Diabetes mellitus, diabetes insipidus, and optic atrophy. An autosomal recessive syndrome?

WFS1/wolframin mutations, Wolfram syndrome, and associated diseases

Wolfram syndrome (WS) is the inherited association of juvenile-onset insulin-dependant diabetes mellitus and progressive bilateral optic atrophy. A nuclear gene, WFS1/wolframin, was identified that segregated with disease status and demonstrated an autosomal recessive mode of inheritance. Mutation analysis of the WFS1 gene in WS patients has identified mutations in 90% of patients. Most were compound heterozygotes with private mutations distributed throughout the gene with no obvious hotspots. The private nature of the mutations in WS patients and the low frequencies make it difficult to determine the biological or clinical relevance of these mutations. Mutation screening in patients with psychiatric disorders or diabetes mellitus has also been performed to test the hypothesis that heterozygous carriers of WFS1 gene mutations are at an increased risk following the observation that WS first-degree relatives have a higher frequency of these disorders. Most studies showed no association, however two missense mutations were identified that demonstrated significant association with psychiatric disorders and diabetes mellitus. Population association studies and functional studies of these variants will need to be performed to confirm these preliminary results. The elucidation of functions and functional pathways for the WFS1 gene product and variants will shed light on the effect of such disparate mutations on gene function and their role in the resulting clinical phenotype in WS and associated disorders.

Missense variations of the gene responsible for Wolfram syndrome (WFS1/wolframin) in Japanese: possible contribution of the Arg456His mutation to type 1 diabetes as a nonautoimmune genetic basis

Recently, a novel gene for a putative transmembrane protein (WFS1/wolframin) was found to be mutated in patients with Wolfram syndrome or DI-DM-OA-D (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness) syndrome. It is suggested that the WFS1 protein is important in the survival of islet beta-cells. We studied the WFS1 gene in a Japanese population to assess its possible role in common type 1 diabetes. Mutation screening revealed four missense mutations; R456H, G576S, H611R, and I720V. By genetic association studies of 185 type 1 diabetes patients and 380 control subjects, we found that R456H was significantly increased in the type 1 diabetes group compared to the control group (P = 0.0005); H611R and I720V were also significantly increased with weaker significance. Furthermore, in patients with the R456H mutation, type 1 diabetes-resistant HLA-DRB1 alleles (DRB1*0406, 1501, and 1502) were significantly increased compared to mutation-negative patients while susceptible DRB1*0901 was significantly decreased. Frequencies of autoimmunity characteristics (ICA or GAD-Ab positiveness and combination of autoimmune thyroid disease) were decreased in the R456H-positive patients compared to the R456H-negative patients. These data suggest that the WFS1 gene may have a role in the development of common type 1 diabetes as a nonautoimmune genetic basis.

Clinical and molecular genetic analysis of 19 Wolfram syndrome kindreds demonstrating a wide spectrum of mutations in WFS1

Wolfram syndrome is an autosomal recessive neurodegenerative disorder characterized by juvenile-onset diabetes mellitus and progressive optic atrophy. mtDNA deletions have been described, and a gene (WFS1) recently has been identified, on chromosome 4p16, encoding a predicted 890 amino acid transmembrane protein. Direct DNA sequencing was done to screen the entire coding region of the WFS1 gene in 30 patients from 19 British kindreds with Wolfram syndrome. DNA was also screened for structural rearrangements (deletions and duplications) and point mutations in mtDNA. No pathogenic mtDNA mutations were found in our cohort. We identified 24 mutations in the WFS1 gene: 8 nonsense mutations, 8 missense mutations, 3 in-frame deletions, 1 in-frame insertion, and 4 frameshift mutations. Of these, 23 were novel mutations, and most occurred in exon 8. The majority of patients were compound heterozygotes for two mutations, and there was no common founder mutation. The data were also analyzed for genotype-phenotype relationships. Although some interesting cases were noted, consideration of the small sample size and frequency of each mutation indicated no clear-cut correlations between any of the observed mutations and disease severity. There were no obvious mutation hot spots or clusters. Hence, molecular screening for Wolfram syndrome in affected families and for Wolfram syndrome-carrier status in subjects with psychiatric disorders or diabetes mellitus will require complete analysis of exon 8 and upstream exons.

A gene encoding a transmembrane protein is mutated in patients with diabetes mellitus and optic atrophy (Wolfram syndrome)

Wolfram syndrome (WFS; OMIM 222300) is an autosomal recessive neurodegenerative disorder defined by young-onset non-immune insulin-dependent diabetes mellitus and progressive optic atrophy. Linkage to markers on chromosome 4p was confirmed in five families. On the basis of meiotic recombinants and disease-associated haplotypes, the WFS gene was localized to a BAC/P1 contig of less than 250 kb. Mutations in a novel gene (WFS1) encoding a putative transmembrane protein were found in all affected individuals in six WFS families, and these mutations were associated with the disease phenotype. WFS1 appears to function in survival of islet beta-cells and neurons.

Wolfram (DIDMOAD) syndrome

Wolfram syndrome (MIM 222300) is the association of juvenile onset diabetes mellitus and optic atrophy, also known as DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness). Patients present with diabetes mellitus followed by optic atrophy in the first decade, cranial diabetes insipidus and sensorineural deafness in the second decade, dilated renal outflow tracts early in the third decade, and multiple neurological abnormalities early in the fourth decade. Other abnormalities include primary gonadal atrophy. Death occurs prematurely, often from respiratory failure associated with brainstem atrophy. Most patients eventually develop all complications of this progressive, neurodegenerative disorder. The pathogenesis is unknown, but the prevalence is 1 in 770000 in the UK and inheritance is autosomal recessive. A Wolfram gene has recently been mapped to chromosome 4p16.1, but there is evidence for locus heterogeneity, and it is still possible that a minority of patients may harbour a mitochondrial genome deletion. The best available diagnostic criteria are juvenile onset diabetes mellitus and optic atrophy, but there is a wide differential diagnosis which includes other causes of neurodegeneration.

Linkage of Wolfram syndrome to chromosome 4p16.1 and evidence for heterogeneity

Wolfram syndrome (DIDMOAD syndrome; MIM 222300) is an autosomal recessive neurodegenerative disorder characterized by juvenile-onset diabetes mellitus and bilateral optic atrophy. Previous linkage analysis of multiply affected families indicated that the gene for Wolfram syndrome is on chromosome 4p, and it produced no evidence for locus heterogeneity. We have investigated 12 U.K. families with Wolfram syndrome, and we report confirmation of linkage to chromosome 4p, with a maximum two-point LOD score of 4.6 with DRD5, assuming homogeneity, and of 5.1, assuming heterogeneity. Overlapping multipoint analysis using six markers at a time produced definite evidence for locus heterogeneity: the maximum multipoint LOD score under homogeneity was <2, whereas when heterogeneity was allowed for an admixture a LOD of 6.2 was obtained in the interval between D4S432 and D4S431, with the peak close to the marker D4S3023. One family with an atypical phenotype was definitely unlinked to the region. Haplotype inspection of the remaining 11 families, which appear linked to chromosome 4p and had typical phenotypes, revealed crossover events during meiosis, which also placed the gene in the interval D4S432 and D4S431. In these families no recombinants were detected with the marker D4S3023, which maps within the same interval.

A nuclear defect in the 4p16 region predisposes to multiple mitochondrial DNA deletions in families with Wolfram syndrome

Wolfram syndrome is a progressive neurodegenerative disorder transmitted in an autosomal recessive mode. We report two Wolfram syndrome families harboring multiple deletions of mitochondrial DNA. The deletions reached percentages as high as 85-90% in affected tissues such as the central nervous system of one patient, while in other tissues from the same patient and from other members of the family, the percentages of deleted mitochondrial DNA genomes were only 1-10%. Recently, a Wolfram syndrome gene has been linked to markers on 4p16. In both families linkage between the disease locus and 4p16 markers gave a maximum multipoint lod score of 3.79 at theta = 0 (P<0.03) with respect to D4S431. In these families, the syndrome was caused by mutations in this nucleus-encoded gene which deleteriously interacts with the mitochondrial genome. This is the first evidence of the implication of both genomes in a recessive disease.

Wolfram syndrome: hereditary diabetes mellitus with brainstem and optic atrophy

Wolfram syndrome was originally described as a combination of familial juvenile-onset diabetes mellitus and optic atrophy. Other neurological features subsequently emerged, and "DIDMOAD" (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness) became a commonly accepted acronym. Here, we describe 4 further cases from 2 families, in whom there occurred previously unrecognized neurological features, central apnea and neurogenic upper airway collapse, together precipitating primary respiratory failure (fatal in 1 case), startle myoclonus (in 2 unrelated cases), axial rigidity, and Parinaud's syndrome. Magnetic resonance images revealed striking brainstem atrophy affecting, in particular, the pons and midbrain. The mitochondrial DNA from 3 cases (and relatives) showed no evidence of any of the previously reported abnormalities. These neurological and neuroradiological features, in conjunction with (1) analyses showing the neurodegenerative origin of optic atrophy, deafness, diabetes insipidus, and incontinence, (2) other previously reported neurological complications (including anosmia, ataxia, epilepsy, and neuropsychiatric and cognitive abnormalities), and (3) the very small number of published postmortem studies, indicate that Wolfram syndrome should be reemphasized as a unique hereditary neurodegenerative disorder with prominent optic atrophy and diabetes mellitus.

Neurodegeneration and diabetes: UK nationwide study of Wolfram (DIDMOAD) syndrome

Wolfram syndrome is the association of diabetes mellitus and optic atrophy, and is sometimes called DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). Incomplete characterisation of this autosomal recessive syndrome has relied on case-reports, and there is confusion with mitochondrial genome disorders. We therefore undertook a UK nationwide cross-sectional case-finding study to describe the natural history, complications, prevalence, and inheritance of the syndrome. We identified 45 patients with Wolfram syndrome--a prevalence of one per 770,000. Non-autoimmune, insulin-deficient diabetes mellitus presented at a median age of 6 years, followed by optic atrophy (11 years). Cranial diabetes insipidus occurred in 33 patients (73%) with sensorineural deafness (28, 62%) in the second decade; renal-tract abnormalities (26, 58%) presented in the third decade followed by neurological complications (cerebellar ataxia, myoclonus [28, 62%]) in the fourth decade. Other abnormalities included gastrointestinal dysmotility in 11 (24%), and primary gonadal atrophy in seven of ten males investigated. Median age at death (commonly central respiratory failure with brain-stem atrophy) was 30 years (range 25-49). The natural history of Wolfram syndrome suggests that most patients will eventually develop most complications of this progressive, neurodegenerative disorder. Family studies indicate autosomal recessive inheritance with a carrier frequency of one in 354, an absence of a maternal history of diabetes or deafness, and an absence of the mitochondrial tRNA Leu (3243) mutation. Juvenile-onset diabetes mellitus and optic atrophy are the best available diagnostic criteria for Wolfram syndrome, the differential diagnosis of which includes other causes of neurodegeneration.

Mitochondrial mutation commonly associated with Leber's hereditary optic neuropathy observed in a patient with Wolfram syndrome (DIDMOAD)

DIDMOAD is usually considered an autosomal recessive condition, with wide phenotypic variation, but the possibility of mitochondrial mutations occurring in this condition has been considered. A 19 year old man presented with long standing diabetes mellitus, optic atrophy, and grand mal seizures. Further investigations showed unilateral sensorineural hearing loss and the most common mitochondrial DNA mutation associated with Leber's hereditary optic neuropathy, which was inherited from his mother. This suggests the DIDMOAD phenotype is a mitochondrial disorder in some cases and is likely to have a heterogeneous aetiology.

Diabetes secondary to genetic disorders

Diabetes may be associated with many genetic disorders. The scientific importance of these often rare disorders resides in the insight they may provide into the possible mechanisms of common diabetes. The type of diabetes varies in these syndromes. Non-insulin-dependent diabetes (NIDDM), clinically similar to common NIDDM, may be found in some syndromes (e.g. Werner's syndrome). In others there may be considerable insulin resistance, such as that present in ataxia telangiectasia. Extreme insulin resistance due to abnormal insulin receptor function is found in the Mendenhall syndrome. The mechanism of diabetes is more obscure in acute intermittent porphyria (AIP), although haem deficiency affecting the cytochrome chain raises interesting possibilities. In glycogen storage disease type I, the diabetes is associated with insulinopenia, following an earlier period in the disease when hypoglycaemia is the rule. IDDM, clinically similar to the common form, is present in the autoimmune polyglandular syndromes. Although a change in the lean:fat ratio is common in many neuromuscular disorders, mechanisms other than insulin resistance would seem to operate. The increased incidence of diabetes in heterozygotes for some of these genetic disorders raises the possibility that many common diabetics are, in fact, heterozygotes for some other disorder. The increased frequency of diabetes in Klinefelter's syndrome, Turner's syndrome and possibly Down's syndrome leads to the hypothesis that non-disjunction may, in some way be associated with the predisposition to diabetes. In several syndromes there is an increased incidence of diabetes in otherwise unaffected relatives of individuals with these syndromes. It is impossible to assess what proportion of common NIDDM or IDDM is made up of heterozygotes for these genetic syndromes.

Mutations in mitochondrial tRNA genes: non-linkage with syndromes of Wolfram and chronic progressive external ophthalmoplegia

We have recently identified a point mutation in the mitochondrially encoded tRNA(Leu(UUR)) gene which associates with a combination of type II diabetes mellitus and sensorineural hearing loss in a large pedigree. To extend this finding to other syndromes which exhibit a combination of diabetes mellitus and hearing loss we have sequenced all mitochondrial tRNA genes from two patients with the Wolfram syndrome, a rare congenital disease characterized by diabetes mellitus, deafness, diabetes insipidus and optic atrophy. In each patient, a single different mutation was identified. One is an A to G transition mutation at np 12,308 in tRNA(Leu(CUN)) gene in a region which is highly conserved between species during evolution. This mutation has been described by Lauber et al. (1) as associating with chronic progressive external ophthalmoplegia (CPEO). The other is a C to T transition mutation at np 15,904 in tRNA(Thr) gene. Both mutations are also present in the general population (frequency tRNA(Leu(CUN)) mutation 0.16, tRNA(Thr) mutation 0.015). These findings suggest that evolutionarily conserved regions in mitochondrial tRNA genes can exhibit a significant polymorphism in humans, and that the mutation at np 12,308 in the tRNA(Leu(CUN)) gene is unlikely to be associated with CPEO and Wolfram syndrome.

Diabetes insipidus, diabetes mellitus, optic atrophy and deafness (DIDMOAD syndrome). A clinical study in two Sudanese families

Four Sudanese children with DIDMOAD syndrome (diabetes insipidus, diabetes mellitus, optic atrophy and deafness) are reported. They were two boys (aged 15 and 16 years) in one family and a boy and a girl (aged 16 and 6 years, respectively) in another family. Diabetes mellitus was first to appear (at 3-8 years) followed by deafness and visual failure; and the disease ended fatally in one patient (aged 20 years). In the other three, diabetes insipidus was confirmed using water deprivation test for 8 hours. The maximum urine osmolality ranged between 131-523 mOsm/kg, whereas the corresponding plasma osmolality ranged between 315-332 mOsm/kg. Slight further improvement in urine concentration was observed in 2 of the patients following the use of desmopressin (DDAVP, 20 micrograms intranasally). Intravenous pyelography, voiding cystourethrography and ultrasound revealed severe bilateral hydronephrosis, dilated ureters and distended bladder without vesicoureteral reflux in the three patients. With the high rate of consanguinity prevalent in North Africa and the Middle East, we recommend examining children who present with diabetes mellitus in this region for features of DIDMOAD syndrome.

Wolfram's syndrome and HLA

A Sicilian family with three siblings affected by Wolfram's syndrome (Ws) is reported. HLA typing was performed in eight individuals from this family through three generations. Two of the three patients were HLA DR2 positive. The results suggest that the gene for Ws is not linked to the HLA region on chromosome 6, but located on some other chromosome, and that the allele HLA DR2 might predispose to the mutation responsible for Ws.

Optic atrophy in Wolfram syndrome

The clinical and electrophysiologic findings in 11 cases of Wolfram syndrome are presented. These findings suggest that optic atrophy in Wolfram syndrome is not secondary to retinal pathology, but probably represents part of a generalized degeneration of neural structures. The relationship of diabetes mellitus to this process of neural degeneration remains unclear.

DIDMOAD syndrome in a Libyan family

We report three Libyan children from one family with the syndrome diabetes insipidus, diabetes mellitus, optic atrophy and deafness, (DIDMOAD). Two children presented with diabetic ketoacidosis while one was discovered during screening of the family. All three children are alive, two of them on desmopressin (DDAVP) and insulin therapy and one on DDAVP only.

A variant of the "DIDMOAD" syndrome (diabetes insipidus, diabetes mellitus, optic atrophy and deafness)

A 29-year-old female with diabetes insipidus, deafness, a visual disorder and an abnormal glucose tolerance test, who gave birth to a healthy baby is described. Her male sibling is probably also similarly affected. These patients may represent previously unreported variants of the "DIDMOAD" (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness) syndrome. This is the first reported case of childbirth in an affected patient.

Association of diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. The Wolfram or DIDMOAD syndrome

Seven patients with a rare syndrome of diabetes insipidus (DI), diabetes mellitus (DM), optic atrophy (OA), neurosensory deafness (D), atony of the urinary tract, and other abnormalities (Wolfram or DIDMOAD syndrome) are reported. Of the seven patients, three siblings were followed up for 10-17 years. All seven patients had diabetes mellitus and optic atrophy; six had diabetes insipidus; and in the four patients investigated there was dilatation of the urinary tract. The severity of diabetes varied, and all required insulin for control of the hyperglycaemia. In one patient the course of the disease simulated maturity onset diabetes of the young; another presented with ketoacidosis; but none had haplotypes usually associated with insulin dependent diabetes mellitus. The diabetes insipidus responded to chlorpropamide, suggesting partial antidiuretic hormone deficiency. Onset of optic atrophy and loss of vision occurred relatively late and progressed slowly, although in one patient there was a rapid deterioration in visual acuity. Deafness was mild, of late onset, and of sensorineural origin. A degenerative process affecting the central and peripheral nervous system can explain all the manifestations of the syndrome except diabetes mellitus. The pathogenesis of the diabetes mellitus remains obscure.

Observation concerning the age of onset and the nature of optic atrophy in Wolfram's syndrome (DIDMOADS)

A 31/2-year-old boy, who was diagnosed to have diabetes 6 months earlier, was referred for routine fundus check-up. No family history of diabetes was known. Ophthalmologic findings were: slight hyperopic astigmatism, visual acuity right = left = 1/5, examination of the visual field not yet possible, optic atrophy, no diabetic retinopathy, very narrow vessels. ERG: distinctly reduced potentials. Audiogram: loss of high tones in the inner ear. Pediatric examination ruled out other endocrine disorders, no symptoms of diabetes insipidus were found. These results perhaps reveal the nature of the optic atrophy: a retinal one. The authors found no other ERGs in the literature at such an early stage.

Dominant optic atrophy, deafness, ptosis, ophthalmoplegia, dystaxia, and myopathy. A new syndrome

Twenty-three members of a 96-member family exhibited an autosomal dominant disorder which has not previously been described. This disorder involves progressive optic atrophy, abnormal electroretinography without retinal pigment changes, and progressive sensorineural hearing loss usually evident in the first or second decade of life. In midlife, ptosis, ophthalmoplegia, dystaxia, and a nonspecific myopathy occur.