COL4A1 mutations and hereditary angiopathy, nephropathy, aneurysms, and muscle cramps

BACKGROUND

COL4A3, COL4A4, and COL4A5 are the only collagen genes that have been implicated in inherited nephropathies in humans. However, the causative genes for a number of hereditary multicystic kidney diseases, myopathies with cramps, and heritable intracranial aneurysms remain unknown.

METHODS

We characterized the renal and extrarenal phenotypes of subjects from three families who had an autosomal dominant hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC), which we propose is a syndrome. Linkage studies involving microsatellite markers flanking the COL4A1-COL4A2 locus were performed, followed by sequence analysis of COL4A1 complementary DNA extracted from skin-fibroblast specimens from the subjects.

RESULTS

We identified three closely located glycine mutations in exons 24 and 25 of the gene COL4A1, which encodes procollagen type IV alpha1. The clinical renal manifestations of the HANAC syndrome in these families include hematuria and bilateral, large cysts. Histologic analysis revealed complex basement-membrane defects in kidney and skin. The systemic angiopathy of the HANAC syndrome appears to affect both small vessels and large arteries.

CONCLUSIONS

COL4A1 may be a candidate gene in unexplained familial syndromes with autosomal dominant hematuria, cystic kidney disease, intracranial aneurysms, and muscle cramps.

Phenotypic expression of the DYT1 mutation: a family with writer's cramp of juvenile onset

Recently, the mutation causing early-onset generalized torsion dystonia has been identified as a GAG deletion in the gene for an adenosine triphosphate-binding protein named torsinA. We describe a German family with 5 clinically affected individuals carrying this mutation. In at least 4 of the 5 patients, the disease presented as a dystonic writer's cramp during late childhood or adolescence, which affected sequentially both sides but did not progress to a generalized form of dystonia. We conclude that familial writer's cramp may be a manifestation of the DYT1 mutation.

A single family with writer's cramp, essential tremor, and primary writing tremor

We studied seven members of a family who had different types of movement disorders: Two had typical essential tremor, two (twins) had typical writer's cramp, one had both essential tremor and writer's cramp, one had primary writing tremor, and one (deceased) had uncharacterized tremor. This appears to be the first report of writer's cramp in twins and in so many family members. This family links together primary writing tremor, essential tremor, and writer's cramp and may help resolve the apparent controversy about the relationship of primary writing tremor to essential tremor and writer's cramp.

Progressive exercise intolerance associated with a new muscle-restricted nonsense mutation (G142X) in the mitochondrial cytochromeb gene

We report a novel nonsense mitochondrial cytochrome b mutation (G15170A) in a 40-year-old woman with progressive exercise intolerance and lactic acidosis. Muscle biopsy showed several cytochrome c oxidase-positive ragged-red fibers, and reduced activities of respiratory chain complexes I and III. This mutation, resulting in the loss of 228 amino acids of the protein, was very abundant in the patient's muscle, but undetectable in lymphocytes and fibroblasts. Clinical and laboratory data indicate that this defect is the primary cause of the disease, thus adding a new mutation in the cytochrome b gene among the growing number of patients with exercise intolerance and lactic acidosis.

Dominantly transmitted focal dystonia in families of patients with musician's cramp

Musician's dystonia is generally considered a sporadic disorder. We present three families with the index patient affected by musician's dystonia, but other forms of upper limb focal task-specific dystonia (FTSD), mainly writer's cramp, in seven relatives. Our results suggest a genetic contribution to FTSD with phenotypic variability, including musician's dystonia.

Early myocardial disease and cramping myalgia in Becker-type muscular dystrophy: a kindred

We present a clinical and morphological study concerning a kindred with slowly progressive X-linked muscular dystrophy (Becker type). Five males were affected; one died of heart failure at age 16. Severe and early cardiac disorder is unusual in this type of muscular dystrophy, and death at such an early age had not been reported previously. In the other patients of the kindred, cardiac abnormalities, if present at all, were nonspecific. Another unusual feature in this kindred was severe muscle pain at an early stage of the disease, a feature that cannot yet be explained.

Molecular genetic studies of muscle lactate dehydrogenase deficiency in white patients

We identified two new mutations in 2 white patients with muscle lactate dehydrogenase deficiency. Both patients had exercise intolerance, cramps, and recurrent myoglobinuria. One patient was homozygous for a 2-bp deletion in exon 5, resulting in a frameshift with premature termination of translation. The second patient was homozygous for a G-->A substitution at the 3' end of exon 2, leading to exon skipping and splicing of exon 1 to exon 3; the aberrantly spliced messenger RNA contains a frameshift, resulting in premature termination of translation. The present report provides evidence of molecular genetic heterogeneity in white patients with muscle lactate dehydrogenase deficiency.

Significance of Beevor's sign in facioscapulohumeral dystrophy and other neuromuscular diseases

An atypical presentation of facioscapulohumeral dystrophy (FSH) is described, where the presence of a positive Beevor's sign led to genetic testing and subsequent probable diagnostic confirmation. This prompted evaluation of a further 68 patients for the presence of Beevor's sign. Among these, 19/20 patients with FSH had a positive Beevor's sign, compared with 2/28 with other muscle diseases, and 0/20 in a neurological control group. Beevor's sign should be considered as an additional criterion for the diagnosis of FSH.

Familial cramp due to potassium-aggravated myotonia

Clinical, electrophysiological, and molecular genetic features were investigated in two patients from a family a with dominantly inherited myotonic disease, characterised by painful cramps, stiffness without weakness, fluctuation of symptoms, and cold sensitivity. A reduction in amplitude of the compound muscle action potential was demonstrated on cooling and administration of potassium, although no clinical exacerbation was seen. A heterozygote mutation Val1589Met was identified in the alpha-subunit of the skeletal muscle sodium channel gene in both patients, consistent with the diagnosis of potassium-aggravated myotonia. The phenotype in this family is much milder than that previously described in another family with a mutation at this site.

Familial nocturnal cramping

A familial syndrome of painful nocturnal cramping and jerking in members of three generations is described. All-night polysomnograms demonstrated both myoclonic jerks and sustained muscular activity in three family members, a 4-year-old girl, who presented with frequent episodes of painful awakenings; her 7-year-old brother, who had similar but less severe symptoms; and the 28-year-old mother, who had suffered nocturnal cramping and awakenings for much of her life. To the authors' knowledge, this is the first description of a familial disorder characterized by exclusively nocturnal intermittent cramping and myoclonus of brainstem or spinal origin.

Exercise-induced cramp, myoglobinuria, and tubular aggregates in phosphoglycerate mutase deficiency

We report two patients in whom phosphoglycerate mutase (PGAM) deficiency was associated with the triad of exercise-induced cramps, recurrent myoglobinuria, and tubular aggregates in the muscle biopsy. Serum creatine kinase (CK) levels were elevated between attacks of myoglobinuria. Forearm ischemic exercise tests produced subnormal increases of venous lactate. Muscle biopsies showed subsarcolemmal tubular aggregates in type 2 fibers. Muscle PGAM activities were markedly decreased (3% of the normal mean) and molecular genetic studies showed that both patients were homozygous for a described missense mutation (W78X). A review of 15 cases with tubular aggregates in the muscle biopsies from our laboratory and 15 cases with PGAM deficiency described in the literature showed that this clinicopathological triad is highly suggestive of PGAM deficiency.

Hereditary persistent distal cramps

A disease consisting of persistent muscle cramps involving distal muscle groups that occurred in 12 members of the same family is described. The cramps appeared on exertion and in full relaxation or during sleep. In the third generation they appeared in the second decade; in the fourth and fifth generations in childhood with higher frequency and intensity of cramps. The disease is not sex linked and seems to be dominantly inherited. Electromyography showed no myotonic response on insertion. Motor unit potentials were normal. Continual waxing and waning electrical discharges corresponding to clinically visible contractions of parts of the muscles were present. Repetitive nerve stimulation caused no change in the amplitude of evoked muscle potentials. On spinal anaesthesia or nerve block the muscle contractions continued but became painless. The movements were only stopped with local infiltration of anaesthetic into the muscle. There were no cramps on ischaemic work. Drug studies revealed no benefit on carbamazepine, slight relief with meprobamate, and complete disappearance with potassium chloride. The remission outlasted the treatment for three months and then cramps of milder degree reappeared. Repeated potassium chloride treatment was not effective. The cramps increased on hydrochlorothiazide, and 12 hours after spinal anaesthesia. In the authors' opinion the disease should be considered as not belonging to any known nosological entity.

Combined partial deficiency of muscle carnitine palmitoyltransferase and carnitine with autosomal dominant inheritance

The authors studied a 53 year old woman and her 22 year old son with episodes of paroxysmal muscle cramps and dark urines lasting several hours related to high fat diet and strenuous physical exercise beginning on both at age 14 years. The father, paternal uncle, paternal grandfather and another son of the mother also had paroxysmal muscle cramps. The two studied cases showed normal findings for physical evaluation, blood lactate after ischemic exercise, and muscle histology (light and electron microscopy). The serum creatine kinase was elevated in the son and normal in the mother. However, 72 hour fasting significantly raised the serum creatine kinase level in both cases. Plasma concentration of ketone bodies and acid soluble acyl-carnitine increased normally with prolonged fasting. The biochemical evaluation of the muscle tissue revealed intact anaerobic glycolysis and normal glycogen content but combined partial deficiency of muscle carnitine palmitoyltransferase and carnitine in both cases.

Search for a founder mutation in idiopathic focal dystonia from Northern Germany

Both the discovery of the DYT1 gene on chromosome 9q34 in autosomal dominant early-onset torsion dystonia and the detection of linkage for one form of adult-onset focal dystonia to chromosome 18p (DYT7) in a family from northern Germany provide the opportunity to further investigate genetic factors in the focal dystonias. Additionally, reports of linkage disequilibrium between several chromosome 18 markers and focal dystonia, both in sporadic patients from northern Germany and in members of affected families from central Europe suggest the existence of a founder mutation underlying focal dystonia in this population. To evaluate the role of these loci in focal dystonia, we tested 85 patients from northern Germany who had primary focal dystonia, both for the GAG deletion in the DYT1 gene on chromosome 9q34 and for linkage disequilibrium at the chromosome 18p markers D18S1105, D18S1098, D18S481, and D18S54. None of these patients had the GAG deletion in the DYT1 gene. Furthermore, Hardy-Weinberg analysis of markers on 18p in our patient population and in 85 control subjects from the same region did not support linkage disequilibrium. Taken together, these results suggest that most cases of focal dystonia in patients of northern German or central European origin are due neither to the GAG deletion in DYT1 nor to a proposed founder mutation on chromosome 18p but must be caused by other genetic or environmental factors.

Familial cramps and muscle pain

A family with a disorder characterized by muscle cramps that cause painful posturing of the hands and feet was studied. Three generations are affected and the trait is transmitted by autosomal dominant inheritance. The disorder begins in childhood and does not seem to be progressive. A primary abnormality in the motor neuron is suspected on the basis of electrophysiological studies.

Familial paroxysmal dystonic choreoathetosis: a family study

We interviewed and examined 12 members of a single family affected by paroxysmal dystonic choreoathetosis. Three subjects experienced characteristic painful dystonic spasms, often precipitated by cold and prolonged physical activity. Three other family members suffered painful cramping of their limbs, without involuntary movement, following physical exertion. Based on the clinical features of affected subjects, we suggest that exertional cramping may represent a "forme fruste" of paroxysmal dystonia.

Autosomal dominant cramping disease

A family was studied in which four generations (16 of 41 members) suffered from painful recurrent muscle cramping. A clear pattern of autosomal dominant inheritance was noted. The cramping first developed during adolescence or early adulthood. Electromyographic analysis indicated a neurogenic origin. The cramps seemed to be due to dysfunction of the motor neurons. The mechanisms underlying this alteration are unclear and require further investigation.

Haplotype analysis at the DYT1 locus in Ashkenazi Jewish patients with occupational hand dystonia

Genetic haplotypes at five marker loci that are closely linked to the DYT1 gene on chromosome 9q were determined in 10 Ashkenazi Jewish patients with focal hand dystonia (eight with musician's cramp, two with writer's cramp). The founder haplotype associated with > 90% of cases generalized dystonia in the Ashkenazi Jewish population could not be constructed from any of the twenty chromosomes. Potential haplotypes were determined, and no common haplotype was discerned in these patients. These findings argue against a role for the founder mutation in the DYT1 gene in the etiology of occupational hand dystonia in this ethnic group. Further, if the DYT1 gene is involved in these later onset dystonias, there is no evidence for a common mutation in the Ashkenazic Jewish population. It appears that excessive, repetitive use, possibly in combination with ulnar neuropathy, may serve as the inciting cause of some focal dystonias.

Kennedy disease in an Italian kindred

An X-linked adult-onset neurogenic muscular atrophy, chiefly proximal, with late involvement of the distal musculature and medulla oblongata was present in 4 members of a single kindred. Associated in all patients were gynecomastia, impotence and essential tremor. Frederickson type IV hyperlipemia was present in 1 patient. Hormonal stimulation tests in 2 patients elicited a borderline low testicular response in the younger of the 2 and a pathological response in the older patient. On the evidence of these and previously reported cases, Kennedy disease would appear to be characterized by an X-linked proximal neurogenic amyotrophy of adult onset and by a testicular endocrine deficit.

Familial muscle cramps with autosomal dominant transmission

A family is described with generalized muscle cramps inherited as an autosomal dominant trait and with maximal expression during adolescence. The age of onset varies between 10 and 15 years. Muscle enzymes are elevated with a peak level between 15 and 25 years. The complaints seem to disappear after the age of 25 years. EMG and muscle biopsies suggest a neurogenic origin of the cramps.

Hereditary neuropathy with liability to pressure palsies (HNPP) in a toddler presenting with toe-walking, pain and stiffness

The typical clinical presentation of hereditary neuropathy with liability to pressure palsies is an adult-onset recurrent, painless monoparesis. Electrophysiological abnormalities--decreased nerve conduction velocities and delayed distal latencies--can be detected even in asymptomatic patients. We describe a toddler, who presented with asymmetric toe walking, painful cramps and stiffness in the legs. He had calf hypertrophy, brisk tendon reflexes and bilateral Babinski signs and the electrophysiological examination was normal. The unlikely diagnosis of hereditary neuropathy with liability to pressure palsies was reached 5 years later, when the boy started to complain of episodic numbness and weakness in the upper extremities. His father, paternal aunt and grandmother had similar symptoms, but they had never been investigated. The typical 1.5 Mb deletion on chromosome 17p11.2-12 was found in our patient and his affected relatives.