A cytogenetic survey in Menkes disease: implications for the detection of chromosomal rearrangements in X linked disorders

Menkes disease: underlying genetic defect and new diagnostic possibilities

Cloning of the gene defective in the X-linked neurodegenerative disorder Menkes disease led to a cascade of new findings. Besides giving a better understanding of the intracellular copper homeostasis, these findings had important consequences from a clinical point of view. Today the underlying genetic defect has been described in several patients affected by one of the three hereditary disorders of copper metabolism: Menkes disease, occipital horn syndrome and wilson disease. In this review we discuss mainly Menkes disease and the impact of the recent findings on the diagnosis of this disorder.

Menkes disease: recent advances and new aspects

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Menkes disease: recent advances and new insights into copper metabolism

Copper is a trace element necessary for the normal function of several important enzymes but copper homeostasis is still poorly understood. In recent years remarkable progress has been made in this field following the isolation of the gene defective in Menkes disease. Menkes disease and occipital horn syndrome are X-linked recessive disorders, demonstrating the vital importance of copper, which is also highly toxic in excessive amounts. Its destructive effects are reflected in the autosomal recessive Wilson's disease. Progressive neurodegeneration and connective tissue disturbances are the main manifestations of Menkes disease. Although many patients present a severe clinical course, variable forms can be distinguished, and the occipital horn syndrome has been suggested to be a mild allelic form. The Menkes locus is mapped to Xq13.3 and the gene defective in Menkes disease has been isolated by positional cloning. The gene is predicted to encode an energy-dependent copper-binding protein, the first intracellular copper transporter described in eukaryotes. Isolation of the gene and subsequent characterization of the exon-intron organization now enables the establishment of DNA-based diagnostic methods. Furthermore, identification of the Menkes disease gene led to other important findings, such as isolation of its mouse homologue, confirming the allelic relationship between Menkes disease and occipital horn syndrome, and isolation of the defective genes in Wilson's disease and its rat homologue.

X;1 translocation in a female Menkes patient: characterization by fluorescence in situ hybridization

Menkes disease is an X-linked recessive disorder of copper metabolism, characterized by progressive neurological degeneration, abnormal hair and connective tissue manifestations. We present a female Menkes patient, with classical Menkes features, carrying a de novo balanced translocation 46,X,t(X;1)(q13;q12). The breakpoint on the X chromosome was narrowed down to Xq13.3 within a 1 Mb YAC contig containing the Menkes gene, using fluorescence in situ hybridization. The translocated X chromosome was of paternal origin and non-randomly active leading to the expression of the disease. This was additional evidence for paternal origin of de novo chromosome rearrangements, including all the X; autosomal translocations examined so far.