Neurological manifestations of Fabry disease in female carriers

Aseptic meningitis and Fabry disease

OBJECTIVE

Fabry disease is caused by enzymatic defects in alpha-galactosidase A that leads to the accumulation of glycosphingolipids throughout the body, resulting in a multisystemic disorder. The most common neurological manifestations are neuropathic pain, autonomic nervous system dysfunction and strokes, but some rarer neurological manifestations exist. Among these, aseptic meningitis is a possible complication. Our objectives were to measure the prevalence of this complication in a cohort of patients with Fabry disease, and to describe its clinical features.

METHODS

We conducted a retrospective review of Fabry disease patients followed at our tertiary referral center between 1995 and September 2023 with at least one episode of meningitis, and performed a systematic review to identify similar published cases.

RESULTS

Four patients out of 107 (3.7%) had at least one episode of aseptic meningitis. Our systematic review identified 25 other observations. The median age of these 29 patients was 29.0 years, the median cerebrospinal fluid leukocyte count was 24 cells/mm3 with a predominance of lymphocytes in 64.7% of cases. In 82.8% of the patients, the diagnosis of Fabry disease was unknown before the meningitis. Large artery stenosis was present in 17.2% of patients and 57.1% of patients had a recent stroke concomitant with the meningitis. Several differential diagnoses were evoked, such as multiple sclerosis or central nervous system vasculitis.

INTERPRETATION

Our study suggests that Fabry disease should be considered as a cause of aseptic meningitis. The pathophysiological mechanisms underlying meningeal inflammation remain largely unknown but may reflect the dysregulation of pro-inflammatory signaling pathways.

Neuropsychiatric Symptoms and Their Association With Sex, Age, and Enzyme Replacement Therapy in Fabry Disease: A Systematic Review

Patients suffering from Fabry disease (FD) have an increased risk of developing neuropsychiatric symptoms (NPS), mostly impairment in cognitive performance and depression. Single cases of psychosis have been reported, however, their association with FD can be coincidental. Furthermore, deficits in social functioning and adaptation as well as specific coping styles in FD patients were observed. Recent studies focused on a longitudinal course of the disease and identified risk factors associated with specific NPS. Since 2001, enzyme replacement therapy (ERT) has been available and in preliminary studies seems to improve cognitive impairment and adaptive skills. In this systematic review, we analyze the available literature on the NPS in FD and investigate if there are any differences in their distribution between males and females, children/adolescents and adults, and individuals treated with ERT and untreated. We discuss the role of the psychological, environmental, and molecular alterations and their correlation to psychiatric manifestations in FD. Finally, we would like to increase awareness of the spectrum of NPS in FD.

Fabry's Disease: Otoneurologic Findings in Twelve Members of One Family

Fabry's disease corresponds to an inherited disorder transmitted by an X-linked recessive gene. It generates a dysfunction of glycosphingolipid metabolism due to an enzymatic deficiency of α-galactosidase activity, resulting in glycosphingolipid deposits in all areas of the body. The clinical (heart, kidney, and central nervous system) manifestations are more severe in hemizygous boys than in heterozygous girls. They appear during childhood or adolescence: acroparesthesia, joint pain, angiokeratoma, corneal dystrophy, hypohydrosis or anhydrosis, and renal failure. The otoneurologic symptoms consist of hearing fluctuation, progressive unilateral or bilateral hearing loss, and episodes of vertigo or dizziness. Otoneurologic findings in 12 of 26 members of the same family are presented: the mother and 9 of her 12 children, as well as 2 of her 14 grandchildren: 4 healthy persons, 4 heterozygous female carriers, and 4 hemizygous male patients. Three of the male patients had fluctuation of hearing, sudden hearing loss, and episodes of vertigo and dizziness. The otoneurologic examinations showed a bilateral cochleovestibular deficit (n = 1), a right cochleovestibular deficit (n = 1), and a bilateral hearing loss combined with a right vestibular deficit (n = 1). Histopathologic evidence of glycosphingolipid accumulation in vascular endothelial and ganglion cells, as well as atrophy of the stria and spiral ligament, might explain the otoneurologic symptoms and findings.

Fabry’s Disease Presenting as Stroke in a Young Female

Background:

Fabry’s disease is an X-linked disorder, caused by a deficiency of the lysosomal enzyme α-galactosidase A which results in the accumulation of the glycosphingolipid, ceramide trihexose in the vascular endothelium and can lead to cerebral infarction. Male hemizygotes are generally more severely affected than heterozygote females. Clinical disease in females is thought to be due to unequal X chromosome inactivation.

Case:

A 19-year-old woman, who was previously well, presented with neurological deficits secondary to basal ganglia and pontine infarction. Extensive cardiac, arterial and hematologic investigations did not identify the etiology of her stroke. Muscle biopsy revealed endothelial lysosomal aggregates most consistent with a diagnosis of Fabry’s disease. The diagnosis was confirmed on the basis of molecular genotype analysis.

Discussion:

Inherited causes of stroke such as Fabry’s disease should be considered in young patients with stroke if an etiologic diagnosis is not reached after complete investigations. Muscle biopsy can assist with the diagnosis and guide further investigations. This report summarizes the biochemical and histological features of Fabry’s disease and the associated genetic abnormalities.

Neuropathic and cerebrovascular correlates of hearing loss in Fabry disease

Fabry disease, OMIM 301500, is a progressive multisystem storage disorder due to the deficiency of alpha-galactosidase A (GALA). Neurological and vascular manifestations of this disorder with regard to hearing loss have not been analysed quantitatively in large cohorts. We conducted a retrospective cross sectional analysis of hearing loss in 109 male and female patients with Fabry disease who were referred to and seen at the Clinical Center of the National Institutes of Health, Bethesda, MD, USA on natural history and enzyme replacement study protocols. There were 85 males aged 6-58 years (mean 31 years, SD 13) and 24 females aged 22-72 years (mean 42 years, SD 12). All patients underwent a comprehensive audiological evaluation. In addition, cerebral white matter lesions, peripheral neuropathy, and kidney function were quantitatively assessed. HL(95), defined as a hearing threshold above the 95th percentile for age and gender matched normal controls, was present in 56% [95% CI (42.2-67.2)] of the males. Prevalence of HL(95) was lower in the group of patients with residual GALA enzyme activity compared with those without detectable activity (33% versus 63%) HL(95) was present in the low-, mid- and high-frequency ranges for all ages. Male patients with HL(95) had a higher microvascular cerebral white matter lesion load [1.4, interquartile range (IQR) 0-30.1 +/- versus 0, IQR 0-0], more pronounced cold perception deficit [19.4 +/- 5.5 versus 13.5 +/- 5.5 of just noticeable difference (JND) units] and lower kidney function [creatinine: 1.6 +/- 1.2 versus 0.77 +/- 0.2 mg/dl; blood urea nitrogen (BUN): 20.1 +/- 14.1 versus 10.3 +/- 3.28 mg/dl] than those without HL(95) (P < 0.001). Of the females, 38% had HL(95). There was no significant association with cold perception deficit, creatinine or BUN in the females. Word recognition and acoustic reflexes analyses suggested a predominant cochlear involvement. We conclude that hearing loss involving all frequency regions significantly contributes to morbidity in patients with Fabry disease. Our quantitative analysis suggests a correlation of neuropathic and vascular damage with hearing loss in the males. Residual GALA activity appears to have a protective effect against hearing loss.

Fabry disease: Guidelines for the evaluation and management of multi-organ system involvement

Fabry disease is an X-linked metabolic storage disorder due to the deficiency of lysosomal alpha-galactosidase A, and the subsequent accumulation of glycosphingolipids, primarily globotriaosylceramide, throughout the body. Males with classical Fabry disease develop early symptoms including pain and hypohidrosis by the second decade of life reflecting disease progression in the peripheral and autonomic nervous systems. An insidious cascade of disease processes ultimately results in severe renal, cardiac, and central nervous system complications in adulthood. The late complications are the main cause of late morbidity, as well as premature mortality. Disease presentation in female heterozygotes may be as severe as in males although women may also remain asymptomatic. The recent introduction of enzyme replacement therapy to address the underlying pathophysiology of Fabry disease has focused attention on the need for comprehensive, multidisciplinary evaluation and management of the multi-organ system involvement. In anticipation of evidence-based recommendations, an international panel of physicians with expertise in Fabry disease has proposed guidelines for the recognition, evaluation, and surveillance of disease-associated morbidities, as well as therapeutic strategies, including enzyme replacement and other adjunctive therapies, to optimize patient outcomes.

La maladie de Fabry : l'atteinte vasculaire multi-organe pourrait également intéresser la cochlée

PURPOSE

Fabry disease is an inborn error of metabolism due to a deficient activity of the lysosomal enzyme alpha-galactosidase A. The enzyme defect leads to the systemic accumulation of neutral glycosphingolipids in tissues, mainly in the vascular endothelium.

STRONG POINT

The aim of this paper is to present a review of the auditory manifestations in Fabry disease, and to discuss hypothesis on the vascular origin of deafness.

PERSPECTIVES

Sensorineural hearing loss in Fabry disease could be the first documented vascular pathology of the inner ear.

Chiari type I malformation in four unrelated patients affected with Fabry disease

Fabry disease (FD) is an X-linked inborn error of metabolism resulting from the deficient activity of alpha-galactosidase A which leads to the widespread deposition of glycosphingolipids in lysosomes, and to ischemic complications involving kidneys, heart and brain. Among neurological symptoms, strokes and transient ischemic attacks (TIA) have been reported. A 30-year-old male patient, with FD, was referred to us for evaluation of a sudden episode of dizziness, with disequilibrium, and diplopia, in agreement with the diagnosis of a TIA. Head magnetic resonance imaging (MRI) showed no cerebrovascular involvement but revealed the presence of Chiari type I malformation (CMI). We subsequently performed head MRI in a cohort of 44 consecutive hemizygous male patients and seven heterozygous females affected with FD, and identified three additional cases (two males and one female) of CMI. Whether the association is coincidental or not will need further studies but our data suggest that CMI should be ruled out in all Fabry patients.

Clinical manifestations of Fabry disease in children: data from the Fabry Outcome Survey

BACKGROUND

Fabry disease is a rare X-linked disorder caused by deficient activity of the enzyme alpha-galactosidase A. This produces progressive lysosomal accumulation of globotriaosylceramide throughout the body, leading to organ failure and premature death.

AIM

Here, we present the clinical manifestations of Fabry disease in children enrolled in FOS--the Fabry Outcome Survey--a European database of the natural history of Fabry disease and the effects of enzyme replacement therapy with agalsidase alfa (Replagal).

METHODS

Currently, there are 545 patients in FOS, from 11 European countries. We analysed the baseline demographic and clinical characteristics of 82 of these patients (40 boys, 42 girls) who were below 18 y of age. The median age at evaluation (defined as the median age at entry into FOS) was 12.5 and 13.2 y for boys and girls, respectively.

RESULTS

The most frequent early clinical manifestations of Fabry disease were neurological (acroparaesthesiae, altered temperature sensitivity) and gastrointestinal symptoms (altered bowel habits and abdominal pain), which were documented in about 80% and 60% of patients, respectively, at the time of evaluation and subsequent entry into FOS. Tinnitus, vertigo, fatigue and angiokeratoma were present in over 40% of patients. Symptoms were noted in early childhood and occurred with similar frequency in boys and girls, although the onset of symptoms was 2-5 y later in girls than in boys. There was an approximately 3-y delay from onset of symptoms to diagnosis, and patients were frequently misdiagnosed.

CONCLUSION

Although the life-threatening complications of Fabry disease, such as stroke and renal and heart failure, are not seen in children, the present analysis shows that other symptoms are common and may have an impact on quality of life.

Megadolichobasilar anomaly with thrombosis in a family with Fabry's disease and a novel mutation in the α-galactosidase A gene

Fabry's disease is an X-linked lysosomal storage disorder. alpha-Galactosidase deficiency leads to accumulation of globotriaosylceramide mainly in endothelial and smooth muscle cells. Cerebrovascular symptoms with predominant affection of the vertebrobasilar circulation are one of the major sources of morbidity in Fabry's disease. We present a Hungarian family with Fabry's disease caused by a new mutation in the alpha-galactosidase A gene (GLA), and describe a variant expression of the disease. Megadolichobasilar anomaly was diagnosed in two male patients in the family who died of thrombosis. In another female patient who had suffered from disturbance of the vertebrobasilar circulation, a strongly dilated basilar artery without thrombosis was found at autopsy. Another three family members had basilar strokes and large and elongated basilar arteries on MRI. Genetic analysis disclosed a c.47T-->C missense mutation resulting in L16P in the amino acid sequence of the alpha-galactosidase protein. This report suggests that megadolichobasilar anomaly is potentially life-threatening, and that L16P is a disease-causing mutation in patients with Fabry's disease. Early enzyme replacement therapy may prevent the development of these irreversible cerebrovascular complications.

Blood group does not correlate with disease severity in patients with Fabry disease (α-galactosidase A deficiency)

Blood groups B and P1 are substrates for the lysosomal enzyme alpha-galactosidase A. Therefore, patients with alpha-Gal A deficiency and blood groups B or P1 may exhibit more severe disease. In 48 Fabry patients distribution of blood group was not different from that in the Dutch population. No patient had blood group B. Clinical symptoms did not differ between bloodgroup P1 or P2 patients. We conclude that blood groups B and P1 are not overrepresented in Dutch Fabry patients. Blood group P1 is not correlated with more severe disease and cannot be considered a significant risk factor.

Mendelian and mitochondrial disorders associated with stroke

Several hereditary disorders induce angiopathy in the intracranial cerebrovasculature and thus cause ischemic strokes. MELAS is a maternally inherited mitochondrial disorder that produces stroke-like events. Sickle cell disease, which is the result of a single base pair substitution, is a major cause of strokes in children. Homocystinuria, an autosomal recessive syndrome, produces premature atherosclerosis. Hereditary cerebroretinal vasculopathy is an autosomal dominant disorder that causes retinal and brain infarctions. Fabry disease is an x-linked disorder that can cause stroke in adults. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy is an autosomal dominant syndrome that is associated with ischemic stroke and migraine-like headaches. The clinical presentation, stroke pathophysiology, and gene defects associated with these heritable disorders are reviewed.

Local and global cerebral blood flow and glucose utilization in the alpha-galactosidase A knockout mouse model of Fabry disease

Fabry disease is an X-linked lysosomal disorder characterized by deficient alpha-galactosidase A activity and intracellular accumulations of glycosphingolipids, mainly globotriaosylceramide (Gb3). Clinically, patients occasionally present CNS dysfunction. To examine the pathophysiology underlying brain dysfunction, we examined glucose utilization (CMR(glc)) and cerebral blood flow (CBF) globally and locally in 18 brain structures in the alpha-galactosidase A gene knockout mouse. Global CMR(glc) was statistically significantly reduced by 22% in Fabry mice (p < 0.01). All 18 structures showed decreases in local CMR(glc) ranging from 14% to 33%. The decreases in all structures of the diencephalon, caudate-putamen, brain stem, and cerebellar cortex were statistically significant (p < 0.05). Global cerebral blood flow (CBF) and local CBF measured in the same 18 structures were lower in Fabry mice than in control mice, but none statistically significantly. Histological examination of brain revealed no cerebral infarcts but abundant Gb3 deposits in the walls of the cerebral vessels with neuronal deposits localized to the medulla oblongata. These results indicate an impairment in cerebral energy metabolism in the Fabry mice, but one not necessarily due to circulatory insufficiency.

Anderson-Fabry disease: clinical manifestations of disease in female heterozygotes

Anderson-Fabry disease is a rare, X-chromosomal lipid storage disorder caused by a deficiency of lysosomal alpha-galactosidase A. Clinical manifestations of Anderson-Fabry disease include excruciating pain in the extremities (acroparaesthesia), skin vessel ectasia (angiokeratoma), corneal and lenticular opacity, cardiovascular disease, stroke and renal failure, only renal failure being a frequent cause of death. Heterozygote female carriers have often been reported as being asymptomatic or having an attenuated form of the disease. To evaluate the spectrum of clinical signs in heterozygotes, a comprehensive clinical examination was performed on 20 carriers of Anderson-Fabry disease. This revealed that, in addition to the skin manifestation, various other clinical manifestations of the disease are present, including acroparaesthesia, kidney dysfunction, cerebrovascular disease, and gastrointestinal and heart problems. It therefore appears that Anderson-Fabry disease affects both hemizygotes and heterozyotes and therefore should be considered to be an X-linked dominant disease.

[Fabry disease. Clinical and genetic aspects. Therapeutic perspectives]

INTRODUCTION

This review presents the clinical and genetic aspects of Fabry disease, along with recent advances in research.

CURRENT KNOWLEDGE AND KEY POINTS

Fabry disease is an X-linked inborn error of metabolism due to a deficient activity of the lysosomal enzyme alpha-galactosidase A. The enzymatic defect leads to the systemic accumulation of neutral glycosphingolipids in plasma and tissues. Clinical manifestations in affected hemizygous males are primarily due to progressive disease of small vessels, including angiokeratoma, autonomic dysfunction, and lifelong debilitating pain. Renal failure and vasculopathy of the heart and brain lead to early demise in adulthood. Demonstration of alpha-galactosidase A deficiency in leukocytes or plasma is the definitive method for the diagnosis of affected hemizygous males. Most female carriers are clinically symptomatic, they may present isolated acroparesthesia, cardiac symptoms, or the characteristic benign corneal dystrophy. Due to random X-chromosomal inactivation, enzymatic detection of carriers is often inconclusive. A reliable molecular test for detection of heterozygosity is therefore highly desirable for accurate genetic counselling. The GLA gene has been mapped to chromosome Xq22, and cloned. Several studies have shown the molecular heterogeneity of the disease. Currently, no standard treatment exists for Fabry disease. Symptomatic treatment is provided as appropriate. In addition, renal transplantation or dialysis is available for patients experiencing end-stage renal failure.

FUTURE PROSPECTS AND PROJECTS

The ability to produce high doses of recombinant alpha-galactosidase A in vitro has opened the way to preclinical studies in the mouse model and led to the development of the first clinical trials with enzyme replacement therapy in patients with Fabry disease.

Identification of four novel mutations in five unrelated Korean families with Fabry disease

Fabry disease is a X-linked recessively inherited metabolic disorder, which results from the deficient activity of the lysosomal hydrolase alpha-galactosidase A leading to the systemic deposition of glycosphingolipids with terminal alpha-galactosyl moieties. Single-strand conformation polymorphism (SSCP) analysis was performed, followed by DNA sequencing of PCR amplified exons of the human alpha-galactosidase A gene in 5 unrelated Korean patients with classic Fabry disease. Five different mutations were identified; two nonsense mutations (Y86X and R342X), one missense mutation (D266N), and two small deletions (296del2 and 802del4). Except for R342X mutation, four were novel mutations (Y86X, D266N, 296del2, 802del4). A T to G transversion at nucleotide position 5157 in exon 2 caused a tyrosine-to-stop substitution at codon 86. A G to A transition at position 10287 in exon 5 substituted an asparagine for an aspartate at codon 266. Mutation 296del2 in exon 2 resulted in a frame shift with a stop signal at the 22th codon downstream from the mutation, whereas mutation 802del4 resulted in a stop codon at the site of 4 bp deletion. In addition, the 802del4 was found to be a de novo mutation. This is the first report on mutation analysis of the human alpha-galactosidase A gene in Korean patients with Fabry disease.

Neurology and the skin

As knowledge of pathophysiology grows, so does the refinement of diagnoses. Sometimes increased knowledge permits consolidation and unification. Unfortunately, at our present level of understanding, it usually demands proliferation of diagnostic categories. As tedious as this diagnostic splintering may seem, such is the price currently exacted of both the investigator and the clinician who seek to optimise management. Increased diagnostic refinement often requires inquiry into matters outside the bounds of one's specialty. Most often we turn to the radiologist or to the laboratory to narrow the differential diagnosis generated from the history and neurological examination. As we have shown, a useful intermediate step is extension of the physical examination to organs such as the skin, which are not the traditional preserve of the neurologist. That any text could confer the sophistication required for expert dermatological diagnosis is an unrealistic expectation. However, we hope that this review will encourage careful examination of the skin, hair, and nails by the neurological practitioner, with consideration of referral to a dermatologist when greater expertise is required.

Multi-system signs and symptoms in X-linked ataxia carriers

Neurological, auditory, vestibular and ocular motor examinations were performed on 3 definite and 3 possible heterozygous carriers of a previously described X-linked multi-system disorder with early childhood onset, rapid progression and a fatal outcome (Arts et al., 1993). The symptoms, i.e., delayed motor development, ataxia, hearing loss and subnormal intelligence, were so evident in 2 of the possible carriers that they could be redesignated as probable carriers. Other symptoms in the definite and probable carriers were clubfeet, dysarthria, intention tremor and abnormal gait, while their signs included dysdiadochokinesia, ataxic paraplegia, abnormal muscle tendon reflexes and extensor plantar responses. All the symptomatic carriers developed moderate-to-severe sensorineural hearing loss with normal stapedial reflexes and brain stem auditory evoked potentials (BAEPs) in those in whom this could be evaluated. Speech discrimination was disproportionally poor unilaterally in one case from whom no BAEPs could be obtained because of her degree of hearing loss. Various combinations were found of high gain of the vestibulo-ocular reflex, spontaneous nystagmus and directional preponderance of vestibularly evoked nystagmus, slowing, hypometria or multi-stepping of saccades, saccadic intrusions of eye movements (macro square wave jerks, double saccadic pulses), impairment of smooth pursuit eye movements and optokinetic nystagmus, and failure of visual fixation suppression of vestibularly evoked nystagmus. Such findings indicate major involvement of the (vestibulo)cerebellum and the vermis. MRI in one carrier showed mild cerebellar atrophy.

Cerebrovascular complications of Fabry's disease

Fabry's disease (FD) is a rare, sex-linked disorder resulting from alpha-galactosidase deficiency. Cerebrovascular complications have been reported in the literature but have not been systematically analyzed. We report 2 patients and review 51 previously reported cases (descriptive meta-analysis) to clarify the clinical, radiologic, and pathologic features. The average age at onset of cerebrovascular symptoms was 33.8 years for hemizygous individuals (n = 43) and 40.3 years of heterozygotes (n = 10). The most frequent symptoms and signs were as follows (in descending order of frequency): hemiparesis, vertigo/dizziness, diplopia, dysarthria, nystagmus, nausea/vomiting, head pain, hemiataxia, and ataxia of gait, in the hemizygote group; and memory loss, dizziness, ataxia, hemiparesis, loss of consciousness and hemisensory symptoms, in the heterozygote group. The vertebrobasilar circulation was symptomatic in 67% of the hemizygotes and 60% of the heterozygotes. Intracerebral hemorrhage was found in 4 patients (3 hemizygotes and 1 heterozygote). Elongated, ectatic, tortuous vertebral and basilar arteries were the most common angiographic and pathologic features. For the hemizygotes, the recurrence rate for cerebrovascular disease was 76% and the death rate was 55%; 86% of the heterozygotes had recurrent cerebrovascular event(s) and 40% died. The cerebrovascular manifestations of FD, in both hemizygotes and heterozygotes, are predominantly due to dilative arteriopathy of the vertebrobasilar circulation, frequently recur, and portend a poor prognosis.

Fabry's disease in a female carrier with bilateral thalamic infarcts: a case report and a family study

An unusual case of a young woman, heterozygote for Fabry gene is reported, who presented bilateral thalamic infarcts due to occlusions of central nervous system vessels. Three other members of her family were studied. Fabry's disease (angiokeratoma corporis diffusum) is included among the rare causes of ischemic stroke in young adults.

Genetic disorders that masquerade as multiple sclerosis

There are many genetic disorders that have signs and symptoms suggestive of multiple sclerosis and that may easily be overlooked in the evaluation of both adult and pediatric multiple sclerosis patients. The recognition of a genetic disorder as the cause of a patient's "multiple sclerosis" phenotype has important implications not only for the patient, but often also for others in the patient's family who may be at risk for the same disease. We present here a review of single gene disorders that can masquerade as multiple sclerosis. For each disorder, the major clinical and biochemical characteristics are discussed, together with the appropriate testing to screen for and confirm the diagnosis. In addition, guidelines are presented for when to suspect an underlying genetic condition in a patient with a diagnosis of definite or probable multiple sclerosis. The great variety of genetic disorders that can masquerade as multiple sclerosis and the many implications of a genetic diagnosis underscore the importance of recognizing genocopies of multiple sclerosis.

Etiology of stroke in children

Cerebrovascular disorders are more common than once suspected, and our ability to diagnose stroke in children has improved with the development of newer imaging techniques in recent years. Children have a wide array of risk factors that promote cerebral infarction or hemorrhage, and a likely cause can eventually be pinpointed in about two thirds of patients if a thorough diagnostic evaluation is performed. Ideally, a systematic evaluation should confirm the presence of a cerebrovascular lesion and also identify the cause, concentrating initially on the more common or treatable risk factors. Recognition of the cause of a child's stroke is important, because the likelihood of recurrence depends largely on the etiology and whether treatment is available.

A Fabry's disease heterozygote with a new mutation: biochemical, ultrastructural, and clinical investigations

A Fabry heterozygote with early clinical manifestations of this X linked disorder is described. Her symptoms, including febrile attacks, arthralgia, abdominal pain, and neurological signs, were characteristic of Fabry's disease hemizygotes. The neurological findings were compatible with a brain stem infarction. The diagnosis was confirmed by the finding of low activities of alpha-galactosidase A (alpha-galA) in plasma, lymphocytes, and cultured fibroblasts, and by the observation of typical lamellar inclusions in the lysosomes of cultured fibroblasts. Increased levels of ceramide trihexoside were also found by TLC of urine sediment. The family history gave no indication of Fabry's disease in the patient's relatives, and biochemical and ultrastructural investigations of their cells were also normal. Our findings therefore suggest that the defective gene in the heterozygote has resulted from a new mutation.

Otologic histopathology of Fabry's disease

Fabry's disease is a rare progressive X-linked recessive disorder of glycosphingolipid metabolism. The accumulation of glycosphingolipids occurs in virtually all areas of the body, including the endothelial, perithelial, and smooth-muscle cells of blood vessels, the ganglion cells of the autonomic nervous system, and the glomeruli and tubules of the kidney. Although otologic symptoms have been described in these patients, to our knowledge there have been no temporal bone histopathologic reports. We describe the clinical histories, audiometric results, and temporal bone findings of two patients with this rare disorder. Both patients demonstrated a bilateral sloping sensorineural hearing loss audiometrically. Middle ear findings of seropurulent effusions and hyperplastic mucosa were seen in all four temporal bones. Strial and spiral ligament atrophy in all turns, and hair cell loss mainly in the basal turns, were also common findings. The number of spiral ganglion cells was reduced in all temporal bones; however, evidence of glycosphingolipid accumulation was not observed in the spiral ganglia.

Mendelian etiologies of stroke

There are many genetic disorders associated with an increased risk for stroke that may easily be overlooked in the evaluation of both adult and pediatric acute stroke victims. The recognition of a genetic disorder as the cause of a stroke has important implications not only for the immediate care of the stroke victim, but often also for others in the patient's family who may be at risk for the same disease and for whom preventive measures sometimes can be taken. We present here a comprehensive review of genetic disorders associated with stroke in the nongeriatric age groups for which a causative role in the evolution of stroke has been recognized or is likely. For each disorder, the major clinical and biochemical characteristics as well as the probable pathogenetic mechanisms of stroke are discussed, together with the appropriate testing required to screen for and confirm the diagnosis. The great variety of genetic disorders and mechanisms causing stroke underscores the increasing importance of understanding genetic disease for appropriate diagnosis and treatment of a common clinical problem affecting both children and adults.

Peripheral nerve conduction in Fabry disease

Peripheral nerve conduction was studied in 34 members, aged 3 to 54 years, from three separate kindreds with Fabry disease. Nerve conduction velocity was prolonged in one-third (11 of 34) of the study group. Of the 9 control family members with normal plasma alpha-galactosidase levels, 8 had normal velocity. A 6-year-old girl with normal plasma and leukocyte alpha-galactosidase levels and absent corneal deposits had slightly lower than normal nerve conduction velocity. One of the 3 obligate female carriers and 1 of 10 suspected carriers of Fabry disease had prolonged conduction velocity but normal distal latency. On the other hand, 8 of 12 males affected with Fabry disease demonstrated slow nerve conduction velocity while 4 of the 8 had prolonged distal latency. Frequently, only one of the two nerves studied showed abnormalities. These abnormalities were not related to patient age. Interfamilial variations in the abnormalities were present.