Congenital muscular dystrophy and severe central nervous system atrophy in two siblings

Severe degenerative features of the nervous system of a hitherto unknown kind, associated with a neuromuscular disorder with histopathological features of congenital muscular dystrophy, are reported in two female siblings. The clinical profile was characterized by generalized hypotonia followed by spastic tetraplegia, contractures, polyneuropathy, lack of cognitive development and progressive microcephaly. There was no involvement of the eyes. Neuropathological examination of the brain of one sibling, who died at the age of 30 months, revealed subtotal loss of neurons in the cerebral and cerebellar cortex and in the ventral pons, and secondary loss of myelin in the cerebral and cerebellar subcortical white matter. Sural nerve biopsy in the other sibling, who had a similar neurological affection, showed a lack of large myelinated fibers.This investigation is part of the research program Disorders of the Neuromuscular System of the University of Nijmegen     

The vibratory innocent heart murmur in schoolchildren: A case-control Doppler echocardiographic study

Summary In 810 schoolchildren (aged 5–14 years) the prevalence of a grade 1–3/6 vibratory innocent heart murmur (VIHM) is 41%. Restricted to a grade 2 or 3 VIHM, the prevalence is 14%, decreasing from 21% in the age-class 5–6 years to 8% for children 13–14 years of age. The prevalence of a grade 3 VIHM is 1%. Together with a matched control, 84 children with a grade 2 or 3 VIHM underwent further cardiologic examination including electrocardiography, phonocardiography, and Doppler echocardiography. A positive correlation was found between the presence of a VIHM and higher left ventricular voltages on the ECG, but within the normal range; lower heart rate; smaller diameter of the ascending aorta (AAO); and higher blood flow velocity and higher maximal acceleration of the blood flow in the LVOT and the AAO. In 40% of the children with a VIHM, a systolic aortic valve vibration was seen with a frequency 100 Hz and an amplitude 1 mm, whereas this type of vibration was present in only one case control. No significant difference was found concerning the prevalence of false tendons in the left ventricle, systolic and diastolic diameter of the left ventricle, systolic time intervals, and shortening fraction of the left ventricle. The VIHM is strongly associated with a smaller AAO, with higher velocity and acceleration of the blood flow in the LVOT and AAO, and with a vibratory phenomenon of the aortic valve, pointing towards the LVOT-aortic valve region as the site of origin of the VIHM.     

Sjögren-Larsson syndrome: clinical and MRI/MRS findings in FALDH-deficient patients

OBJECTIVE: To determine the spectrum of clinical and MRI/1H MRS features of patients with fatty aldehyde dehydrogenase (FALDH) deficiency. BACKGROUND: The Sjogren-Larsson syndrome (SLS) was originally defined as a clinical triad consisting of ichthyosis, spastic di- or tetralegia, and mental retardation, with autosomal recessive inheritance. By now, both the deficiency of the enzyme FALDH, and the genetic mutations on chromosome 17 responsible for this deficiency, have been identified. SLS, defined by fibroblast FALDH deficiency, seems to be a much broader syndrome. METHODS: The clinical findings of 11 FALDH-deficient patients of different ages and one patient with the characteristic SLS-like ichthyosis, but without FALDH deficiency, were evaluated in relation to their cerebral MRI, and to 1H MRS in six patients. RESULTS: The severity of neurologic symptoms showed considerable variation. Fundoscopic perifoveal glistening dots and the characteristic SLS-like ichthyosis were present in all patients. Serial MRI findings showed evidence of retarded myelination and a variable degree of dysmyelination. 1H MRS showed an accumulation of free lipids in the periventricular white matter, even before the stage of visible dysmyelination. CONCLUSIONS: The neurologic consequences of FALDH deficiency show considerable variation. The characteristic pattern of ichthyosis and retinal degeneration are seen consistently, yet they are not pathognomonic. MRI and 1H MRS findings suggest an accumulation of long-chain fatty alcohol intermediates, resulting in retarded myelination and dysmyelination.     

Nitric oxide and l-arginine cause an accumulation of utrophin at the sarcolemma: a possible compensation for dystrophin loss in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD), a severe X-linked recessive disorder which results in progressive muscle degeneration, is due to a lack of dystrophin, a membrane cytoskeletal protein. An approach to treatment is to compensate for dystrophin loss with utrophin, another cytoskeletal protein with over 80% homology with dystrophin. Utrophin is expressed, at the neuromuscular junction, in normal and DMD muscles and there is evidence that it may perform the same cellular functions as dystrophin. So, the identification of molecules or drugs that could up-regulate utrophin is a very important goal for therapy. We show that in adult normal and mdx mice (an animal model of Duchenne myopathy) treated with l-arginine, the substrate of nitric oxide synthase (NOS), a pool of utrophin localized at the membrane appeared and increased, respectively. In normal and mdx myotubes in culture, l-arginine, nitric oxide (NO), or hydroxyurea increased utrophin levels and enhanced its membrane localization. This effect did not occur with d-arginine, showing the involvement of NOS in this process. The NO-induced increase in utrophin was prevented by oxadiazolo-quinoxalin-1-one, an inhibitor of a soluble guanylate cyclase implicated in NO effects. These results open the way to a potential treatment for Duchenne and Becker dystrophies.     

Hereditary prothrombin deficiency presenting as intracranial haematoma in infancy

Hereditary deficiency of prothrombin is a rare autosomal recessive bleeding disorder, with severe bleeding diathesis in homozygotes, but rarely resulting in intracranial haematoma. We describe two infants of consanguineous parents, presenting with acute subdural haematoma. Because such haematomas in infancy are highly indicative of trauma caused by child battering and because the socio-economic status of the family was unstable, there was a suspicion of child battering. However, further investigations revealed a bleeding diathesis due to a prothrombin deficiency. DNA analysis of the prothrombin gene showed homozygosity for a novel mutation, substituting Lys for Glu at codon 7 and resulting in decreased specific clotting activity. We discuss the probability of bleeding diathesis versus child battering in the aetiology of intracranial haematoma.     

Histological characteristics of sternoclavicular beta 2-microglobulin amyloidosis and clues for its histogenesis

BACKGROUND: The pathogenesis of beta 2-microglobulin amyloidosis (A beta 2m) has yet to be fully elucidated. METHODS: We describe the distribution and extent of A beta 2m deposition and macrophagic infiltration in cartilage, capsule, and synovium of sternoclavicular joints obtained postmortem from 54 patients after 3 to 244 (median 46) months of dialysis. Twenty-four nonuremic patients served as a control group. The diagnosis of amyloidosis (A) rested on a positive Congo Red staining (typical birefringence) and that of A beta 2m on positive immunostaining of the A deposits with a monoclonal anti-beta 2m antibody. The size of A deposits was measured. RESULTS: A beta 2m was detected in 32 (59%), and non-beta 2m amyloid (Anon beta 2m) was detected in an additional 8 (15%) of the 54 dialyzed patients. A beta 2m deposits were present in the cartilage of all A beta 2m (+) patients (100%). They were localized solely in the cartilage in 27% of the cases, either as a thin patchy layer or as a continuous thicker layer (identified as stage I). A beta 2m was additionally present in the capsule and/or synovium without macrophages in 27% of the cases (identified as stage II). The correlation between the size of cartilaginous deposits and dialysis duration (P = 0.02) as well as with the prevalence (P = 0.03) and size of capsular deposits (P = 0.02) suggests that stage II is a later stage of A deposition. Clusters of macrophages were detected around capsular and synovial amyloid deposits in 46% of the cases (identified as stage III). The longer duration of dialysis in those with stage III as well as the relationship between the size of the A beta 2m deposits and the prevalence of macrophagic infiltration suggests that stage III is the last stage of A beta 2m deposition. Marginal bone erosions were observed in 9 out of 12 patients with stage III deposits. Their size was correlated with that of cartilaginous deposits (P = 0.01). Among the 24 control patients, Anon beta 2m was detected in 12 patients (cartilage 100%, capsule 8%, synovium 30%). CONCLUSIONS: The earliest stage of A beta 2m deposition occurs in the cartilage. A beta 2m subsequently extends to capsule and synovium. These two first stages do not require macrophage infiltration. Macrophages are eventually recruited around larger synovial or capsular deposits in the final stage. Marginal bone erosions develop in this late stage.     

Adult from of basal cell navevus syndrome: A family study

Summary A 32-year-old patient had marked reduction of visual acuity due to falciform folds of the retina and retinal detachment, and severe neurological abnormality: bilateral pyramidal involvement, fasciculation in all limbs and gait ataxia. Skull radiographs showed internal frontal hyperostosis; CT scan showed calcification of the falx cerebri, and multiple arachnoid cysts were shown by myelography. A naevoid lesion had previously been removed from the left forearm. There was a history of ophthalmological symptoms in the mother and the daughter of the propositus. His son has café au lait spot on the abdomen and dentigerous cysts. The diagnosis of an adult form of basal cell naevus syndrome with an autosomal dominant mode of inheritance is discussed.This work was supported by grants from the F.R.S.M. of Belgium no. 3.4543.77 (Prof. P. Danis) and no. 3.4538.76 (Prof. C. Coërs) and the Free University of Brussels     

Mitotic and meiotic stability of linear plasmids in yeast.

Circular recombinant DNA plasmids that contain autonomously replicating sequences (ARSs) are maintained in extrachromosomal form in transformed yeast cells. However, these plasmids are unstable, being rapidly lost from cells growing without selection. Although the stability of such a plasmid can be increased by the presence of yeast centromere DNA (CEN), even CEN plasmids are lost at a high rate compared to a bona fide yeast chromosome. Natural yeast chromosomes are linear molecules; therefore, we have asked if linearization can improve the stability of recombinant DNA plasmids. Linear plasmids with and without yeast CENs were constructed in vitro by using termini from the extrachromosomal ribosomal DNA (rDNA) of the ciliated protozoan Tetrahymena thermophila as "telomeres." These linear plasmids transformed yeast at high frequency and were maintained as linear extrachromosomal molecules during mitotic growth. Moreover, linear plasmids containing CENs were also transmitted through meiosis: these plasmids segregate predominantly 2+:2- at the first meiotic division, indicating that Tetrahymena rDNA termini can provide telomere function during yeast meiosis. Linear plasmids without CENs were about as stable in mitosis as the comparable circular plasmid. Thus, the Tetrahymena rDNA termini have no marked positive or negative effect on the mitotic stability of ARS plasmids. However, linear plasmids containing CENs are three to four times less stable in mitotic cells than circular CEN plasmids. This decrease in stability is not due to a functional change in the centromere itself; rather, linearization of a CEN plasmid has a direct detrimental effect on its mitotic stability. These results may reflect the existence of spatial constraints on the positions of centromeres and telomeres, constraints which must be satisfied to achieve stable segregation of chromosomes during mitosis.