequences of the respective exons of normal individuals as well as data available in GenBank. We detected a homozygous mutation (g-c) in exon 12, resulting in the missense mutation (Arg377Thr), in the DNA of a 60-year-old patient. We located this mutation in the cytoplasmic loop near the transmembrane domain 7.     

A novel KCNA1 mutation associated with global delay and persistent cerebellar dysfunction

Episodic Ataxia Type 1 is an autosomal dominant disorder characterized by episodes of ataxia and myokymia. It is associated with mutations in the KCNA1 voltage‐gated potassium channel gene. In the present study, we describe a family with novel clinical features including persistent cerebellar dysfunction, cerebellar atrophy, and cognitive delay. All affected family members have myokymia and epilepsy, but only one individual has episodes of vertigo. Additional features include postural abnormalities, episodic stiffness and weakness. A novel KCNA1 mutation (c.1222G>T) which replaces a highly conserved valine with leucine at position 408 (p.Val408Leu) was identified in affected family members, and was found to augment the ability of the channel to inactivate. Together, our data suggests that KCNA1 mutations are associated with a broader clinical phenotype, which may include persistent cerebellar dysfunction and cognitive delay. © 2009 Movement Disorder Society     

Mucolipidosis type IV in a Turkish boy associated with a novel MCOLN1 mutation

Mucolipidosis type IV is a rare neurodegenerative lysosomal storage disorder that usually presents during the first year of life with severe mental retardation, delayed motor milestones and corneal opacities. Mucolipidosis IV is caused by mutations in MCOLN1, a gene encoding mucolipin-1 which is responsible for maintaining lysosomal function. The majority of known patients with this disorders are Ashkenazi Jews, and most have a splice IVS3-2 A>G, or a 6.4 kb deletion mutation in MCOLN1. Here, we present a Turkish patient who, in addition to the typical neurological and visceral characteristics of mucolipidosis type IV, also demonstrates defects in the posterior limb of internal capsule by MRI, micrognathia and clinodactyly of the fifth fingers. Direct sequencing of his DNA revealed a homozygous c.1364C>T (S456L) mutation in MCOLN1, which was heterozygous in both consanguineous parents. This mutation, like several previously described, changes the protein sequence in the channel pore domain of the protein. Serine 456 is conserved in mucolipin proteins throughout evolution, therefore the mutation is considered as causative for the severe phenotype of this patient.