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Summary Purpose Pyridoxine‐dependent epilepsy seizure (PDE; OMIM 266100) is a disorder associated with severe seizures that can be controlled pharmacologically with pyridoxine. In the majority of patients with PDE, the disorder is caused by the deficient activity of the enzyme α‐aminoadipic semialdehyde dehydrogenase (antiquitin protein), which is encoded by the ALDH7A1 gene. The aim of this work was the clinical, biochemical, and genetic analysis of 12 unrelated patients, mostly from Spain, in an attempt to provide further valuable data regarding the wide clinical, biochemical, and genetic spectrum of the disease. Methods The disease was confirmed based on the presence of α‐aminoadipic semialdehyde (α‐AASA) in urine measured by liquid chromatography tandem mass spectrometry (LC‐MS/MS) and pipecolic acid (PA) in plasma and/or cerebrospinal fluid (CSF) measured by high performance liquid chromatography (HPLC)/MS/MS and by sequencing analysis of messenger RNA (mRNA) and genomic DNA of ALDH7A1. Key Findings Most of the patients had seizures in the neonatal period, but they responded to vitamin B6 administration. Three patients developed late‐onset seizures, and most patients showed mild‐to‐moderate postnatal developmental delay. All patients had elevated PA and α‐AASA levels, even those who had undergone pyridoxine treatment for several years. The clinical spectrum of our patients is not limited to seizures but many of them show associated neurologic dysfunctions such as muscle tone alterations, irritability, and psychomotor retardation. The mutational spectrum of the present patients included 12 mutations, five already reported (c.500A>G, c.919C>T, c.1429G>C c.1217_1218delAT, and c.1482‐1G>T) and seven novel sequence changes (c.75C>T, c.319G>T, c.554_555delAA, c.757C>T, c.787 + 1G>T, c.1474T>C, c.1093‐?_1620+?). Only one mutation, p.G477R (c.1429G>C), was recurrent; this was detected in four different alleles. Transcriptional profile analysis of one patient's lymphoblasts and ex vivo splicing analysis showed the silent nucleotide change c.75C>T to be a novel splicing mutation creating a new donor splice site inside exon 1. Antisense therapy of the aberrant mRNA splicing in a lymphoblast cell line harboring mutation c.75C>T was successful. Significance The present results broaden our knowledge of PDE, provide information regarding the genetic background of PDE in Spain, afford data of use when making molecular‐based prenatal diagnosis, and provide a cellular proof‐of concept for antisense therapy application.

AimsHypertrophic cardiomyopathy (HCM) is characterized by a heterogeneous presentation and clinical course. A minority of HCM patients develop end-stage HCM and require cardiac transplantation. The genetic basis of end-stage HCM is unknown but small series, isolated case reports and animal models have related the most aggressive heart failure course with the presence of multiple mutations. Methods and resultsTwenty-six patients (age 40.4 + 14.5 years; 46% male) transplanted for end-stage HCM underwent genetic screening of 10 HCM-related genes (MYH7, MYBPC3, TNNT2, TNNI3, TPM1, TNNC1, MYL3, MYL2, ACTC, LDB3). Additional genetic screening of LAMP2/PRKAG2 and mitochondrial DNA (mtDNA) was performed in four and three cases, respectively. Findings were correlated with clinical and histological features. Pathogenic mutations were identified in 15 patients (58%). Thirteen patients (50%) had mutations in sarcomeric genes (six in MYH7, three in MYBPC3, two in MYL2, one in TNNI3, and one in MYL3) and two patients had mutations in LAMP2. Only three patients (13%) had double mutations and all in homozygosis. Except for a more frequent family history of HCM, patients with mutations in sarcomeric genes did not show any clinical feature that distinguished them from patients without mutations in these genes. Evaluation of 44 relatives from 12 families identified 13 mutation carriers, 9 of whom had an overt HCM phenotype. ConclusionHeart transplanted HCM has a heterogeneous genetic background where multiple mutations are uncommon. The clinical course of HCM is not primarily dependent on the presence of multiple sarcomeric mutations. Clinical and genetic evaluation of relatives does not support differential clinical management in HCM based on genetics.--

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Mitochondrial haplogroups behave like risk factors for the progress to end-stage HF in a Spanish cardiac transplant population. Mitochondrial DNA variants may have some influence on the appearance of cardiac transplant complications.