Joubert syndrome: a model for untangling recessive disorders with extreme genetic heterogeneity.

BACKGROUND: Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterised by hypotonia, ataxia, cognitive impairment, abnormal eye movements, respiratory control disturbances and a distinctive mid-hindbrain malformation. JS demonstrates substantial phenotypic variability and genetic heterogeneity. This study provides a comprehensive view of the current genetic basis, phenotypic range and gene-phenotype associations in JS. METHODS: We sequenced 27 JS-associated genes in 440 affected individuals (375 families) from a cohort of 532 individuals (440 families) with JS, using molecular inversion probe-based targeted capture and next-generation sequencing. Variant pathogenicity was defined using the Combined Annotation Dependent Depletion algorithm with an optimised score cut-off. RESULTS: We identified presumed causal variants in 62% of pedigrees, including the first B9D2 mutations associated with JS. 253 different mutations in 23 genes highlight the extreme genetic heterogeneity of JS. Phenotypic analysis revealed that only 34% of individuals have a 'pure JS' phenotype. Retinal disease is present in 30% of individuals, renal disease in 25%, coloboma in 17%, polydactyly in 15%, liver fibrosis in 14% and encephalocele in 8%. Loss of CEP290 function is associated with retinal dystrophy, while loss of TMEM67 function is associated with liver fibrosis and coloboma, but we observe no clear-cut distinction between JS subtypes. CONCLUSIONS: This work illustrates how combining advanced sequencing techniques with phenotypic data addresses extreme genetic heterogeneity to provide diagnostic and carrier testing, guide medical monitoring for progressive complications, facilitate interpretation of genome-wide sequencing results in individuals with a variety of phenotypes and enable gene-specific treatments in the future.

Variations in cyclic fatigue resistance among ProTaper Gold, ProTaper Next and ProTaper Universal instruments at different levels.

AIM: To compare the cyclic fatigue resistance of ProTaper Gold (PTG, Dentsply Tulsa Dental Specialities, Tulsa, OK, USA), ProTaper Next (PTN, Dentsply Tulsa Dental Specialities) and ProTaper Universal (PTU, Dentsply Tulsa Dental Specialities) instruments at different levels. METHODOLOGY: A total of 72 files were used to evaluate the cyclic fatigue of PTU (F2), PTN (X2) and PTG (F2) at 5 mm (n = 12) and 8 mm (n = 12) from the tip in 3-mm-radius steel canals with a 60° angle of curvature. The time to fracture was recorded. The Kolmogorov-Smirnov test was used to assess the normality of the samples distribution, and the statistical analysis was performed using the independent sample t-test (P < 0.01). RESULTS: Significant differences were found amongst the instruments 5 mm from the tip (P < 0.01). The PTG files had the highest CF resistance, and the PTN files displayed greater CF resistance than the PTU files. No significant differences were found between the PTG and PTN files 8 mm from the tip (P > 0.01). The PTG and PTN files demonstrated greater CF resistance than the PTU files (P < 0.01). CONCLUSIONS: The PTG instruments were the most resistant 5 and 8 mm from the tip; however, at 8 mm, there was no difference between the PTG and PTN instruments. The PTU files had the lowest CF resistance at all levels.

Assessment of root surfaces of apicected teeth: a scanning electron microscopy evaluation.

OBJECTIVES: The aim of this study was to determine the apical surface characteristics and presence of dental cracks in single-rooted premolars, resected 3.0 mm from the root apex, using the Er: YAG laser, tungsten carbide bur, and diamond-coated tip, by scanning electron microscopy (SEM). EXPERIMENTAL DESIGN: Thirty single-rooted premolar teeth were collected. The instrumented and obturated teeth were divided into three groups according to the root resection method (2.94 µm, 100 mj, 20-Hz Er: YAG laser, plain tapered fissure tungsten carbide bur at a low speed of 40,000 rpm, or a diamond-coated SG6D tip coupled to the handpiece of a conventional ultrasound device). The specimens were prepared for SEM and analyzed by the Kruskal-Wallis and Mann-Whitney statistical tests. RESULTS: The SEM images showed that tungsten carbide burs produced significantly smoother resected root surfaces than the diamond-coated tip. There was no statistically significant difference between the Er: YAG and tungsten carbide bur groups. The analysis of scores obtained for the cut quality by the Kruskal-Wallis test revealed no significant differences among the groups. In our study, five teeth had no cracks after the apical resection. The mean number of cracks per tooth was 3.5 ± 1.780 (Er: YAG laser group), 2.5 ± 1.716 (tungsten carbide bur group), and 4.5 ± 2.593 (diamond-coated tip group). CONCLUSIONS: Under the tested conditions smoother surfaces were observed in the groups treated with the tungsten carbide bur and Er: YAG laser when compared with the diamond-coated tips.

Pro-oxidant and antiproliferative effects of the 1,3,4-thiadiazole-based Schiff base and its metal complexes.

Adverse biological activities of Schiff base (SB) derivatives are well known. In this study, the ligand and its metal complexes have been synthesized and characterized by IR, (1)H-NMR spectra, elemental analyses, magnetic susceptibility, UV-Vis spectra, and thermogravimetry/differential thermal analysis. From the elemental analyses data, the complexes were proposed to have the general formula [Mn(L)(2)(H(2)O)(2)], [Co(L)(2)(H(2)O)(2)], and [Ni(2)(L)(H(2)O)(4)(Cl)(3)]. From the magnetic moment and UV-Vis spectra data, it was found that the geometrical structures of these complexes are octahedral. In the in vivo experiment, adult male rats were injected subcutaneously with a new SB (L) and its [Mn(L)(2)(H(2)O)(2)], [Co(L)(2)(H(2)O)(2)], and [Ni(2)(L)(H(2)O)(4)(Cl)(3)] complexes (25 mg/kg body weight) and were then sacrificed 16 days later. Effects of these compounds on serum antioxidant vitamins (i.e., vitamins A, E, and C) and malondialdehyde (MDA) levels were measured in blood serum, liver, and kidney tissues. In an in vitro experiment, antiproliferative effects of these compounds were assessed on the human breast carcinoma MCF-7 and murine leukemia L1210 cell lines. Serum MDA and vitamins A, E, and C levels did not change by the treatments. However, in the kidney and liver tissues, MDA levels were higher, whereas vitamin levels were lower in treatment groups, compared to the control group. All compounds inhibited cell proliferation of MCF-7 and L1210 cancer cell lines in a dose- and time-dependent manner. In conclusion, SB derivatives tested in the current study induced oxidative stress in vivo and exhibited anti-proliferative effects in an in vitro culture system.

Treatment of copper converter slag with deep eutectic solvent as green chemical.

Industrial copper slag is among the most important wastes to be evaluated in terms of containing valuable metals and the amount of waste approaching 30 million tons per year. Therefore, in this study, it was aimed to propose a feasible route for copper and zinc recovery from copper converter slag (CCS) by using choline chloride (ChCl) based deep eutectic solvent which is applied on this type of slag for the first time. During the leaching experiments with the pure ChCl-2urea mixture, temperature (25-95 °C), leaching duration (2-72 h), and pulp density (1/10-1/40 g/mL) were selected as the parameters to be investigated for Cu and Zn extraction. After the experimental results, the optimized conditions for the ChCl-2urea leaching process, which gave 89.9% Cu and 65.3% Zn extraction was found at 48 h, 95 °C, 1/20 g/mL pulp density with 600 rpm stirring speed. It is noted that the iron dissolution ratio is very low (max. 4.7%) under the selected conditions. At the end of the iron cementation stage, the total recovery efficiency as a pure metallic copper was 63%. The calculated activation energy for the dissolution of the copper and zinc from CCS is 8.86 kJ mol-1 and 14.48 kJ mol-1, respectively.

Peripheral neuropathy in a patient with D-2-hydroxyglutaric aciduria.

D-2-hydroxyglutaric aciduria (D-2-HGA; OMIM 600721) is a rare autosomal recessive neurometabolic disorder with a wide clinical spectrum. The severe phenotype is homogeneous and is characterized by early infantile-onset epileptic encephalopathy with hypotonia, delayed cerebral visual development, cardiomyopathy and facial dysmorphic features. The mild phenotype has a more variable clinical expression with hypotonia and developmental delay. We present peripheral neuropathy as an additional clinical and electrophysiological feature in a 16-year-old boy with a homozygous missense mutation in exon 3 of the D-2-hydroxyglutarate dehydrogenase gene (D2HGDH) at position c.458T>C. This mutation results in replacement of a methionine residue, which was highly conserved during evolution, by threonine (p.Met153Thr).

L-2-hydroxyglutaric aciduria: identification of ten novel mutations in the L2HGDH gene.

L-2-hydroxyglutaric aciduria (L-2-HGA) is a metabolic disease with an autosomal recessive mode of inheritance. It was first reported in 1980. Patients with this disease have mutations in both alleles of the L2HDGH gene. The clinical presentation of individuals with L-2-HGA is somewhat variable, but affected individuals typically suffer from progressive neurodegeneration. Analysis of urinary organic acids reveals an increased signal of 2-hydroxyglutaric acid, mainly as the L-enantiomer. L-2-HGA is known to occur in individuals of various ethnic backgrounds, but up to now mutation analysis has been mainly focused on patients of Turkish and Portuguese origin. This led us to confirm the diagnosis on the DNA level and undertake the corresponding mutation analysis in individuals of diverse ethnicity previously diagnosed with L-2-HGA on the basis of urinary metabolites and clinical/neuroimaging data. In 24 individuals from 17 families with diverse ethnic and geographic origins, 13 different mutations were found, 10 of which have not been reported previously. At least eight of the patients were compound heterozygotes. The identification of two mutations (c.751C > T and c.905C > T in exon 7) in patients with different origins supports the view that they occurred independently in different families. In contrast, the mutation c.788C > T was detected in all six Venezuelan patients originating from the same Caribbean island of Margarita, but not in other patients, thus rendering a founder effect likely. None of the mutations was found in the control population, indicating that they are most probably causative. Mutation analysis may improve the quality of diagnosis and prenatal diagnosis of L-2-HGA.

Life-threatening neurological complications after bone marrow transplantation in children.

Neurological complications may occur in BMT recipients (11-59%), frequently contributing to morbidity or mortality. They are the main causes of death in 10-15%. Life-threatening neurological complications were seen in 11 out of 113 (9.7%) children who underwent BMT from HLA-matched family (n=7) or mismatched donors (n=4) at our institution. Diagnoses of patients with neurological complications were acute myeloblastic leukemia (AML) (five), thalassemia major (two), Fanconi anemia (two), Omenn syndrome (one) and leukodystrophy (one), and the neurological events were seen between days +13 and +85 after transplantation. Minor symptoms including reversible, nonrepetitive seizures were excluded. Cyclosporine A toxicity was diagnosed in six children. The rest of the complications were brain abscess/meningoencephalitis (two), severe hypomagnesemia (one), busulfan toxicity (one), sustained hypertension (three), and intracranial hemorrhage (three). Six patients with neurological complications suffered from >grade II graft-versus-host disease (GvHD), and all were high risk for transplant-related complications. In this study, risk status of the underlying disease, mismatched transplantation, a diagnosis of AML (advanced stage), older age and >grade II GvHD were important adverse factors for the development of severe life-threatening neurological complications.

Intestinal lymphangiectasia in a patient with Zellweger cerebrohepatorenal syndrome.

Zellweger cerebrohepatorenal syndrome (ZWCHRS) is an autosomal-recessive disease, characterized by the absence or profound deficiency of peroxisomes. We report a case of ZWCHRS with intestinal lymphangiectasia, observed as an autopsy finding. This combination is previously unreported.

Leigh syndrome in a 3-year-old boy with unusual brain MR imaging and pathologic findings.

We report unusual MR serial imaging and electron microscopy findings in a 3-year-old boy who had Leigh syndrome with cytochrome-c oxidase (cox) deficiency. The MR imaging findings included periventricular white matter involvement, posteroanterior progression, and extension through the corpus callosum and internal capsule; however, no basal ganglia or brain stem abnormality was found, which was suggestive of leukodystrophy. The most noteworthy findings were the cystic foci with contrast enhancement in the affected white matter.

A case of paroxysmal tonic upgaze of childhood with ataxia.

Paroxysmal tonic upgaze of childhood is a rare, distinctive, childhood syndrome that may be associated with ataxia and sometimes strabismus or amblyopia. Neurological examination as well as metabolic studies, electroencephalogram and neuroradiological investigations are normal in these patients. Although it has been considered as an age-related, dopa-sensitive dystonia, the exact pathogenetic mechanism is still unknown. Aggravation of attacks by fatigue, intercurrent infection or vaccination, and possible corticomesencephalic dysmaturation may underlie this abnormality. We report on a sporadic case of paroxysmal tonic upgaze with ataxia in which there was prompt aggravation of symptoms with sleep without response to levodopa treatment. This case suggests a different underlying pathogenetic mechanism from dopaminergic pathways for this syndrome.

Molybdenum cofactor deficiency: report of three cases presenting as hypoxic-ischemic encephalopathy.

We report three infants with the diagnosis of molybdenum cofactor deficiency. The key findings leading to diagnosis were neonatal seizures unresponsive to treatment, craniofacial dysmorphic features, hyperexcitability, low blood uric acid levels, and neuroimaging findings. The parents were consanguineous in two of these patients. The diagnosis was established by the presence of low blood uric acid levels, positive urine sulfite reaction, quantitative aminoacid analysis, and high-voltage electrophoresis of the urine sample showing a typical increase of S-sulfo-L-cysteine. Skin fibroblast cultures confirmed the diagnosis. Magnetic resonance imaging findings were suggestive of encephalomalacia with cystic changes due to hypoxic-ischemic encephalopathy. We conclude that molybdenum cofactor deficiency must be included in the differential diagnosis of patients presenting with intractable seizures in the newborn period who have computed tomography and magnetic resonance imaging findings reminiscent of those of hypoxic-ischemic encephalopathy, and the urine sulfite dipstick test can be a part of the evaluation of these infants in neonatal intensive care units.

Clinical and magnetic resonance imaging features of L-2-hydroxyglutaric acidemia: report of three cases in comparison with Canavan disease.

We report three cases of L-2-hydroxyglutaric acidemia and three cases of Canavan disease. The L-2-hydroxyglutaric acidemia cases are the first biochemically proven Turkish cases. Magnetic resonance imaging findings in the cases and similarities between the two diseases are emphasized. Both diseases are characterized by predominant subcortical white-matter involvement and dentate nuclei lesions with variable basal ganglia involvement. Canavan disease differs from L-2-hydroxyglutaric acidemia by the presence of typical brainstem involvement.

Sandhoff disease in the Turkish population.

Eighteen cases affected by Sandhoff disease were investigated by an enzymatic study of serum and leukocytes during the period 1988-1996, the clinical expression and enzymatic study were reported and discussed. An indirect minimum disease incidence was calculated in the Turkish population. Hexosaminidase activity in serum and leukocytes was severely deficient when measured by synthetic substrate 4-MU-N-acetylglucosaminide using the thermolabile fractionation procedure. Fractionation of hexosaminidase revealed different levels of isoenzymes A and B. Clinically, organomegaly was not found in 11 out of 18 infantile Sandhoff disease patients, while the remaining seven had mild organomegaly. Organomegaly was not found in patients with relatively high % hexosaminidase B activities. These results suggested that patients with different percent heat-stable enzyme activity may have a different type of mutation which is related to the underlying molecular heterogeneity in the Turkish population where 21% of marriages are found to be consanguineous.

An unusual case of Duchenne muscular dystrophy.

A 10-year-old boy with Duchenne muscular dystrophy (DMD), with quite unusual clinical data, is presented. He was unable to walk until age 6, walked only for 9 months and then became wheel-chair bound. No dystrophin was present on muscle biopsy sections and a large deletion was found in the dystrophin gene. The deletion encompassed the central high frequency deletion region of the gene. Early developmental milestones may be delayed in DMD, but patients usually start to walk around 2-3 years of age. A delay of the extent in this case is very unusual.

Mental retardation with rare fragile site expressed at 2q11.

Several rare autosomal folate sensitive fragile sites were reported in individuals with mental retardation, neurological abnormalities, and multiple congenital malformations. Only three of them: fra(11)(q22.3), fra(X)(q27.3) and fra(X)(q28), are known to be associated with mental retardation and phenotypic abnormalities. A possible association of the other rare fragile sites with idiopathic mental retardation is still being discussed. Here, a girl who has a fragile site at 2q11 with minor congenital anomalies and mental retardation is presented. This case has recalled the question of idiopathic mental retardation that might be the clinical expression of rare FSFS. Fragility was observed at 2q11 with a frequency of 3% in her cells along with a partial endoreduplication at 2 q11-->qter.

Megalencephaly and leukodystrophy with mild clinical course: a report on 12 new cases.

Twelve patients with early infancy onset megalencephaly and leukodystrophy with a mild clinical course are reported. The neuroradiological, clinical, and genetic aspects of this recently recognized familial leukodystrophy syndrome were reviewed. Five were affected siblings, and all patients had consanguineous parents. Macrocephaly, a slowly progressive delay in motor development and mild mental deterioration constitute the clinical triad of the disease, showing characteristic age-related onset. The clinical findings outlined remarkably slight functional deterioration despite severe lesions on magnetic resonance imaging (MRI), especially in the initial period. Characteristically, mental function is preserved for years after onset of the motor deficit. The MRI lesions do not reflect the progress of disease. The disease probably has an autosomal recessive mode of inheritance even though no metabolic defect has been detected to date. In a more severe variant of the mentioned disease, there is more progressive and severe neurological dysfunction, including ataxia and spastic quadriparesis, leading to an inability to walk independently after 10 years of age. In mild variants, however, disease severity varies from macrocephaly with near-normal pyschomotor development to mild motor and/or mental dysfunction. Seizures were observed in both types but response to drugs was good. The 12 patients reported here confirm the specific and distinguishing clinical and radiological features of the previously reported 51 cases with this new syndrome, while adding some information regarding identification of the disease.

Selective involvement of the quadriceps muscle in congenital muscular dystrophies: an ultrasonographic study.

Muscle ultrasound scanning is a non-invasive and painless technique for evaluating muscle disorders in childhood. We have performed ultrasound scans of the quadriceps muscle in 26 children with various forms of congenital muscular dystrophies. There were 8 patients clearly showing selective involvement within the components of the quadriceps. In all cases showing selective involvement, the rectus femoris was spared and the vastus muscles were the affected group. Our findings support the concept of heterogeneity, often encountered in congenital muscular dystrophies.

Cockayne syndrome: review of 25 cases.

Clinical and laboratory findings of 25 patients with classical Cockayne syndrome (CS) are reviewed. A history of consanguinity was present in 21 patients, and 15 patients had at least 1 affected sibling. Apart from the cardinal features of dwarfism, microcephaly, and mental retardation, the most consistent clinical features included photosensitivity (84%), gait disturbances (84%), progeroid appearance (84%), and ocular abnormalities (88%). The most consistent laboratory findings comprised abnormal nerve conduction (slowed conduction in 13 of the 16 cases with an ENMG), and an abnormal brainstem auditory evoked response (BAER) and/or audiometry (abnormal in 13 of the 17 cases in whom either one of them were available). Cerebral atrophy and calcification of the basal ganglia were the next more common laboratory findings. Clinical criteria are useful in most instances in the diagnosis of CS. In patients in whom the clinical features are controversial for a diagnosis of Cockayne syndrome, studies directed to disorders of myelination involving both peripheral and central nervous systems in conjunction with audiometry may aid in the diagnosis.

Neurologic features as initial presentations of childhood malignancies.

Thirty patients were examined initially because of neurologic problems and later were diagnosed as having systemic malignant disorders. Acute leukemia was the most common malignancy (36.6%), followed by neuroblastoma (33.3%), non-Hodgkin lymphoma (13.3%), rhabdomyosarcoma (10%), Ewing tumor (3.3%), and Hodgkin lymphoma (3.3%). Four of the 11 acute leukemia patients had nervous system involvement due to meningeal, orbital, or cerebellar infiltration. The complaints of the remaining patients included back pain, weakness, and difficulty in walking, all of which were caused by anemia or bone pain. Neurologic involvement in systemic malignancies, other than acute leukemia, mainly appeared as spinal cord compression (7 with neuroblastoma, 3 non-Hodgkin lymphoma, 1 rhabdomyosarcoma, 1 Ewing tumor), orbital or cavernous sinus infiltration (3 with acute leukemia, 1 rhabdomyosarcoma), and VIIth cranial nerve involvement (2 with rhabdomyosarcoma). One patient had skull infiltration without any neurologic deficit. Cerebellar signs were caused by the remote effects of cancer. It is concluded that acute leukemia is the first and neuroblastoma is the second most common malignancy among childhood systemic malignancies presenting with neurologic involvement; however, neuroblastoma is the most common cause of spinal cord compression.