Involvement of dorsal root ganglia in Fabry''s disease.

Bouts of shooting pain along the extremities are common in the early stages of Fabry's disease. No pathological explanation has been advanced to clarify the mechanism of such pain. In the present case neuronal storage of glycolipid was confined to dorsal root ganglia neurones only. It is suggested that this may explain the shooting pain in Fabry's disease. In hereditary sensory radicular neuropathy, familial dysautonomia, and tabes dorsalis, changes in dorsal root ganglia cells cause similar clinical signs and thus it may be concluded that shooting pains in Fabry's disease may be caused by damage to dorsal root ganglia neurones.     

Fabry''s disease

Fifteen hemizygotes and 30 heterozygotes have been diagnosed since our investigations of Fabry's disease were started 10 years ago. They belong mainly to three Danish families. Genetic counseling and prenatal diagnoses have been performed, and in vitro studies of cultured fibroblasts and endothelial cells have been made with special reference to enzyme therapy.     

Detection of Fabry''s disease heterozy. gotes by enzyme analysis in single fibroblasts after cell sorting

Single cells were sorted from cultured fibroblasts of five carriers of Fabry's disease using a cell sorter (FACS II). The alpha-galactosidase A activity in the single fibroblasts was assayed in nanoliter droplets with the help of quantitative microfluorimetric techniques. Two populations of fibroblasts were present in the carriers, one showing an alpha-galactosidase-A activity comparable to that of Fabry patients, and another with normal alpha-galactosidase-A activity. This provides evidence of X-inactivation at the alpha-galactosidase-A locus. Since X-inactivation occurs at random, a high number of single cells has to be assayed to increase the clinical reliability for carrier detection. The methodology as presented enables such an approach.     

Detection of heterozygotes for myotonic dystrophy

In 34 families the effectiveness of various methods (clinical examination, electromyography and slit lamp examination of the lens) for detecting heterozygotes for myotonic dystrophy has been assessed. In those families in which the index patient developed symptoms in infancy or childhood, most heterozygotes were recognised by early adult life. However, in the families of index patients who developed symptoms after the age of 20, the expected 50% incidence of clinically affected heterozygotes among fight degree relatives was not reached before the age of 40. Only in the early onset families may it be assumed that a relative who is clinically unaffected by age 20 years is at small risk of transmitting the disorder.     

An example of rapid prenatal diagnosis of Fabry''s disease usingmicrotechniques

In a pregnancy at risk for Fabry's disease, a prenatal diagnosis could be established 11 days after amniocentesis in the 15th week of pregnancy. This was possible by microchemical analysis of the αgalactosidase activity in isolated groups of 100–200 freeze-dried, cultured amniotic fluid cells. The results of this microassay were confirmed by (micro)biochemical analysis in cell homogenates from replicate cultures performed in two independent laboratories. Some problems in prenatal diagnosis of heterozygotes are discussed, as well as the possibilities of microchemical techniques for the more rapid prenatal diagnosis of other lysosomal storage diseases.     

Detection of ornithine transcarbamylase deficiency heterozygotes by measuring of urinary uracil

The importance of detecting heterozygosity for X-linked ornithine transcarbamylase deficiency is well known. Although the DNA analysis and the allopurinol loading tests are commonly used for this purpose, both methods require complicated procedures. In order to establish a simple test for detecting female heterozygotes, we examined the uracil and orotic acid in single-voided urine samples from 70 healthy women, and from 12 asymptomatic females with ornithine transcarbamylase deficiency. Based on the results of healthy women, we were able to determine a screening cut-off line of 11.9 micromol/mmol creatinine (mean +/- 1SD in logarithmic form) for uracil. Using this cut-off line, the sensitivity of OCT heterozygotes was 100%. We were also able to establish a second cut-off line of 28.9 micromol/mmol creatinine (mean +/- 3SD in logarithmic form) for diagnosis. Using this second cut-off line, the specificity of OCT heterozygotes was 100%. Our study has shown that the measurement of urinary uracil is a relatively simple and effective method for detecting female heterozygotes.     

Screening for the fragile X syndrome among mentally retarded males by hair root analysis

A noninvasive antibody test was used to identify male fragile X patients in special education schools, on the basis of the lack of FMRP in hair roots. We studied 300 males with mental retardation of unknown cause attending special schools. Patients were divided into two groups, based on the scores according to a fragile X check list (Group 1 /= 10 points). Group 2 consists of 51 males and only 5 males in this group showed no FMRP expression in hair roots within the abnormal range (91%). Fragile X diagnosis in these cases was confirmed by DNA analysis. None of the males scoring more than 10 on the check list was diagnosed positive for the fragile X syndrome using DNA analysis. With our antibody test on hair roots we did not detect a fragile X patient in Group 1. The FMRP antibody test on hair roots is suitable in a screening program for the fragile X syndrome among mentally retarded males attending special education schools.     

Detection of heterozygotes in both parents of homozygous patients with Von Willebrand's disease.

Three patients with severe Von Willebrand's disease are shown to be homozygotes. They were born from unaffected parents. New techniques using a factor-VIII-related antigen assay by the Laurell method and a ristocetin-induced platelet aggregation assay demonstrated abnormalities in these two tests in both parents of the probands. Factor-VIII-related of heterogotes could not be differentiated from normal factor-VIII-related antigen by the immunodiffusion technique, crossed immunoelectrophoresis, and filtration on a sepharose 4b column.     

Fabry''s disease: specific inclusions found on electron microscopy of fibroblast cultures

Electron microscopy of fibroblasts cultured from skin biopsies of two sibs with Fabry's disease has shown characteristic crystalline cytoplasmic inclusions.     

Attempted detection of heterozygotes for maple-syrup-urine disease

The production of ¹⁴CO₂ from [1-¹⁴C] leucine by isolated leucocytes from four females and three males heterozygous for maple-syrup-urine disease (M. S. U. D.) of classical phenotypc and from urban and rural control groups was determined. Although not significantly different, values tended to be lower for female than for male controls and for rural than for urban controls. The mean values for females (heterozygotes, and rural and urban controls) were not significantly different, and although the mean value for male heterozygotes was significantly less than the means for male controls and female obligate heterozygotes, some male controls had values within the hetero-zygote range. Thus, the unambiguous identification of heterozygotes in this kindred was not possible with this assay system.     

Clinical and electron microscopic studies of a case of glycolipid lipoidosis (Fabry''s disease)

A case of glycolipid lipoidosis (Fabry's disease) in a 27-year-old man is recorded. The case is unusual in that despite extensive disease evidenced by widespread skin lesions, ocular abnormalities, and proteinuria, renal function was only minimally impaired. Electron microscope studies of kidney and skin showed that most cells contained the characteristic lipid described in this condition.     

Detection of posttransplant minimal disease chronic myelogenous leukemia by bcr rearrangement analysis

Until recently, cytogenetic detection of the Philadelphia chromosome (Ph) was the only reliable test to diagnose chronic myelogenous leukemia (CML) and detect minimal disease or early relapse following treatment. However, the recently developed ability to detect the Ph chromosome as a rearrangement in the bcr gene of chromosome 22 permits identification of the leukemic clone comprising as little as 5% of the cell population. We present results of simultaneous cytogenetic and DNA rearrangement studies in 28 CML patients considered for or treated with bone marrow transplantation. Our results show that the molecular method is significantly more sensitive than the cytogenetic method in the detection of minimal disease Ph-positive clones.     

Human hair follicles may be used for population screening of heterozygotes of glucose-6-phosphate dehydrogenase deficiency

The carrier status for glucose-6-phosphate dehydrogenase deficiency can still be detected with the use of hair follicles after a period up to 10–14 days after plucking, even under conditions of temperature and humidity that are encountered in tropical countries, where the disease is most common. Furthermore, it is shown that the hair colour or age of the donor has no influence on the enzyme activity. As a consequence, the hair follicle is indeed suitable for screening in rural areas since mailing to existing medical centres is possible.