Mutations in AIFM1 cause an X-linked childhood cerebellar ataxia partially responsive to riboflavin.

BACKGROUND: AIFM1 encodes a mitochondrial flavoprotein with a dual role (NADH oxidoreductase and regulator of apoptosis), which uses riboflavin as a cofactor. Mutations in the X-linked AIFM1 were reported in relation to two main phenotypes: a severe infantile mitochondrial encephalomyopathy and an early-onset axonal sensorimotor neuropathy with hearing loss. In this paper we report two unrelated males harboring AIFM1 mutations (one of which is novel) who display distinct phenotypes including progressive ataxia which partially improved with riboflavin treatment. METHODS: For both patients trio whole exome sequencing was performed. Validation and segregation were performed with Sanger sequencing. Following the diagnosis, patients were treated with up to 200 mg riboflavin/day for 12 months. Ataxia was assessed by the ICARS scale at baseline, and 6 and 12 months following treatment. RESULTS: Patient 1 presented at the age of 5 years with auditory neuropathy, followed by progressive ataxia, vermian atrophy and axonal neuropathy. Patient 2 presented at the age of 4.5 years with severe limb and palatal myoclonus, followed by ataxia, cerebellar atrophy, ophthalmoplegia, sensorineural hearing loss, hyporeflexia and cardiomyopathy. Two deleterious missense mutations were found in the AIFM1 gene: p. Met340Thr mutation located in the FAD dependent oxidoreductase domain and the novel p. Thr141Ile mutation located in a highly conserved DNA binding motif. Ataxia score, decreased by 39% in patient 1 and 20% in patient 2 following 12 months of treatment. CONCLUSION: AIFM1 mutations cause childhood cerebellar ataxia, which may be partially treatable in some patients with high dose riboflavin.

Very Early In-Utero Diagnosis of Walker-Warburg Phenotype: The Cutting Edge of Technology.

BACKGROUND: Walker-Warburg phenotype is a severe and lethal autosomal recessive disorder, belonging to a group of congenital malformations defined as abnormal pial basement membrane formation. So far, prenatal diagnosis was considered possible only during late pregnancy. METHODS: First trimester assessment of a pregnancy suspected to be affected by Walker-Warburg phenotype, using a high-resolution transvaginal ultrasound probe (6-12 MHz), T2 MR imaging (1.5T), molecular genetics and histopathology. RESULTS: Very early diagnosis of the Walker-Warburg phenotype at 11 weeks of gestation proved possible by depicting the classic signs of this entity, confirmed by molecular genetics, post-abortion MR imaging and histopathology. CONCLUSION: Advancements in ultrasound equipment and technology, molecular genetics and histopathology have made very early detection of this syndrome possible, thus shedding new light on the natural history of this malformation.

Founder mutation for Huntington disease in Caucasus Jews.

Huntington disease (HD), an autosomal dominant disorder involving HTT, is characterized by chorea, psychiatric illness and cognitive decline. Diagnosis and age of onset depend on the degree of expansion of the trinucleotide CAG repeat within the gene. The prevalence of HD is known for Europeans but has not been studied in the Israeli population. Between 2006 and 2011 we diagnosed in our adult genetics clinic ten HD probands, nine of whom were Caucasus Jews (CJ) (Azerbaijani), and one Ashkenazi Jewish. We performed haplotype analysis to look for evidence of a founder mutation, and found that of the nine CJ, eight shared the same haplotype that was compatible with the A1 haplogroup. We calculated the coalescence age of the mutation to be between 80 and 150 years. Ninety percent of our HD patients are CJ, as are 27% of the HD patients in Israel, although the CJ comprise only 1.4% of the Israeli population. Our findings suggest a higher prevalence of HD among CJ compared to the general Israeli population and are consistent with a recent founder mutation. We recommend a higher degree of suspicion for HD in CJ with subtle clinical findings.

Androgen Receptor CAG Repeat Length in Relation to Phenotype Among Females with Nonclassical 21-Hydroxylase Deficiency.

Nonclassical 21-hydroxylase deficiency (NC21OHD) manifests with various degrees of post natal virilization. The length of CAG repeats of the androgen receptor gene (AR) is inversely correlated to activity of the human androgen receptor (AR) and affects phenotype of several androgen-dependent disorders. The aim of the study was to investigate the associations between CAG repeat length and the phenotype of females with NC21OHD. CAG repeat length and AR inactivation were assessed in females with NC21OHD, and related to their clinical presentation. CAG repeat length and AR inactivation were assessed in 119 females with NC21OHD. Biallelic mean (BAM) of the CAG repeat length and the weighted BAM (WBAM) were related to various clinical parameters. Age at diagnosis and age of menarche positively correlated with BAM (r=0.22, p=0.02, and r=0.23, p=0.01, respectively). A shorter (<25) BAM was associated with younger age at diagnosis (14.8 vs. 21.4 years, p<0.01), at adrenarche (8.1 vs. 10.2 years, p<0.01) and gonadarche (9.9 vs. 11.2 years, p<0.01), and higher corrected height standard deviation score at diagnosis (0.77 vs. 0.15, p=0.01). Precocious pubarche and precocious puberty were more frequent in these with the shorter BAM. Results of WBAM were similar. The CAG repeat length of the AR gene contributes to the clinical diversity of the phenotype in females with NC21OHD.

Rapidly progressive Creutzfeldt-Jakob disease in patients with Familial Mediterranean Fever.

BACKGROUND: The largest cluster of familial Creutzfeldt-Jakob disease (fCJD) exists in Jews of Libyan origin. Familial Mediterranean fever (FMF) is an inflammatory disease also common in this population. OBJECTIVES: We hypothesized that FMF, as a pro-inflammatory condition, may affect the course of CJD. METHODS: Three hundred and seventy-two consecutive patients diagnosed clinically and genetically as CJD were included in the study. Two hundred and thirty-six had fCJD, and 136 had sporadic disease (sCJD). Review of the patient's records revealed three patients with FMF-CJD co-morbidity. In addition, 50 DNA samples of patients with CJD were genotyped as homozygote, heterozygote, and non-carriers of the FMF mutation. The demographic and clinical variables of the groups were compared. RESULTS: The three patients with FMF had an earlier age of onset and significantly shorter disease duration than the patients without FMF. Heterozygote carriers did not differ in disease onset and duration from patients without FMF. CONCLUSIONS: The shorter disease duration of CJD patients with FMF may indicate the importance of pro-inflammatory factors in the disease.

Germline mutational analysis of presenilin 1 and APP genes in Jewish-Israeli individuals with familial or early-onset Alzheimer disease using denaturing gradient gel electrophoresis (DGGE).

Germ line mutations in three genes have been detected in patients with familial Alzheimer's disease (FAD) and sporadic, early onset disease: amyloid precursor protein (APP), presenilin 1 (PS-1), and presenilin 2 (PS-2). The relative proportions in which mutations in these genes occur among AD patients in Israel has not been evaluated. To that end, we screened 52 Jewish-Israeli patients with AD: 22 with sporadic, early-onset disease (below 65 years), and 30 with FAD. Mutation screen employed denaturing gradient gel electrophoresis (DGGE) of exon-specific PCRs and restriction enzyme digest. Five patients from three different families displayed mutations within the PS-1 gene: three patients of one family showed a mis-sense mutation in codon 120 (Glu 120Lys), and two other unrelated patients showed an identical mis-sense mutation in codon 318 (Glu318Gly). No patient showed an abnormal migration on DGGE (for APP) or mutant restriction digest pattern (for PS-2) genes. These data may indicate the existence of another familial Alzheimer disease (FAD) gene locus in the Israeli Jewish population.

Somatic mutation analysis of the APP and Presenilin 1 and 2 genes in Alzheimer's disease brains.

The molecular basis for sporadic Alzheimer disease (AD) remains largely unknown. We hypothesized that in some cases of sporadic AD, a somatic mutation in an embryonic cell committed to neuronal development within the amyloid precursor protein (APP), the presenilin 1 (PS-1) or the presenilin 2 (PS-2) genes (genes known to be involved in familial AD) may result in AD phenotype. Using PCR, denaturing gradient gel electrophoresis (DGGE), restriction enzyme digest and direct DNA sequencing, we analyzed these genes in 99 brain tissues from patients with histopathologically proven AD. One brain sample showed a mutation within the PS-1 gene, His163 Arg, later shown to be a germline mutation. No other migration abnormalities were demonstrated in any sample in exon 16 or 17 of the APP gene or the coding exons of the PS-1 gene. Restriction digest pattern was normal with regard to the predominant PS-2 gene mutation (N141I). A known mutation in the APP gene, as well as novel mutations within the PS-1 gene were easily detected by DGGE (Reznick Wolf et al. manuscript submitted). We conclude that the genes that are involved in familial AD do not display somatic mutations in the brains of sporadic AD patients, and that other molecular mechanisms are probably involved in the pathogenesis of sporadic AD.

A novel mutation of presenilin 1 in familial Alzheimer's disease in Israel detected by denaturing gradient gel electrophoresis.

Germline mutations in the presenilin 1 (PS1) gene apparently account for the majority of early-onset, familial Alzheimer's disease (AD). Using a mutation-screening strategy (denaturing gradient gel electrophoresis; DGGE), we analyzed a large family with early onset AD and seizures. The patients in this family showed a novel missense mutation in exon 5 of the PS1 gene (A to T change in codon 120, altering glutamine to aspartic acid). This novel mutation is located within the second hydrophilic domain of the molecule, a region not particularly involved in previously described germline mutations, and is of unknown biological significance. These results also demonstrate that DGGE can be used effectively to screen for mutations within this gene.