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Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disorder characterised by progressive spasticity of the lower limbs. Beside ‘pure’ forms of HSP, ‘complicated’ forms are reported, where spasticity occurs associated with additional symptoms. We recently described an Italian family with a complicated dominant form of HSP (SPG9) and we mapped the gene responsible to 10q23.3–q24.2, in a 12 cM interval between markers D10S564 and D10S603. The phenotypic manifestations in our family are reminiscent of those already described in a smaller British pedigree. We typed individuals from this British family using markers located in the SPG9 critical interval and haplotype reconstruction showed the disorder co-segregating with SPG9. To characterise the SPG9 region better, we constructed a contig of 22 YACs, assigned it to 18 polymorphic markers and positioned 54 ESTs. Furthermore, we searched for ESTs containing a trinucleotide repeat sequence, since anticipation of symptoms was reported in both families. Finally, analysis of a muscle biopsy specimen from one patient was normal, suggesting that, contrary to SPG7, mitochondrial disturbance could not be a primary feature of SPG9.

SummaryWe have recently observed a large pedigree with a new rare autosomal dominant spastic paraparesis. In three subsequent generations, 13 affected individuals presented with bilateral cataracts, gastroesophageal reflux with persistent vomiting, and spastic paraparesis with amyotrophy. Bilateral cataracts occurred in all affected individuals, with the exception of one patient who presented with a chorioretinal dystrophy, whereas clinical signs of spastic paraparesis showed a variable expressivity. Using a genomewide mapping approach, we mapped the disorder to the long arm of chromosome 10 on band q23.3-q24.2, in a 12-cM chromosomal region where additional neurologic disorders have been localized. The spectrum of phenotypic manifestations in this family is reminiscent of a smaller pedigree, reported recently, confirming the possibility of a new syndrome. Finally, the anticipation of symptoms suggests that an unstable trinucleotide repeat may be responsible for the condition.

Roberts syndrome is a rare autosomal recessive condition characterized by growth retardation, cranio-facial abnormalities and symmetrical limb reduction of variable severity. Most patients with Roberts syndrome show a typical cytogenetic finding known as "Roberts syndrome effect". We describe a 4-month-old patient with a mild form of this syndrome, who presented with an asymmetrical reduction of the right upper limb.

We report a female patient with a 46,XX,der(8)t(1;8)(q42.1;p23.3) karyotype who had a mild phenotype characterised by a few subtle dysmorphic features and mild developmental retardation, probably resulting from trisomy 1q42-->qter. The deletion on the short arm of the chromosome 8 appeared to be confined to the distal chromosomal segment.

The bovine CaCC protein is a putative Ca2+-dependent Cl- channel of airway epithelial cells. Therefore, CaCC proteins could contribute to transepithelial Cl- transport and accordingly modify the phenotype of cystic fibrosis (CF) patients. We have identified a murine EST containing a full-length cDNA coding for a 902-amino-acid protein highly homologous to bovine CaCC. The murine gene (mCaCC) maps to chromosome 3 at the H2-H3 band and is expressed, as indicated by Northern blot analysis, in mouse skin and kidney but not in brain, heart, lung or testis. RT-PCR indicates a low expression in tracheal epithelial cells. Heterologous expression of mCaCC in Xenopus oocytes elicits membrane currents that are anion-selective and inhibited by DIDS and by niflumic acid, a blocker of the endogenous chloride current in oocytes. The identification of genes belonging to the CaCC family will help to evaluate their role as ion channels or channel regulators and their actual contribution to epithelial chloride transport.

A centric fission of chromosome 9 was found in a boy with trisomy 9p resulting from a de novo del (9p) and a 9p isochromosome. The patient presented with clinical findings similar to those described in previously reported cases of trisomy 9p. The cytogenetic evaluation and the molecular analysis using fluorescence in situ hybridization (FISH) with specific alphoid probe for chromosome 9 showed a karyotype of 47,XY,+del(9)(q10),+i(9p). We suggest that the mechanism leading to this situation is unusual.