Mutations in a newly identified GTPase gene cause autosomal dominant hereditary spastic paraplegia

The hereditary spastic paraplegias (HSPs; Strümpell-Lorrain syndrome, MIM number 18260) are a diverse class of disorders characterized by insidiously progressive lower-extremity spastic weakness (reviewed in refs. 1-3). Eight autosomal dominant HSP (ADHSP) loci have been identified, the most frequent of which is that linked to the SPG4 locus on chromosome 2p22 (found in approximately 42%), followed by that linked to the SPG3A locus on chromosome 14q11-q21 (in approximately 9%). Only SPG4 has been identified as a causative gene in ADHSP. Its protein (spastin) is predicted to participate in the assembly or function of nuclear protein complexes. Here we report the identification of mutations in a newly identified GTPase gene, SPG3A, in ADHSP affected individuals.

Prenatal diagnosis of hereditary spastic paraplegia

Hereditary spastic paraplegia (HSP) is a degenerative neurologic disorder that causes progressive, often severe, spastic weakness in the legs. Autosomal dominant HSP is a highly penetrant, genetically heterogeneous disorder with loci present on chromosomes 2p21-24, 2q24-34, 8q23-24, 10q23.3-24, 12q13, 14q12-23, 15q11-14 and 19q13.1. We identified a large HSP kindred in which the disorder was tightly linked to chromosome 14q12-23. We tested chorionic villus DNA samples of two at-risk fetuses for inheritance of microsatellite polymorphisms flanking and within this locus that segregated with the disease in this family. Whereas samples from the first fetus showed inheritance of a haplotype segregating with the disease allele (indicating high risk of developing HSP), samples from the second fetus showed inheritance of a haplotype segregating with the normal allele (indicating low risk of developing HSP). This is the first report of prenatal testing for HSP. Published in 2001 by John Wiley & Sons, Ltd.

[Aldose reductase gene polymorphism and rate of appearance of retinopathy in non insulin dependent diabetics]

BACKGROUND

Recent studies suggest that polymorphisms associated to the aldose reductase gene could be related to early retinopathy in noninsulin dependent diabetics (NIDDM). There is also new interest on the genetic modulation of coagulation factors in relation to this complication.

AIM

To look for a possible relationship between the rate of appearance of retinopathy and the genotype of (AC)n polymorphic marker associated to aldose reductase gene.

PATIENTS AND METHODS

A random sample of 27 NIDDM, aged 68.1 +/- 10.6 years, with a mean diabetes duration of 20.7 +/- 4.8 years and a mean glycosilated hemoglobin of 10.6 +/- 1.6%, was studied. The genotype of the (AC)n, polymorphic marker associated to the 5' end of the aldose reductase (ALR2) gene was determined by 32P-PCR plus sequenciation. Mutations of the factor XIII-A gene were studied by single stranded conformational polymorphism, sequenciation and restriction fragment length polymorphism.

RESULTS

Four patients lacked the (AC)24 and had a higher rate of appearance of retinopathy than patients with the (AC)24 allele (0.0167 and 0.0907 score points per year respectively, p = 0.047). Both groups had similar glycosilated hemoglobin (11.7 +/- 0.2 and 10.5 +/- 1.6% respectively). Factor XIII gene mutations were not related to the rate of appearance of retinopathy.

CONCLUSIONS

Our data suggest that the absence of the (AC)24 allele of the (AC)n polymorphic marker associated to the 5' end of the aldose reductase gene, is associated to a five fold reduction of retinopathy appearance rate.

Novel locus for autosomal dominant hereditary spastic paraplegia, on chromosome 8q

Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of disorders characterized by insidiously progressive spastic weakness in the legs. Genetic loci for autosomal dominant HSP exist on chromosomes 2p, 14q, and 15q. These loci are excluded in 45% of autosomal dominant HSP kindreds, indicating the presence of additional loci for autosomal dominant HSP. We analyzed a Caucasian kindred with autosomal dominant HSP and identified tight linkage between the disorder and microsatellite markers on chromosome 8q (maximum two-point LOD score 5.51 at recombination fraction 0). Our results clearly establish the existence of a locus for autosomal dominant HSP on chromosome 8q23-24. Currently this locus spans 6.2 cM between D8S1804 and D8S1774 and includes several potential candidate genes. Identifying this novel HSP locus on chromosome 8q23-24 will facilitate discovery of this HSP gene, improve genetic counseling for families with linkage to this locus, and extend our ability to correlate clinical features with different HSP loci.

[Enteral nutrition in severe ulcerative colitis. Digestive tolerance and nutritional efficiency]

BACKGROUNDS AND AIMS

Total parenteral nutrition (TPN) has been traditionally used as an adjunctive therapy in severe ulcerative colitis patients. We performed a prospective study to ascertain the safety, nutritional efficiency, tolerance and costs of total enteral nutrition in this situation.

METHODS

After 48 hours of intensive medical treatment, severe ulcerative colitis patients initiated enteral feeding with a polymeric formula. The formula concentration and volume were increased daily.

RESULTS

17 patients (7 women, 10 men; age 36.8 +/- 12.8 years) with a mean clinical activity score of 15.6 +/- 1.5 were included. In 14 patients (82.4%) enteral nutrition was well tolerated, attaining in 11 of them more than 80% of the caloric requirements by day 4. In 3 cases we observed vomiting and bloating. Prealbumin levels improved significantly from 11.1 +/- 3.4 mg/dl to 22.7 +/- 6.8 mg/dl (p = 0.002) at the end of enteral nutrition (11.8 +/- 4.7 days). Albumin and other nutritional parameters did not change.

CONCLUSIONS

Total enteral nutrition could be considered a safe and well tolerated nutritional support in these patients. Although albumin and other nutritional parameters did not change during the study period, the increase in prealbumin levels suggests a favourable anabolic effect of total enteral nutrition.

Observations of ozone-induced foliar injury on black cherry (Prunus serotina, var. capuli) within the Desierto de Los Leones National Park, Mexico City

A survey for ozone-induced foliar injury of black cherry was conducted in mid-June 1995 within the Desierto de Los Leones National Park located southwest of Mexico City. Evaluations of the upper and lower tree crowns of 18 trees revealed evidence of significant upper surface stipple, leaf reddening and premature senescence on 72% of the trees. A general survey of an additional 169 trees disclosed that 41% exhibited similar symptoms. A gradient of increasing symptoms with increasing elevation was also evident. For the most part, asymptomatic trees were observed to be situated within well-shaded coves at the lower elevations with very few symptomatic trees present in these areas.

[Takayasu arteritis: usefulness of radiologic and angiographic studies]

With the purpose of learning the usefulness of radiologic and angiographic procedures for the evaluation of Takayasu's arteritis (TA), we studied 64 patients (ratio women: 8.1, average age: 23.5 years, range: 13-52 years) in which we performed arteriographic studies in the clinically affected area. All cases had chest films: 53 had thoracic aortogram, 60 abdominal aortogram, 16 pulmonary arteriography. According to the topography of the lesions we found 8% of the cases with damage exclusive to the supra-aortic trunk, 6% with isolated alteration of the intermediate thoraco-abdominal aorta, 62% with mixed pathology of the two categories above, and 21% with lesions in the pulmonary artery besides systemic arteriopathy. The results were as follows: 1) radiology of the chest: cardiomegaly (48%), irregularities in the ascending aorta (31%), calcification in the aortic wall (29%), calcified granulomas (25%) and signs of pulmonary venous hypertension (21%); 2) thoracic aortogram: irregularities in the descending aorta (56.6%), thickening of the wall of descending aorta (39.6%), dilatation of the ascending aorta (26.4%), of the descending aorta (26.4%); occlusions: of the left subclavian (24 cases), left mammary (16 cases), left carotid (8 cases) and left vertebral (8 cases); 3) abdominal aortogram: irregularities of the outline, stenosis, prominent "supplementary" arteries and aneurysms in 53%, 43.3%, 38% and 13.3 of the studies performed. The arteries most commonly affected were: renal (74.7%), both (31.6%), right (28.2%) and left (14.9%), superior mesenteric (26.6%) and hepatic (21.6%); 4) pulmonary arteriography: arterial occlusions: right superior lobar branch (37.5%), right medial (6.2%), right inferior (12.5%), without predilection by any lobe; 5) coronary arteriography: one case with occlusion of anterior descending artery and circumflex coronary artery (the other 8 cases without significant lesions). We concluded that TA affects independently the arteries of different areas, hence it is necessary to perform multiple angiographic studies for adequate evaluation of the extension of vascular damage.