Search

Ring chromosomes are rare abnormalities caused by the fusion of the telomeric regions. Three-ring chromosome syndromes (Cr 20, Cr 17 and Cr 14) cause epilepsy with variable phenotypes. In ring 17 patients with mild phenotype, some authors have shown an epilepsy syndrome similar to that of ring 20. We report the first case of a girl with ring chromosome 17 and a normal neurological and general cognitive profile. She had had, from 9 years old, focal pharmacoresistant epilepsy associated with episodes of non-convulsive status epilepticus with mainly autonomic features. Cytogenetic analysis revealed an abnormal karyotype characterised by the presence of de novo ring chromosome 17 in 19% of metaphases. The array CGH (100 KB) did not show any genetic deletion. The clinical and epilepsy phenotype was, to a certain degree, similar to that of ring 20 syndrome.

Mucopolysaccharidosis type VI (MPS VI, Maroteaux-Lamy syndrome) is an autosomal recessive disorder caused by the deficit of the arylsulfatase B (ARSB) enzyme, which leads to dermatan sulfate pathological storage, resulting in a wide spectrum of clinical phenotypes. To date more than 130 different mutations were reported, most of them being restricted to individual families. We here report the first study on the ARSB gene mutations in MPS VI patients of Turkish ethnogeographic origin. On the whole we analyzed 13 unrelated families recruited from 3 different Turkish clinical centers, for a total of 52 subjects, including patients, parents, and siblings. The molecular characterization of ARSB gene in these subjects lead to the identification of eight different mutations (6 missense mutations and two single-nucleotide deletions) one of which novel: c.532C>G (p.H178D). We characterized seven different genotypes, all homozygous except one. The analysis highlighted c.962T>C (p.L321P) as the most frequently detected mutation in the group of patients examined and the c.1072G>A (p.V358M) as the most frequent polymorphism. All parents and 50% of the healthy siblings analyzed carried in a heterozygous condition the mutation identified in the affected relative. The high number of homozygotes reported in this study reflects the high degree of consanguinity of the Turkish population, being the parents of most of the patients here examined, first-degree cousins. As consanguineous marriages are an integral part of the Turkish society, carriers identification accompanied by genetic counseling in families at risk is the eligible approach to minimize the effects of consanguinity in this population.

Objective: We surveyed the datasheets of 29 laboratories concerning prenatal diagnosis of de novo apparently balanced chromosome rearrangements to assess the involvement of specific chromosomes, the breakpoints distribution and the impact on the pregnancy outcome., Method: By means of a questionnaire, data on 269.371 analyses performed from 1983 to 2006 on amniotic fluid, chorionic villus and fetal blood samples were collected., Results: A total of 246 balanced anomalies were detected at frequencies of 72% for reciprocal translocations, 18% for Robertsonian translocations, 7% for inversions and 3% for complex chromosome rearrangements. The total frequencies of balanced rearrangements were 0.09%, 0.08% and 0.05% on amniotic fluid, chorionic villus and fetal blood samples., Conclusion: A preferential involvement of chromosomes 22, 7, 21, 3, 9 and 11 and a less involvement of chromosomes X, 19, 12, 6 and 1 was observed. A nonrandom distribution of the breakpoints across chromosomes was noticed. Association in the location of recurrent breakpoints and fragile sites was observed for chromosomes 11, 7, 10 and 22, while it was not recorded for chromosome 3. The rate of pregnancy termination was about 20%, with frequencies decreasing from complex chromosomal rearrangements (33%), reciprocal translocations (24%) to inversions (11%) and Robertsonian translocations (3%).

We report a case of nuchal cystic hygroma with spontaneous resolution detected by ultrasound examination at 13 weeks' gestation. Fetal karyotype and amniotic fluid alpha-fetoprotein levels were normal. Extreme caution in evaluating this situation is stressed.