Familial hypo- -lipoproteinaemia

Current therapeutic strategies for patients with polyneuropathies secondary to inherited metabolic disorders

Supportive care, symptomatic treatment, and patient education should be provided for patients with inherited or acquired polyneuropathies. In addition, specific treatment is available for many of the acquired polyneuropathies. Genetic counseling is valuable for many patients with inherited polyneuropathies, but only rarely is specific treatment an option for these patients. However, specific treatments are available for many of the rare and devastating systemic disorders associated with polyneuropathies. Thus, clinicians must promptly diagnose these inherited disorders so that specific treatment may be initiated. The clinical features of these rare inherited disorders are emphasized.

Amyotrophic choreo-acanthocytosis: a new observation in southern Europe

Amyotrophic choreo-acanthocytosis is a rare disease of adult onset characterized by dyskinesias, neurogenic muscular atrophy, erythrocytary acanthocytosis with normal serum lipoproteins and elevated levels of serum CPK. Presumably, this disorder is an autosomal recessively inherited trait. This disease has been described in Japanese, English, Finnish and Puerto Rican people. This is the first observation in the southern countries of Europe, in two members of a Calabrian family. The authors point out that amyotrophic features can occur several years before the appearance of the extrapyramidal disorders.

A clinical and neurophysiological investigation of a Danish kindred with heterozygous familial hypobetalipoproteinemia

A three-generation transmission of under five percentile values for serum low density lipoprotein and low density lipoprotein cholesterol typical of heterozygous familial hypobetalipoproteinemia was demonstrated in a Danish family. Slight clinical signs of CNS abnormality were found in 4 of the 8 subjects with heterozygous familial hypobetalipoproteinemia, but did not resemble the neurological findings in abetalipoproteinemia nor in the previously described patients with familial hypobetalipoproteinemia. There were no signs of myelin dysfunction in the central nervous system as judged from the normal latency of visual and somatosensory evoked potentials.

Hypobetalipoproteinaemia--a variant of the Bassen-Kornzweig syndrome

A patient is reported with hypobetalipoproteinaemia and clinical features resembling the Bassen-Kornzweig syndrome (abetalipoproteinaemia) more completely than previously described. This supports a link between hypobetalipoproteinaemia and abetalipoproteinaemia and it is suggested that the Bassen-Kornzweig syndrome has a wide spectrum with serum betalipoprotein ranging from absent to normal. It is likely that there are different genetic entities with similar end results.

Hypobetalipoproteinemia with abnormal prebetalipoprotein

A 47-year-old man who had cerebellar ataxia and low plasma lipid and lipoprotein levels is reported. His tendon reflexes were hyperactive and the plantar responses were extensor. There was no acanthocytosis. Total lipids (380 mg/dl), total cholesterol (106 mg/dl), esterified cholesterol (74 mg/dl), triglyceride (58 mg/dl), phospholipids (124 mg/dl) and free fatty acids (303 muequiv./l) were generally decreased. A disturbance of lipid absorption due to a defect of chylomicron formation and hepatic steatosis were also disclosed. On lipoprotein electrophoresis, prebetalipoprotein was very faint and migrated more slowly than normal. Betalipoprotein and alphalipoprotein were moderately reduced in concentration but migrated normally. The concentration of isolated VLDL was only one-tenth of that in normal subjects and it migrated as slow prebetalipoprotein. Although the lipid composition of VLDL was similar to that of normal VLDL, the lack of minor components was disclosed by SDS-PAG electrophoresis. Incorporation of [1-14C]acetate into VLDL lipids was significantly reduced to a greater extent than that of LDL and HDL. From these findings, we discuss the possibility that hypobetalipoproteinemia results from impaired VLDL synthesis.

Atypical retinitis pigmentosa in familial hypobetalipoproteinemia

Of three patients with familial hypobetalipoproteinemia, a 42-yeear-old white woman, who was homozygous for this autosomal dominantly inherited disease, had no detectable serum betalipoprotein and had a marked retinal pigmentary degeneration characterized by ring scotomas by Goldmann perimetry, extinguished electroretinographic responses, delayed responses and elevated thresholds during dark adaptometry, and abnoramal cone thresholds. A 4-year-old daughter and a 28-year-old niece of the first patient, who wer heterozygous, had reduced but detectable levels of serum betalipoprotein and no significant retinal pigmentary degeneration. Unlike patients with autosomal recessively inherited abetalipoproteinemia (the Bassen-Kornzweig syndrome), none of our patients had significant neurologic of cardiac defects. Although the level of serum betalipoprotein might be correlated with retinal pigmentary degeneration in familial hypobetalipoproteinemia and abetalipoproteinemia, it appears that neurologic and cardiac defects are dependent on other factors.