Prevalence of hereditary motor and sensory neuropathy in Cantabria

Guillain-Barré syndrome in Cantabria, Spain. An epidemiological and clinical study

Seventy-one patients with Guillain-Barré syndrome (GBS) were retrospectively selected from within a defined area (Cantabria) in northern Spain, from 1975 to 1988. Excluding two non-resident cases, epidemiological analysis was based on 69 cases. The annual incidence rates were stable during the 14-year period of study with an average incidence of 0.95 (age-adjusted, 0.86) cases per 100,000 population. No significant difference was found for sex, urban or rural residence and there was no significant seasonal clustering. Antecedent event were recorded in 57% of patients, the most frequent events being upper respiratory infection and gastroenteritis. No association between use of gangliosides and the syndrome was found. Eight patients had variant syndromes including Fisher's syndrome (2 cases), and axonal (4 cases) and sensory (2 cases) GBS. Recurrences occurred in 3 cases. Excluding nine patients with incomplete follow-up and two with Fisher's syndrome, clinical analysis was based on 60 cases. Patients were divided into three groups as a function of their peak weakness. Significant features of the severe group were a requirement for ventilation, presence of bulbar palsy or dysautonomia and a longer duration of the plateau phase. However, it was not possible at an early stage of the clinical course to predict future motor deficit. Four (6.7%) patients belonging to the severe group died during the acute phase of the disease. No specific treatment for GBS was given. Outcome was assessed by means of serial examination up to 24 months after the onset of symptoms using a functional scale. At 3, 6 and 24 months 70%, 46% and 12% of patients, respectively, had a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Hereditary motor and sensory neuropathy type I: clinical and neurographical features of the 17p duplication subtype

Forty-four affected individuals, aged 8-68 years (mean 34 years), from six families with hereditary motor and sensory neuropathy type I (HMSN I, Charcot-Marie-Tooth disease type 1) were investigated to determine the clinical and electroneurographical characteristics of the HMSN I subtype that is defined by the presence of a DNA duplication on chromosome 17p. Motor nerve conduction velocity (MNCV) and, to a lesser extent, compound muscle action potential amplitude, were inversely related to clinical severity. Neither clinical severity nor MNCV were significantly related to age. These results suggest that the primary pathological process is not, or only slightly active after childhood.

A prospective study of stroke in young adults in Cantabria, Spain

BACKGROUND AND PURPOSE

The aim of this study was to determine the incidence, type, and prognosis of stroke in young adults in Cantabria, Spain.

METHODS

We investigated prospectively all patients aged 50 years or below who were admitted with the diagnosis of a stroke to the University Hospital "Marqués de Valdecilla" from April 1, 1986, to March 31, 1988. This is the main hospital of the region to which all patients with neurological problems are referred. These patients underwent a complete clinical and laboratory assessment for stroke and had 1-year mean follow-up.

RESULTS

The total series included 81 patients. The annual age-specific crude incidence rates of stroke were 17.3 and 10.4 per 100,000 for males and females, respectively. Twenty-four patients (30%) were diagnosed as having nonembolic cerebral infarction, 14 (17%) embolic cerebral infarction, 20 (25%) subarachnoid hemorrhage, 22 (27%) spontaneous cerebral hemorrhage, and one case (1%) cerebral venous thrombosis. Eighteen patients (22%) died within 30 days of the cerebrovascular event, and two others died during the follow-up period. Seventy-nine percent of the survivors recovered and were completely self-sufficient.

CONCLUSIONS

The incidence of stroke in the young found in Cantabria is comparable with that in previous studies. The initial hospital mortality was not negligible, but the prognosis among the survivors was favorable.

Charcot-Marie-Tooth disease in northern Sweden: an epidemiological and clinical study

One hundred four cases of Charcot-Marie-Tooth disease (CMT) in 52 families were identified within a defined area in northern Sweden corresponding to a prevalence rate of 20.1 cases per 100,000 (Dec 31 1991) for all subtypes. The prevalence of CMT type I was 16.2 per 100,000. The distribution of cases was not uniform. The prevalence rate is compared with previous prevalence studies focusing on Charcot-Marie-Tooth disease or hereditary motor and sensory neuropathy (HMSN). Three patients were classified as the distal spinal muscular atrophy type of CMT and one patient was not possible to classify. For seventy-five patients, available to clinical examination within the study, data were collected as to age at onset, symptoms, clinical findings and degree of disability.

Further evidence of a duplication in 17p11.2 in families with recurrence of HMSN Ia (Charcot-Marie-Tooth neuropathy type Ia)

Five Italian families with recurrence of cases of Charcot-Marie-Tooth disease (type Ia) were analysed using three closely linked DNA probes that detect polymorphisms in the region 17p11.2. The probe pVAW409R3 detected the presence of a duplication in all the affected subjects, but not in the subjects with normal electromyographic (EMG) findings. This observation confirms previous data indicating the association of the duplication with the disease, suggesting that, at least in populations of European origin, the duplication might be the molecular feature diagnostic of the pathological trait.

Estimation of the size of the chromosome 17p11.2 duplication in Charcot-Marie-Tooth neuropathy type 1a (CMT1a). HMSN Collaborative Research Group

We have previously shown a duplication in 17p11.2 with probe pVAW409R3 (D17S122) in 12 families with hereditary motor and sensory neuropathy type I (HMSN I) or Charcot-Marie-Tooth disease type 1 (CMT1). In this study we aimed to estimate the size of the duplication using additional polymorphic DNA markers located in 17p11.2-p12. Two other 17p11.2 markers, pVAW412R3 (D17S125) and pEW401 (D17S61), were found to be duplicated in all HMSN I patients tested. Furthermore, all HMSN I patients showed the same duplication junction fragment with probe pVAW409R3. On the genetic map the duplicated markers span a minimal distance of 10 cM while on the physical map they are present in the same NotI restriction fragment of 1150 kb. The discrepancy between the genetic and physical map distances suggests that the 17p11.2 region is extremely prone to recombinational events. The high recombination rate may be a contributing factor to the genetic instability of this chromosomal region.

Population frequencies of inherited neuromuscular diseases--a world survey

A survey of the world literature, involving over 150 reported studies, of the population frequencies of various inherited neuromuscular diseases has been carried out. Data are presented for the commoner forms of muscular dystrophy (Duchenne, Becker, facioscapulohumeral, limb girdle), myotonic dystrophy and congenital myotonias, proximal spinal muscular atrophies, and the hereditary motor and sensory neuropathies. A conservative estimate of the overall prevalence among both sexes is around 286 x 10(-6), that is 1 in 3500 of the population may be expected to have a disabling inherited neuromuscular disease presenting in childhood or in later life. If severe disorders manifest only in infancy and early childhood (e.g. Werdnig-Hoffmann disease and severe congenital muscular dystrophy) and the rare forms of dystrophy and myopathy are also included, then the overall prevalence could well exceed 1 in 3000.

Duplication in chromosome 17p11.2 in Charcot-Marie-Tooth neuropathy type 1a (CMT 1a). The HMSN Collaborative Research Group

Hereditary motor and sensory neuropathy type I (HMSN I) or Charcot-Marie-Tooth disease type 1 (CMT 1) is an autosomal dominant disorder of the peripheral nervous system characterized by progressive weakness and atrophy of distal limb muscles. In the majority of HMSN I families, linkage studies localized the gene (CMT 1a) to the pericentromeric region of chromosome 17. We have detected with probe pVAW409R3 (D17S122) localized in 17p11.2 a duplication, co-segregating with the disease in 12 HMSN I families. In these families the duplication was present in all 128 patients but absent in the 84 unaffected and 44 married-in individuals (lod score of 58.44 at zero recombination). Further, on one HMSN I family the disease newly appeared simultaneously with a de novo duplication originating from an unequal crossing-over event at meiosis. Since different allelic combinations were found segregating with the duplication in different families linkage disequilibrium was not a significant factor. These findings led us to propose that the duplication in 17p11.2 itself is the disease causing mutation in all the HMSN I families analyzed.

The application of nerve conduction and clinical studies to genetic counseling in hereditary motor and sensory neuropathy type I

One hundred and thirty two individuals at risk for hereditary motor and sensory neuropathy (HMSN) type I from 11 unrelated families were evaluated by physical examination. Motor conduction velocity (MCV) studies of median and/or peroneal nerves were performed on 99 of them. Seventy-three subjects were found to be affected. In all age categories including the first decade of life, the ratio of affected individuals at risk did not significantly differ from the expected 1:1 ratio; that is, penetrance of the gene was complete. The majority of affected members in the first decade had no clinical features considered diagnostic of peroneal muscular atrophy syndrome, and full clinical expression developed in the second decade. Marked slowing of MCV was already present in the early years of life, even as young as 6 months. Moreover serial MCV studies carried out throughout the first year of life in an affected girl showed no physiological increase in conduction velocity. For purposes of genetic counseling, our experience suggests that, starting from 6 months of age, a clinically and electrophysiologically normal subject has a zero risk of having inherited the HMSN type I gene. However given the limited numbers in this series, infants at risk with normal clinical evaluation and MCVs should be followed up yearly up to 5 years of age.