Molecular cytogenetic analysis of a duplication Xp in a female with an abnormal phenotype and random X inactivation.

We describe a female infant with severe abnormal phenotype with a de novo partial duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) was performed with YAC probes, further delineating the breakpoints. The karyotype was 46, X dup(X)(p11-p21.2). Cytogenetic replication studies showed that the normal and duplicated X chromosomes were randomly inactivated in lymphocytes. In most females with structurally abnormal X chromosomes, the abnormal chromosome is inactivated and they are phenotypically apparently normal relatives of phenotypically abnormal males having dupX. Therefore, in this case, there is functional disomy of Xp11-p21.2 in the cells with an active dup(X), most likely resulting in abnormal clinical findings in the patient.

[Neonatal hyperparathyroidism secondary to unknown maternal hypoparathyroidism]. / Hyperparathyroïdie néonatale secondaire à une hypoparathyroïdie maternelle méconnue.

UNLABELLED: Vitamin D or its analogue (calcitriol) is an effective treatment for hypoparathyroidism during pregnancy. Normal babies are delivered and very few cases of associated neonatal hyperparathyroidism are reported. CASE REPORT: We report the case of a baby born to a mother suffering unknown hypoparathyroidism. He was delivered prematurely by cesarean section for birth asphyxia. His mother had had recurrent bouts of impetigo herpetiformis for several months. Severe demineralization associated with decreased plasma calcium level were observed at birth. The PTH level was very high (955 ng/mL) in the baby and very low in the mother, leading to the diagnosis. The baby was given intravenous calcium gluconate, oral 1 alpha-hydroxyvitamin D and mechanical ventilation. Normal plasma calcium level was reached on day 2. PTH level improved by one month of age. Because of impaired respiratory mechanics and bronchopulmonary dysplasia, the baby was kept on ventilation for 58 days. By 20 months of age, he was in good health despite a small height for his age. CONCLUSION: In such cases 1 alpha-hydroxyvitamin D seems to be very effective but plasma and urinary calcium levels need careful monitoring.