Background: Cortical gray matter reductions and cerebrospinal fluid (CSF) increases are robust correlates of schizophrenia, but their relationships to obstetric and other etiologic risk factors remain to be established.

BackgroundKallmann syndrome (KS), comprised of congenital hypogonadotropic hypogonadism (HH) and anosmia, is a clinically and genetically heterogeneous disorder. Its exact incidence is currently unknown, and a mutation in one of the identified KS genes has only been found in ~30% of the patients.MethodsHerein, we investigated epidemiological, clinical, and genetic features of KS in Finland.ResultsThe minimal incidence estimate of KS in Finland was 1:48 000, with clear difference between males (1:30 000) and females (1:125 000) (p = 0.02). The reproductive phenotype of 30 probands (25 men; 5 women) ranged from severe HH to partial puberty. Comprehensive mutation analysis of all 7 known KS genes (KAL1, FGFR1, FGF8, PROK2, PROKR2, CHD7, and WDR11) in these 30 well-phenotyped probands revealed mutations in KAL1 (3 men) and FGFR1 (all 5 women vs. 4/25 men), but not in other genes.ConclusionsOur results suggest that Finnish KS men harbor mutations in gene(s) yet-to-be discovered with sex-dependent penetrance of the disease phenotype. In addition, some KS patients without CHD7 mutations display CHARGE-syndrome associated phenotypic features (e.g. ear or eye anomalies), possibly implying that, in addition to CHD7, there may be other genes associated with phenotypes ranging from KS to CHARGE.

Background: Cortical gray matter volume reductions and cerebrospinal fluid (CSF) volume increases are robust correlates of schizophrenia, but their sources have not been established conclusively.

Patient and graft survival rates of pediatric renal transplant recipients are currently excellent, but there are few reports regarding the long-term neurodevelopmental outcome after renal transplantation (Tx) in early childhood. Children with renal failure from infancy would be expected to have a less favorable developmental prognosis. We report the neurodevelopmental outcome in 33 school-age children transplanted between 1987 and 1995 when < 5 yr of age. We prospectively performed a neurological examination, magnetic resonance imaging (MRI) of the brain, electroencephalograms (EEGs), audiometry, and neuropsychological tests (NEPSY), and measured cognitive performance (WISC-R); we related these results to school performance and to retrospective risk factors prior to Tx. Twenty-six (79%) children attended normal school and 76% had normal motor performance. Six of the seven children attending a special school had brain infarcts on MRI. The EEG was abnormal in 11 (35%), and five (15%) received anti-convulsive treatment after Tx. Sensorineural hearing loss was documented in six patients. The mean intelligence quotient (IQ) was 87, and 6-24% showed impairment in neuropsychological tests. The children attending a special school had been more premature, but had not had a greater number of pre- or neonatal complications. They had experienced a greater number of hypertensive crises (p = 0.002) and seizures (p = 0.03), mainly during dialysis, but the number of septic infections and the mean serum aluminum levels were not significantly greater than in the children with normal school performance. In these previously lethal diseases, the overall neurodevelopmental outcome is reassuring. However, it is of crucial importance to further minimize the risk factors prior to Tx.

Next-generation sequencing has turned out to be a powerful tool to uncover genetic basis of childhood mitochondrial disorders. We utilized whole-exome analysis and discovered novel compound heterozygous mutations in FARS2 (mitochondrial phenylalanyl transfer RNA synthetase), encoding the mitochondrial phenylalanyl transfer RNA (tRNA) synthetase (mtPheRS) in two patients with fatal epileptic mitochondrial encephalopathy. The mutations affected highly conserved amino acids, p.I329T and p.D391V. Recently, a homozygous FARS2 variant p.Y144C was reported in a Saudi girl with mitochondrial encephalopathy, but the pathogenic role of the variant remained open. Clinical features, including postnatal onset, catastrophic epilepsy, lactic acidemia, early lethality and neuroimaging findings of the patients with FARS2 variants, resembled each other closely, and neuropathology was consistent with Alpers syndrome. Our structural analysis of mtPheRS predicted that p.I329T weakened ATP binding in the aminoacylation domain, and in vitro studies with recombinant mutant protein showed decreased affinity of this variant to ATP. Furthermore, p.D391V and p.Y144C were predicted to disrupt synthetase function by interrupting the rotation of the tRNA anticodon stem-binding domain from a closed to an open form. In vitro characterization indicated reduced affinity of p.D391V mutant protein to phenylalanine, whereas p.Y144C disrupted tRNA binding. The stability of p.I329T and p.D391V mutants in a refolding assay was impaired. Our results imply that the three FARS2 mutations directly impair aminoacylation function and stability of mtPheRS, leading to a decrease in overall tRNA charging capacity. This study establishes a new genetic cause of infantile mitochondrial Alpers encephalopathy and reports a new mitochondrial aminoacyl-tRNA synthetase as a cause of mitochondrial disease.