Clinical characteristics of myotonic dystrophy type 1 patients with small CTG expansions.

The authors report a genotype-phenotype correlation study in 102 patients with myotonic dystrophy type 1 carrying small CTG repeat expansions. Most patients carrying 50 to 99 CTG repeats were asymptomatic, except for cataracts. Myotonia, weakness, excessive daytime sleepiness, and myotonic discharges at EMG were significantly more present in the patients with 100 to 200 CTG repeats.

Oral loading of homogentisic acid in controls and in obligate heterozygotes for hereditary tyrosinemia type I.

Homogentisic acid (HGA) (50 mg/kg) was given orally to 22 obligate heterozygotes for hereditary tyrosinemia type 1 (HT) and to 11 controls. After 1 h the mean +/- standard error (SE) plasma level of HGA was 30.42 +/- 1.

Different molecular basis for fumarylacetoacetate hydrolase deficiency in the two clinical forms of hereditary tyrosinemia (type I).

Hereditary tyrosinemia is characterized by a deficiency of the enzyme fumarylacetoacetate hydrolase (FAH; E.C.3.

Myotonic dystrophy: linkage with apolipoprotein E and estimation of the gene carrier status with genetic markers.

The genes for myotonic dystrophy (MD) and for apolipoprotein E (ApoE) belong to a chromosome 19 synthenic group of markers. A familial linkage analysis between MD and ApoE was performed using the J Ott LIPED program (IBM PC/XT, April 1984) to estimate the genetic distance between these 2 genes. Of a total of 136 individuals in 11 MD families, 81 were confirmed to be affected by the disease and 41 were asymptomatic.

Characterization of a reverse transcriptase activity associated with retrovirus-like particles in a Drosophila cell line.

The properties of an endogenous RNA-dependent DNA polymerase (reverse transcriptase) associated with retrovirus-like particles (VLP) in a Drosophila melanogaster cell line were characterized. The enzyme requires a monovalent and a divalent cation, a sulfhydril-reducing agent and the four deoxynucleosides triphosphates for a maximal activity. The reaction was enhanced by a detergent and was sensitive to a DNA-A-free RNA-A indicating that the enzymatic activity was indeed associated with VLP which contain intrinsic RNA.