COL4A1-related autosomal recessive encephalopathy in 2 Turkish children.

OBJECTIVE: This study presents the neurologic phenotypes of 2 brothers with a novel homozygous COL4A1 mutation that was identified in a large Turkish consanguineous cohort of neurogenetic diseases. METHODS: Whole-exome sequencing and bioinformatic analysis of consanguineous families with children affected by early-onset, neurogenetic disorders was performed using the RD-Connect Genome-Phenome Analysis Platform. We also performed clinical, EEG, and neuroimaging analyses in unaffected siblings and parents. RESULTS: We have identified a homozygous missense mutation in COL4A1 (p.Gly1278Ser, NM_001845.5:c.3832G>T) in 2 siblings affected by small vessel brain disease with periventricular leukoencephalopathy and ocular defects. Presenting symptoms included mild weakness, hemiparetic gait, pyramidal findings, and seizures, whereas their intellectual and behavioral functions were normal. Both parents and 5 of the siblings (3 boys and 2 girls) were heterozygous for the variant. They did not show any clinical or laboratory signs of small vessel disease. CONCLUSIONS: COL4A1 has previously been associated with dominant small vessel disease of the brain and other organs, manifesting with high penetrance in heterozygous mutation carriers. Our findings provide evidence that COL4A1-related encephalopathy can be inherited in an autosomal recessive manner, which is important for counseling, prognosis, and treatment. Genotype-phenotype correlations remain to be established

Autosomal recessive variants in TUBGCP2 alter the γ-tubulin ring complex leading to neurodevelopmental disease.

Microtubules help building the cytoskeleton of neurons and other cells. Several components of the gamma-tubulin (γ-tubulin) complex have been previously reported in human neurodevelopmental diseases. We describe two siblings from a consanguineous Turkish family with dysmorphic features, developmental delay, brain malformation, and epilepsy carrying a homozygous mutation (p.Glu311Lys) in TUBGCP2 encoding the γ-tubulin complex 2 (GCP2) protein. This variant is predicted to disrupt the electrostatic interaction of GCP2 with GCP3. In primary fibroblasts carrying the variant, we observed a faint delocalization of γ-tubulin during the cell cycle but normal GCP2 protein levels. Through mass spectrometry, we observed dysregulation of multiple proteins involved in the assembly and organization of the cytoskeleton and the extracellular matrix, controlling cellular adhesion and of proteins crucial for neuronal homeostasis including axon guidance. In summary, our functional and proteomic studies link TUBGCP2 and the γ-tubulin complex to the development of the central nervous system in humans

Severe neurodevelopmental disease caused by a homozygous TLK2 variant

Abstract: A distinct neurodevelopmental phenotype characterised mainly by mild motor and language delay and facial dysmorphism, caused by heterozygous de novo or dominant variants in the TLK2 gene has recently been described. All cases reported carried either truncating variants located throughout the gene, or missense changes principally located at the C-terminal end of the protein mostly resulting in haploinsufficiency of TLK2. Through whole exome sequencing, we identified a homozygous missense variant in TLK2 in a patient showing more severe symptoms than those previously described, including cerebellar vermis hypoplasia and West syndrome. Both parents are heterozygous for the variant and clinically unaffected highlighting that recessive variants in TLK2 can also be disease causing and may act through a different pathomechanism

Infantile iatrogenic cushing′s syndrome

High potency or/and extended use of topical corticosteroids, particularly in children, may cause suppression of the hypothalamopituitary-adrenal axis. However, iatrogenic Cushing′s syndrome in infantile age group is very rare and only a few patients have been reported to date in the literature. Here, we report a case of iatrogenic Cushing′s syndrome in a 6-month-old male child whose parents have admitted to the hospital for overweight and skin fragility

Clinical features of nine patients with alternating hemiplegia of childhood

Aim: To define clinical features of patients with alternating hemiplegia of childhood

Severe neurodevelopmental disease caused by a homozygous TLK2 variant

Abstract: A distinct neurodevelopmental phenotype characterised mainly by mild motor and language delay and facial dysmorphism, caused by heterozygous de novo or dominant variants in the TLK2 gene has recently been described. All cases reported carried either truncating variants located throughout the gene, or missense changes principally located at the C-terminal end of the protein mostly resulting in haploinsufficiency of TLK2. Through whole exome sequencing, we identified a homozygous missense variant in TLK2 in a patient showing more severe symptoms than those previously described, including cerebellar vermis hypoplasia and West syndrome. Both parents are heterozygous for the variant and clinically unaffected highlighting that recessive variants in TLK2 can also be disease causing and may act through a different pathomechanism

Confirmation of TACO1 as a Leigh Syndrome Disease Gene in Two Additional Families.

BACKGROUND: In 2009, we identified TACO1 as a novel mitochondrial disease gene in a single family, however no second family has been described to confirm the role of TACO1 in mitochondrial disease. OBJECTIVE: In this report, we describe two independent consanguineous families carrying pathogenic variants in TACO1, confirming the phenotype. METHODS: Detailed clinical investigations and whole exome sequencing with haplotype analysis have been performed in several members of the two reported families. RESULTS: Clinical phenotype of the patients confirms the originally reported phenotype of a childhood-onset progressive cerebellar and pyramidal syndrome with optic atrophy and learning difficulties. Brain MRI showed periventricular white matter lesions with multiple cystic defects, suggesting leukoencephalopathy in both patients. One patient carried the previously described homozygous TACO1 variant (p.His158ProfsTer8) and haplotype analysis suggested that this variant is a rare founder mutation. The second patient from another family carried a homozygous novel frame shift variant (p.Cys85PhefsTer15). CONCLUSIONS: The identification of two Turkish families with similar characteristic clinical presentation and an additional homozygous nonsense mutation confirms that TACO1 is a human mitochondrial disease gene. Although most patients with this clinical presentation undergo next generation sequencing analysis, screening for selected founder mutations in the Turkish population based on the precise clinical presentation may reduce time and cost of finding the genetic diagnosis even in the era of massively parallel sequencing.Wellcome Trust, MR

Autosomal recessive variants in TUBGCP2 alter the gamma-tubulin ring complex leading to neurodevelopmental disease

Microtubules help building the cytoskeleton of neurons and other cells. Several components of the gamma-tubulin (gamma-tubulin) complex have been previously reported in human neurodevelopmental diseases. We describe two siblings from a consanguineous Turkish familywith dysmorphic features, developmental delay, brain malformation, and epilepsy carrying a homozygous mutation (p.Glu311Lys) in TUBGCP2 encoding the gamma-tubulin complex 2 (GCP2) protein. This variant is predicted to disrupt the electrostatic interaction of GCP2 with GCP3. In primary fibroblasts carrying the variant, we observed a faint delocalization of gamma-tubulin during the cell cycle but normal GCP2 protein levels. Through mass spectrometry, we observed dysregulation of multiple proteins involved in the assembly and organization of the cytoskeleton and the extracellular matrix, controlling cellular adhesion and of proteins crucial for neuronal homeostasis including axon guidance. In summary, our functional and proteomic studies link TUBGCP2 and the gamma-tubulin complex to the development of the central nervous system in humans

A Multinational Survey on Actual Diagnostics and Treatment of Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a chronic infection of the central nervous system caused by the measles virus (MV). Its prevalence remains high in resource poor countries and is likely to increase in the Northern Europe as vaccination rates decrease. Clinical knowledge of this devastating condition, however, is limited. We therefore conducted this multinational survey summarizing experience obtained from more than 500 patients treated by 24 physicians in seven countries. SSPE should be considered in all patients presenting with otherwise unexplained acquired neurological symptoms. In most patients, the diagnosis will be established by the combination of typical clinical symptoms (characteristic repetitive myoclonic jerks), a strong intrathecal synthesis of antibodies to MV and typical electroencephalogram findings (Radermecker complexes). Whereas the therapeutic use of different antiviral (amantadine, ribavirin) and immunomodulatory drugs (isoprinosine, interferons) and of immunoglobulins has been reported repeatedly, optimum application regimen of these drugs has not been established. This is partly due to the absence of common diagnostic and clinical standards focusing on neurological and psychosocial aspects. Carbamazepine, levetiracetam, and clobazam are the drugs most frequently used to control myoclonic jerks. We have established a consensus on essential laboratory and clinical parameters that should facilitate collaborative studies. Those are urgently needed to improve outcome