Novel familial mutation of LRP5 causing high bone mass: Genetic analysis, clinical presentation, and characterization of bone matrix mineralization.

The Wnt signalling pathway is a critical regulator of bone mass and quality. Several heterozygous mutations in the LRP5 gene, a Wnt co-receptor, causing high bone mass (LRP5-HBM) have been described to date. The pathogenic mechanism is thought to be a gain-of-function caused by impaired inhibition of the canonical Wnt signalling pathway, thereby leading to increased bone formation. We report the cases of two affected family members, a 53-year-old mother and her 23-year-old daughter, with high bone mass (T-scores mother: lumbar spine 11.4, femoral neck 10.5; T-scores daughter: lumbar spine 5.4, femoral neck 8.7), increased calvarial thickness, and thickened cortices of the long bones but no history of fractures. Whereas the mother did not show any indications of the mutation, the daughter suffered from congenital hearing impairment resulting in cochlear implantation, recurrent facial palsy, and migraine. In addition, she had stenosis of the foramen magnum. In both individuals, we detected a novel heterozygous duplication of six basepairs in the LRP5 gene, resulting in an insertion of two amino acids, very likely associated with a gain-of-function. When the daughter had part of the occipital bone surgically removed, the bone sample was used for the visualization of bone lamellar structure and bone cells as well as the measurement of bone mineralization density distribution (BMDD). The bone sample revealed two distinctly different regions: an intra-cortical region with osteonal remodeling, typical osteonal lamellar orientation, associated with relatively higher heterogeneity of bone matrix mineralization, and another periosteal region devoid of bone remodeling, with parallel bone lamellae and lower heterogeneity of mineralization. In conclusion, we present data on bone tissue and material level from an LRP5-HBM patient with a novel mutation in the LRP5 gene. Our findings indicate normal morphology of osteoclasts and osteoblasts as well as normal mineralization in skull bone in LRP5-HBM.

Increased frequency of MEFV gene mutations in patients with primary dysmenorrhea.

OBJECTIVES: Familial Mediterranean fever (FMF) is an autoinflammatory disease characterized by recurrent attacks of fever and polyserositis and an autosomal recessive inheritance mode. Up to 15 % of FMF patients are reported to experience perimenstrual attacks. Primary dysmenorrhea could be an incomplete abdominal attack, or patients with dysmenorrhea may have increased frequency of MEFV gene mutation carriage. Therefore, we aimed to evaluate the frequency of MEFV gene mutations in patients with dysmenorrhea. METHODS: Eighty-four patients with primary dysmenorrhea attending consecutively to our gynecology department and 73 healthy female controls selected from hospital staff were included in the study, and MEFV gene mutations were analyzed. RESULTS: The prevalence of total allelic variants was significantly increased in dysmenorrhea patients (p = 0.015); analysis of individual variant rates revealed a significant increase in the frequency of MEFV gene mutations in dysmenorrhea patients compared with the control group (p = 0.036). CONCLUSION: Gynecologists and primary care physicians must be aware of FMF in the differential diagnosis of dysmenorrhea.

Selective bilateral hippocampal lesions after theophylline-induced status epilepticus causes a permanent amnesic syndrome.

Theophylline is known to increase the risk of epileptic seizures and might have a role in seizure-induced brain damage. We present a 55-year-old man who developed an amnesic syndrome after status epilepticus, caused by accidental theophylline intoxication. Imaging studies revealed acute, selective bilateral hippocampal damage, which corresponded to severe disturbances in bilateral temporal functions on neuropsychological testing. Three months later, the memory deficits persisted, while imaging exhibited bilateral atrophy of the hippocampus. Upon his long-term, 18-month follow-up, the patient demonstrated improvements in his daily living abilities, despite the persistence of bilateral temporal deficits. This report provides evidence that theophylline has the potential to provoke permanent seizure-induced neural damage, presumably via inhibition of adenosine receptors, and especially in vulnerable regions of the brain, such as the hippocampus.

Correlation of enzyme activity and clinical phenotype in POMT1-associated dystroglycanopathies.

BACKGROUND: Mutations in protein O-mannosyltransferases (POMTs) cause a heterogeneous group of muscular dystrophies with abnormal glycosylation of alpha-dystroglycan (dystroglycanopathies). The wide spectrum of clinical severities ranges from Walker-Warburg syndrome (WWS), associated with brain and eye abnormalities, to mild forms of limb girdle muscular dystrophy (LGMD). OBJECTIVE: The aim of this study was to elucidate the impact of mutations in POMT1 on the clinical phenotype. METHODS: We examined 2 patients with POMT1-associated alpha-dystroglycanopathy, 1 displaying a LGMD2K and 1 with a WWS phenotype. Using dermal fibroblasts, we analyzed the influence of the POMT1 mutations on the glycosylation status of alpha-dystroglycan, protein O-mannosyltransferase activity, and the stability of the mutant POMT1 protein. RESULTS: We report on novel compound heterozygous mutations in POMT1 (p.L171A and p.A589VfsX38) that result in LGMD2K. We further demonstrate that a homozygous splice site mutation of a recently identified WWS patient results in POMT1 p.del77-93. Using dermal fibroblasts, we show that mannosyltransferase activity is reduced in the patients and that stability of POMT1 mutant proteins p.A589VfsX38 and p.del77-93 is significantly decreased. CONCLUSIONS: Our results suggest that dermal fibroblasts can be applied to facilitate the diagnostic analysis of dystroglycanopathy patients as well as to study the pathogenic mechanism of POMT mutations. Characterization of the POMT1 substrate protein alpha-dystroglycan and POMT in vitro mannosyltransferase activity shows that the severity of the clinical phenotype of the patients analyzed is inversely correlated with POMT activity.

Refining the phenotype of alpha-1a Tubulin (TUBA1A) mutation in patients with classical lissencephaly.

Mutations in the alpha-1a Tubulin (TUBA1A) gene have recently been found to cause cortical malformations resemblant of classical lissencephaly but with a specific combination of features. To date, TUBA1A mutations have been described in five patients and three foetuses. Our aims were to establish how common TUBA1A mutations are in patients with lissencephaly and to contribute to defining the phenotype associated with TUBA1A mutation. We performed mutation analysis in the TUBA1A gene in 46 patients with classical lissencephaly. In 44 of the patients, mutations in the LIS1 and/or DCX genes had previously been excluded; in 2 patients, mutation analysis was only performed in TUBA1A based on magnetic resonance imaging (MRI) findings. We identified three new mutations and one recurrent mutation in five patients with variable patterns of lissencephaly on brain MRI. Four of the five patients had congenital microcephaly, and all had dysgenesis of the corpus callosum and cerebellar hypoplasia, and variable cortical malformations, including subtle subcortical band heterotopia and absence or hypoplasia of the anterior limb of the internal capsule. We estimate the frequency of mutation in TUBA1A gene in patients with classical lissencephaly to be approximately 4%, and although not as common as mutations in the LIS1 or DCX genes, mutation analysis in TUBA1A should be included in the molecular genetic diagnosis of classical lissencephaly, particularly in patients with the combination of features highlighted in this paper.

Location and type of mutation in the LIS1 gene do not predict phenotypic severity.

BACKGROUND: Lissencephaly is a neuronal migration disorder leading to absent or reduced gyration and a broadened but poorly organized cortex. The most common form of lissencephaly is isolated, referred as classic or type 1 lissencephaly. Type 1 lissencephaly is mostly associated with a heterozygous deletion of the entire LIS1 gene, whereas intragenic heterozygous LIS1 mutations or hemizygous DCX mutations in males are less common. METHODS: Eighteen unrelated patients with type 1 lissencephaly were clinically and genetically assessed. In addition, patients with subcortical band heterotopia (n = 1) or lissencephaly with cerebellar hypoplasia (n = 2) were included. RESULTS: Fourteen new and seven previously described LIS1 mutations were identified. We observed nine truncating mutations (nonsense, n = 2; frameshift, n = 7), six splice site mutations, five missense mutations, and one in-frame deletion. Somatic mosaicism was assumed in three patients with partial subcortical band heterotopia in the occipital-parietal lobes or mild pachygyria. We report three mutations in exon 11, including a frameshift which extends the LIS1 protein, leading to type 1 lissencephaly and illustrating the functional importance of the WD domains at the C terminus. Furthermore, we present two patients with novel LIS1 mutations in exon 10 associated with lissencephaly with cerebellar hypoplasia type a. CONCLUSION: In contrast to previous reports, our data suggest that neither type nor position of intragenic mutations in the LIS1 gene allows an unambiguous prediction of the phenotypic severity. Furthermore, patients presenting with mild cerebral malformations such as subcortical band heterotopia or cerebellar hypoplasia should be considered for genetic analysis of the LIS1 gene.

Further clinical and genetic characterization of SPG11: hereditary spastic paraplegia with thin corpus callosum.

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders leading to progressive spasticity of the lower limbs. Clinically, HSPs are divided into "pure" and "complicated" forms. In pure HSP, the spasticity of the lower limbs is the sole symptom, whereas in complicated forms additional neurological and non-neurological features are observed. Genetically, HSPs are divided into autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) forms. Up to date, 30 different HSPs are linked to different chromosomal loci and 11 genes could be defined for AR-HSP, AD-HSP and XL-HSP. SPG11, an AR-HSP (synonym: HSP11), is a complicated HSP associated with a slowly progressive spastic paraparesis, mental impairment and the development of a thin corpus callosum (TCC) during the course of the disease. SPG11 has been previously linked to chromosomal region 15q13 - 15. First, we applied rigid diagnostic criteria to systematically examine 20 Turkish families with autosomal recessive HSP for characteristic features of SPG11. We detected four large Turkish families with AR-HSP and TCC consistent with SPG11. Subsequent genetic linkage analysis of those 4 families refines the SPG11 locus further down to a small region of 2.93 cM with a maximum lod score of 11.84 at marker D15S659 and will guide further candidate gene analysis.

Relation between laterality and immune response after acute cerebral ischemia.

OBJECTIVE: During the last 2 decades, right/left hemisphere dominance was supposed to affect the immune system differently. Experimental and clinical observations indicate that the left hemisphere plays a crucial role in the development of the immune system. The true relationship between immune response and acute ischemic stroke laterality remains to be elucidated. METHODS: We studied acute right-handed stroke patients admitted to a single acute neurology department with a specialized stroke unit. Being part of our clinical protocol, blood samples were taken within the first 24 h after the onset of stroke symptoms. The medical record of each patient was reviewed, and demographic, clinical laboratory (key criteria: C-reactive protein, CRP, and white blood cell count, WBC) and neuroimaging information was retrieved. All data were presented descriptively, and bivariate test statistics, ANOVA (log-transformed data) or linear correlations were calculated. RESULTS: Fifty-six of the 187 patients admitted to our Stroke Unit between October 2003 and March 2004 with different stroke subtypes according to the TOAST criteria were retrospectively evaluated in order to characterize the impact of stroke laterality on immunoregulatory response measured by CRP levels and WBC. Correlation analysis revealed that left-sided ischemic stroke yielded a significantly higher correlation between CRP levels and WBC. Following left-sided stroke, a more marked variability in CRP and WBC was found compared to patients with right-sided ischemic stroke, although ANOVA did not show significant differences between immune response values as a function of stroke subtypes. CONCLUSIONS: We identified an association between stroke laterality and immunoregulatory response in patients with acute ischemic stroke. Left-sided stroke may be considered as a direct risk factor for infectious disease or immune deficits and should attract special attention. However, these preliminary results need be confirmed by controlled studies.

Novel truncating and missense mutations of the KCC3 gene associated with Andermann syndrome.

BACKGROUND: Andermann syndrome (OMIM 218000) is an autosomal recessive motor-sensory neuropathy associated with developmental and neurodegenerative defects. The cerebral MRI reveals a variable degree of agenesis of the corpus callosum. Recently, truncating mutations of the KCC3 gene (also known as SLC12A6) have been associated with Andermann syndrome. METHODS: The authors assessed clinically and genetically three isolated cases from Germany and Turkey with symptoms consistent with Andermann syndrome. RESULTS: The authors detected four novel mutations within the KCC3 gene in their patients: two different truncating mutations in the first patient, a homozygous truncating mutation in the second, and a homozygous missense mutation in the third patient. In contrast to the classic phenotype of the Andermann syndrome linked to truncating KCC3 mutations the phenotype and the course of the disease linked to the missense mutation appeared to be different (i.e., showing additional features like diffuse and widespread white matter abnormalities). CONCLUSIONS: Not only truncating but also missense mutations of the KCC3 gene are associated with Andermann syndrome. Different types of KCC3 mutations may determine different clinical phenotypes.

A filamin A splice mutation resulting in a syndrome of facial dysmorphism, periventricular nodular heterotopia, and severe constipation reminiscent of cerebro-fronto-facial syndrome.

BACKGROUND: Mutations of the filamin A locus (FLNA) on Xq28 have been established in girls with periventricular nodular heterotopia and in patients with otopalatodigital and overlapping phenotypes, the pathogenesis of these phenotypes being thought to be quite distinct. To date only six male cases of periventricular nodular heterotopia (PVNH) have been reported and these almost invariably associated with severe neurological signs. METHODS AND RESULTS: We report a new phenotype of male PVNH, with relatively normal development, no epilepsy or other neurological abnormality, severe constipation, and facial dysmorphism and without a discernible skeletal phenotype. This phenotype is associated with a splice site mutation in FLNA c.1923C>T, resulting in the generation of both normal and aberrant mRNA. CONCLUSIONS: We postulate that the patient retains enough FLNA function to avoid the usual lethality associated with loss of function mutations in males and suggest that the severe constipation may be a clue to the molecular aetiology of other X linked conditions associated with severe constipation.

[Congenital muscular dystrophies: muscle-eye-brain disease]. / Kongenitale Muskeldystrophie: Muscle-Eye-Brain disease.

Three rare autosomal recessive disorders share the combination of congenital muscular dystrophy and brain malformations including a neuronal migration defect: muscle-eye-brain disease (MEB), Walker-Warburg syndrome (WWS), and Fukuyama congenital muscular dystrophy (FCMD). In addition, ocular abnormalities are a constant feature in MEB and WWS. We report on two brothers with MEB. The clinical and radiological characteristics are demonstrated.

Agenesis of the corpus callosum, abnormal genitalia and intractable epilepsy due to a novel familial mutation in the Aristaless-related homeobox gene.

Mutations in the Aristaless-related homeobox (ARX) gene are associated with a broad spectrum of disorders including X-linked lissencephaly with abnormal genitalia (XLAG) and absent corpus callosum. Here, we describe a family with two male infants suffering from agenesis of the corpus callosum (ACC), intractable epilepsy, and abnormal genitalia. The phenotype of both affected patients differed in severity of the cerebral malformation with one showing no obvious evidence for lissencephaly. Both infants lacked any psychomotor development and died at the age of 17 weeks and 18 months, respectively. Genetic analysis of the ARX gene revealed a novel frameshift mutation in exon 4 (nt1419_1420insAC) leading to a shortened protein lacking the aristaless domain. In summary, analysis of the ARX gene should not only be considered in male patients with typical features of XLAG but also in those presenting with early onset epilepsy, ACC, and abnormal genitalia without obvious neuroradiological features of lissencephaly.

X-linked lissencephaly with abnormal genitalia associated with renal phosphate wasting.

X-linked lissencephaly with abnormal genitalia (XLAG) is a rare disorder caused by mutations in the aristaless-related homeobox (ARX) gene. We report on the clinical data of a boy with a 1-bp deletion (790 delC) resulting in a frame shift in the ARX gene and prolonged survival until age 18 months. Similar to other patients, the boy showed postnatal microcephaly, hypothalamic dysfunction, intractable neonatal seizures, and chronic diarrhoea. In addition, he suffered from exocrine pancreatic insufficiency and renal phosphate wasting became apparent from age 5 months, both of which have not been described previously in XLAG. This allows us to speculate that the phenotype of XLAG is more complex than hitherto known and may include renal phosphate wasting which might not have been observed in other patients due to early death.

Clinical spectrum of muscle-eye-brain disease: from the typical presentation to severe autistic features.

Muscle-eye-brain disease (MEB) is an autosomal recessive congenital muscular dystrophy with ocular abnormalities and type II lissencephaly. MEB is caused by mutations in the protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase (POMGnT1) gene on chromosome 1q33. POMGnT1 is a glycosylation enzyme that participates in the synthesis of O-mannosyl glycan. The disease is characterized by altered glycosylation of alpha-dystroglycan. The clinical spectrum of MEB phenotype and POMGnT1 mutations are significantly expanded. We would like to present two cases with MEB disease with POMGnT1 mutations, whose clinical picture shows heterogeneity. The patient with R442H mutation had the classical form of the disease although the one with IVS17-2A-->G homozygous mutation had severe autistic features as the dominating presenting sign. These two cases represent different spectrums of one disorder. To the best of our knowledge, autistic features and stereotypical movements have not been included thus far as a part of broad and heterogeneous MEB spectrum.

ARX mutations in X-linked lissencephaly with abnormal genitalia.

X-linked lissencephaly with abnormal genitalia (XLAG) is a distinct form of lissencephaly associated with absent corpus callosum. Recently, forms of syndromic and nonspecific X-linked mental retardation have been found to be associated with mutations in the Aristaless-related homeobox gene ARX. The authors assessed ARX as a candidate gene for XLAG in a genetic analysis of neuronal migration disorders and found two different point mutations in two XLAG pedigrees affecting the homeodomain of the protein, confirming that ARX is a causative gene for XLAG.

Somatic mosaicism and variable penetrance in doublecortin-associated migration disorders.

X-linked isolated lissencephaly sequence (XLIS) and subcortical band heterotopia (SBH) are allelic disorders caused by mutations in the doublecortin (DCX) gene. This genetic analysis of seven families revealed four novel mutations in the DCX gene. The authors detected a high rate of somatic mosaicism in male and female patients with variable penetrance of bilateral SBH including nonpenetrance in a heterozygous woman. In addition, the authors implemented prenatal diagnosis in a family with SBH/XLIS.

Molecular mechanisms of neuronal migration disorders, quo vadis?

Following terminal mitosis, neuronal precursor cells leave their site of origin and migrate towards their definitive site of residency. In order to establish the intricate cytoarchitecture described in the adult human brain, neuronal migration must be finely regulated. In humans, brain malformations can result from neuronal migration defects. The spectrum of migration disorder severity extends from few heterotopic neurons, as observed in periventricular heterotopia, to a complete cortical disorganization, as observed in cases of lissencephaly. Recently, specific migration disorders have been linked to mutations/deletions in the doublecortin, filamin-1, LIS1 and reelin genes. These proteins act at different levels of the signaling cascades transducing extracellular guiding cues into cytoskeletal reorganization. Here, we summarize the data concerning these four molecules and speculate on their functions and interaction partners during neuronal development.

Increased nuchal translucency in a case of long-chain 3-hydroxyacyl- coenzyme A dehydrogenase deficiency.

We present a case where the embryo showed an increased nuchal edema and a metabolic disorder. At 31 weeks of gestation the fetus developed a cardiomegaly and a hydrops. In this case, a long-chain 3-hydroxacyl-coenzyme A dehydrogenase deficiency (LCHAD deficiency) was confirmed by biochemical investigations in cultured chorionic villus cells and by DNA analysis. This metabolic disease causes a reduced production of mitochondrial trifunctional proteins and is a very rare autosomal-recessive disease.