Experience with first trimester prenatal diagnosis of Menkes disease

Expression and Localization of Cellular Prion and COMMD1 Proteins in Human Placenta throughout Pregnancy

Copper is an essential trace element for successful pregnancy. However, the mechanisms by which copper is transported from maternal circulation to the fetus have not been clearly elucidated. Two proteins, cellular prion (PrP(C)) and COMMD1, are known to be responsible for prion diseases and canine copper toxicosis, respectively, and are thought to play a role in copper homeostasis. However, their placental expression and localization throughout human gestation are still unknown. In this study, we used quantitative RT-PCR, western blotting and immunohistochemistry to investigate in detail the expression and localization of PrP(C) and COMMD1 proteins in human placenta throughout pregnancy. Our results show that both proteins are expressed in human placenta. PrP(C) showed the highest mRNA and protein expression levels during the first trimester of pregnancy. PrP(C) and COMMD1 proteins are similarly localized within the placental villi. Both proteins are present in the syncytiotrophoblast, the cytotrophoblast, vascular endothelial cells and Hofbauer cells. These data offer some insights into possible roles for PrP(C) and COMMD1 within the placenta.

Menkes disease: an X-linked neurological disorder of the copper metabolism

Menkes disease is an X-linked, recessive disturbance of copper metabolism associated with a progressive clinical course and abnormal hair. The disease is dominated by neurological symptoms combined with connective tissue manifestations, most of which can be explained by the lack of important copper enzymes. Despite excessive accumulation of the metal in various tissues, a functional copper deficiency is evident, probably caused by a defective intracellular copper transport protein of unknown nature. The molecular basis of the copper disturbance has proven difficult to define and will most likely have to await cloning of the gene. The chromosomal region of interest has now been narrowed down to a sub-band on the long arm of the chromosome (Xq13.3), and positional cloning is in progress in a number of laboratories including our own. Identification of the Menkes gene will be of importance for our understanding of the cellular handling of copper and other trace elements.

Clinical expression of Menkes syndrome in females

Three female patients with Menkes syndrome are described. Clinically, they have typical Menkes syndrome. Biochemically, they have significantly increased 64Cu-uptake in cultured fibroblasts. The chromosomal analysis was normal for two of the patients and abnormal for one patient (45X/46XX mosaicism).

First-trimester diagnosis of Menkes disease: intermediate copper values in chorionic villi from three affected male fetuses

Chorionic villus samples with copper contents of 1.91, 4.2, 5.6, and 6.3 ng/mg were observed in four cases with male karyotypes. These values were outside the range for unaffected males (0.30-0.85 ng/mg), and three of them were outside the control range (0.20-2.39 ng/mg). But these three values were below the values previously observed for affected Menkes fetuses (12.0-24.8 ng/mg). Follow-up by 64Cu uptake studies on the amniotic fluid cells was performed in three of these cases. A combination of 64Cu uptake and chase experiments on the amniotic fluid cells showed more convincingly than 64Cu uptake per se the direct copper values of 4.2 and 5.6 ng/mg to correspond to affected fetuses. Amniotic fluid cells from the male fetus with the CV copper value of 1.9 ng/mg showed normal results. The CV copper value of 6.3 ng/mg was considered pathognomonic for Menkes disease. The pregnancy was terminated, and the diagnosis was confirmed on fetal fibroblasts. Maternal deciduum prepared from the placentae showed in one of the cases with an affected fetus copper values ranging from 1.5 to 5.7 ng/mg. In six additional diagnostic cases, the copper content was determined in both CV samples and maternal deciduum. In three of these cases with normal CV sample copper, maternal decidua values of 4.85-7.8 ng/mg copper were observed. These results show that maternal deciduum contamination of a CV sample could cause a false-positive diagnosis.

Prenatal and postnatal diagnosis of Menkes disease, an inherited disorder of copper metabolism

105 patients with Menkes disease have been diagnosed from 64Cu-uptake studies in fibroblasts. These results are presented together with chase results following removal of 64Cu from the medium for 16 Menkes patients. Second-trimester prenatal diagnosis has been performed in 80 pregnancies with male karyotype. These 64Cu-uptake results show some overlap between the upper end of the normal range and the lower end of the Menkes range. Results are presented to show that a combination of 64Cu-uptake and chase results offers a better diagnostic potential than 64Cu-uptake per se. Chorionic villus copper values from 53 first-trimester prenatal diagnoses are presented. Maternal deciduum from some of these pregnancies contain similar high amounts of copper as found in the chorionic villus samples from affected fetuses. 64Cu-uptake in cultured chorionic villi from affected fetuses and unaffected fetuses is not discriminatory. Chase results seem however to offer a better diagnostic potential.

Postmortem Menkes diagnosis from carrier testing of female relatives

A boy who died at 6 months of age was noted to have sparse, stubby and light hair, pili torti were observed microscopically, and his skin was dry and redundant. As a suspicion of Menkes disease was first raised after his death, serum copper and ceruloplasmin in serum were not measured. Unfortunately, no fibroblasts were available - only fixed and paraffin-embedded samples of brain, spleen and liver. The copper contents of the brain and the liver were lower than in an age-matched control. Fibroblast cultures from the mother, the maternal grandmother, and a maternal aunt of the index patient were analysed for 64Cu-uptake. All these females showed the uptake values expected for Menkes carriers, thus supporting the clinical suspicion of Menkes disease in the index patient. From the above-mentioned results it was highly likely that the index patient had suffered from Menkes disease. Adequate genetic counseling could thus be offered to the family, and in the next pregnancy a first trimester prenatal diagnosis was performed.