FOXL2 copy number changes in the molecular pathogenesis of BPES: unique cohort of 17 deletions.

Blepharophimosis Syndrome (BPES) is an autosomal dominant developmental disorder of the eyelids with or without ovarian dysfunction caused by FOXL2 mutations. Overall, FOXL2deletions represent 12% of all genetic defects in BPES. Here, we have identified and characterized 16 new and one known FOXL2 deletion combining multiplex ligation-dependent probe amplification (MLPA), custom-made quantitative PCR (qPCR) and/or microarray-based copy number screening. The deletion breakpoints could be localized for 13 out of 17 deletions. The deletion size is highly variable (29.8 kb - 11.5 Mb), indicating absence of a recombination hotspot. Although the heterogeneity of their size and breakpoints is not reflected in the uniform BPES phenotype, there is considerable phenotypic variability regarding associated clinical findings including psychomotor retardation (8/17), microcephaly (6/17), and subtle skeletal features (2/17). In addition, in all females in whom ovarian function could be assessed, FOXL2 deletions proved to be associated with variable degrees of ovarian dysfunction. In conclusion, we present the largest series of BPES patients with FOXL2 deletions and standardized phenotyping reported so far. Our genotype-phenotype data can be useful for providing a prognosis (i.e. occurrence of associated features) in newborns with BPES carrying a FOXL2 deletion.

Euchromatic variant 16p+. Implications in prenatal diagnosis.

BACKGROUND: Euchromatic imbalances at the cytogenetic level are usually associated with phenotypic consequences. Among the exceptions are euchromatic variants of chromosome 16 (16p+) with normal phenotype. There is a growing list of euchromatic duplications and deletions involving both G-positive and G-negative bands that seem to be phenotypically neutral, but these euchromatic variants are rare. OBJECTIVE: The aim of this report is to describe a new familial case of euchromatic variant 16p+ and to emphasise the misinterpretation of these rare euchromatic variants particularly when ascertained at prenatal diagnosis. METHODS AND RESULTS: Fluorescence in situ hybridisation with clone RP11-261A7 showed an amplified signal in the larger chromosome 16. This clone contains FLJ43855 gene, similar to sodium- and chloride-dependent creatine transporter. CONCLUSION: So, this 16p+ variant that involves amplification of pseudogenetic sequences is considered a polymorphism in normal individuals.

MLPA vs multiprobe FISH: comparison of two methods for the screening of subtelomeric rearrangements in 50 patients with idiopathic mental retardation.

Subtelomeric rearrangements not visible by conventional cytogenetic analysis have been reported to occur in approximately 5% of patients with unexplained mental retardation (MR). As the prevalence of MR is high, many patients need to be screened for these chromosomal abnormalities routinely. Multiplex ligation-dependent probe amplification (MLPA) is a new technique for measuring sequence dosage, allowing large number of samples to be processed simultaneously and thus significantly reducing laboratory work. We have assessed its performance for the detection of subtelomeric rearrangements by comparing the results with those of our previous multiprobe fluorescence in situ hybridization (FISH) assay. We have tested 50 patients with idiopathic MR, dysmorphic features, congenital malformations, and/or familial history of MR. Our results show a high degree of concordance between the two techniques for the 50 samples tested. On the basis of these results, we conclude that MLPA is a rapid, accurate, reliable, and cost-effective alternative to FISH for the screening of subtelomeric rearrangements in patients with idiopathic MR.

Comparative study of three diagnostic approaches (FISH, STRs and MLPA) in 30 patients with 22q11.2 deletion syndrome.

The 22q11.2 deletion syndrome is commonly diagnosed using fluorescence in situ hybridization (FISH) with commercial probes. The chromosomal breakpoints and deletion size are subsequently characterized by short tandem repeat (STR) segregation tests or by further FISH probes. Recently, a multiplex ligation-dependent probe amplification (MLPA) single tube assay was developed to detect deletions of the 22q11.2 region and other chromosomal regions associated with DiGeorge/velocardiofacial syndrome. We have compared the results of these three techniques in a group of 30 patients affected with 22q11.2 deletion syndrome. MLPA correctly called all patients who had been previously diagnosed by FISH. The MLPA results were concordant in all patients with the STR analysis in respect to deletion size. Furthermore, this novel technique resolved seven cases that were undetermined by STR analysis. These results confirm the efficiency of MLPA as a rapid, reliable, economical, high-throughput method for the diagnosis of 22q11.2 deletion syndrome.

Tetrasomy 8p: discordance of amniotic fluid and blood karyotypes.

We describe a girl with congenital heart defect (ventricular septal defect), facial, ear and bone anomalies, agenesis of corpus callosum and conventional cytogenetic studies showing tetrasomy 8p. The identity of the isochromosome was confirmed by fluorescent in situ hybridization (FISH) using painting, subtelomeric and alpha satellite probes for chromosome 8. The extra isochromosome was observed in 100% of cultured peripheral lymphocytes (47,XX,+i(8)(p10)), but normal chromosomes were recorded in cultured amniotic fluid. Microsatellites analysis of the patient's DNA with two markers mapping 8p showed three different peaks, and two markers mapping 8q showed two peaks. To the best of our knowledge, this patient represents the twelfth reported case of tetrasomy 8p. In addition, our report is the first case with a pure tetrasomy 8p in blood, (the other published cases are mosaic 8p), and the second case with a discordance of amniotic fluid and blood karyotypes [Robinow et al., 1989: Am J Med Genet 32:320-324].

Autosomal recessive hydrocephalus due to aqueduct stenosis: report of a further family and implications for genetic counselling.

We report on two abortuses with hydrocephalus due to congenital stenosis of the aqueduct of Silvius. The occurrence of this disorder in two siblings (a male and a female) with normal parents supports the autosomal recessive pattern of inheritance. Such a mechanism of inheritance should be taken into account when counselling families with congenital hydrocephaly due to aqueduct stenosis.

Rothmund-Thomson syndrome and Addison disease.

We report an 18-year-old man with the unusual combination of Rothmund-Thomson syndrome (RTS) and Addison disease. He was admitted when he was 26 months old because of short stature, dehydration, metabolic acidosis, hyperpigmentation, and typical skin lesions. Because his growth remained delayed, at age 10 years he was given a trial of recombinant growth hormone. After six years of treatment no improvement in height, bone, or sexual maturation was observed. This fact may be related to a defect in connective tissue metabolism. Chromosomal analysis of peripheral blood lymphocytes revealed increased numbers of breaks and gaps. Fibroblasts cultured from affected skin did not grow. Patients with RTS are prone to developing cancer, but no malignant disease was found in our patient. Early diagnosis and treatment of both endocrinologic and malignant complications are essential for survival of patients with this rare syndrome.

Lethal Pallister-Killian syndrome: phenotypic similarity with Fryns syndrome.

The Pallister-Killian syndrome is a sporadic multiple congenital anomaly syndrome characterized by "coarse" face, profound mental retardation, and epilepsy. Chromosomes of peripheral lymphocytes are usually normal, but tissue cultures show varying degrees of mosaicism for isochromosome 12p. In babies who die neonatally of severe malformations, including diaphragmatic hernia, and who also have a "coarse" face, acral hypoplasia, and other internal anomalies, Fryns syndrome is more likely to be suspected than Pallister-Killian syndrome, especially if karyotyping is unavailable or if peripheral lymphocytes have a normal chromosome constitution. An initial diagnosis of Fryns syndrome had to be modified in 3 successive newborn infants since chromosome analysis or in situ hybridization with a chromosome 12 probe on kidney tissue demonstrated the mosaic aneuploidy characteristic of Pallister-Killian syndrome. These 3 patients confirm that a similar pattern of malformations can be present in both conditions at birth. It consists of "coarse" face, acral hypoplasia, diaphragmatic hernia, and other defects. Newborn infants who present this phenotype, but lack a conclusively normal chromosome test, may not have Fryns syndrome. A diagnosis of Fryns syndrome should be made carefully to avoid the risk of inappropriate genetic counseling.

Fragile X syndrome with extra microchromosome.

A mentally retarded male with Martin-Bell syndrome, who has an extra microchromosome and is fra X negative in cytogenetic study is reported. Because of its small size, the origin of the microchromosome could not be determined. Two other affected males in this family (a cousin and a nephew of the proband) were fragile X positive, 24% and 26%, respectively. Cytogenetic studies and DNA analysis with the probe St B 12.3 were performed on several members of the family. The proband and the two other affected males showed a similar full mutation on the molecular study. This study emphasizes the importance of molecular analysis in the diagnosis of fragile X syndrome, particularly when cytogenetic studies demonstrate fra X negative in individuals in families likely to have X-linked mental retardation.

De novo t(5p;21q) in a patient previously diagnosed as monosomy 21.

In situ hybridization was used to characterize an undetected chromosome translocation in a child whose metaphase chromosome analysis in peripheral blood and in skin culture revealed apparent monosomy 21. The cytogenetic study revealed 45 chromosomes, and no other structural anomalies were detected with G banding. In situ hybridization of chromosome 21-specific probes to metaphase chromosomes and reverse banding from the proband showed a de novo translocation between chromosome 5 and chromosome 21.

A malformed child with a recombinant chromosome 7, rec(7) dup p, derived from a maternal pericentric inversion inv(7)(p15q36).

We report a child with facial dysmorphic features, hypoplasia of the external genitalia, intestinal malrotation, congenital cardiac defect, and minor limb anomalies. Chromosome studies showed a recombinant chromosome 7, rec(7) dup p, resulting from a maternal pericentric inversion inv(7)(p15 q36). Thus, this child had partial trisomy 7p in addition to a small distal monosomy 7. The clinical findings are compared with those found in previous reports of trisomy 7p. Finally, some general principles for genetic counselling are discussed.

Tetraploidy in a liveborn infant.

We report a 3 month old boy with tetraploidy, found in peripheral blood and skin fibroblast cultures, with severely delayed growth and neurodevelopment, and with a cleft lip; these findings have not been described before. This report brings to seven the total number of liveborn infants with a 92,XXYY karyotype.

Trisomy 13 syndrome and neural tube defects.

Abnormalities of the CNS, such as arhinencephaly or holoprosencephaly, are common findings in trisomy 13 syndrome. However, neural tube defects (NTDs) are rarely reported. A review of 267 patients in the literature on reported CNS developmental defects in trisomy 13 syndrome showed only 6 patients with lumbosacral NTDs. No case of encephalocele or anencephaly was found. We report on 3 patients with spina bifida from the records of 34 necropsies of karyotyped trisomy 13 syndrome, which were found among 403,710 births.

Balanced reciprocal translocation (X;20) limited to Wilms' tumor in a Wiedemann-Beckwith syndrome.

A girl aged 4 years 3 months with sporadic unilateral Wilms' tumor associated with Wiedemann-Beckwith syndrome, but without aniridia, was found to have a t(X;20) in the tumor cells. Karyotypes of peripheral blood of the patient and her parents were normal. This translocation was confined to the tumor and not been previously reported either in nephroblastoma or any other neoplastic processes. Although there is no microscopic deletion on chromosome 11 and catalase activity was not decreased, we cannot rule out the possibility of a point mutation or a submicroscopic deletion.

The 18p- syndrome. Report of five cases.

Five children, three males and two females were found to have a short arm deletion of chromosome 18. Four of them display some of the typical features of this syndrome: microcephaly, round face, hypertelorism, broad-based nose, "carp-mouth", microrethrognathia, pterygium colli, dysplastic and low set ears, clinodactily, failure to grow, muscular hypotony and mental retardation. Different hypotheses are discussed in order to explain the variable phenotypical expression of the 18 p-syndrome.

Trisomy 20p from maternal translocation and anencephaly. Case report and genetic review.

This paper concerns the case of an anencephalus male fetus with partial trisomy 20p product of a maternal translocation 46,XX, t(15;20) (p11.2;p12), ascertained by prenatal diagnosis. A cytogenetic review of previous cases is presented. Several hypotheses are discussed in order to explain the recurrent abortions of the mother and the aetiology of anencephaly in this last pregnancy.

[Partial trisomy 18q]. / Trisomía parcial 18q.

Authors present a new case with partial trisomy for long arms of chromosome 18(q12-qter) resulting from a balanced translocation t(4;18) on her mother. Comparing clinical features of our patient with that of other reported cases with the same trisomic segment, we can deduce that most important characteristics on this syndrome are: psychomotor and grow retardation, congenital heart disease, dolicocephaly, low set and malformed ears, micrognathia, short neck with redundant skin and a longer survival than in total trisomy 18.

[Trisomy 5p: a report of 2 cases]. / Trisomía 5p: aportación de dos casos.

Authors report two patients from different families who present similar abnormalities caused by an "almost complete" trisomy of the short arm of chromosome 5 [case No. 1: 46, XY, der (20), t (5; 20) (p11;p13), mat; case No.2: 46, XY, dup (5p)]. Several family members of case No. 1 were balanced translocation carriers. Case No. 2 is probably due to de novo duplication. Clinical findings in our cases and those cited in the literature allow identification of certain main features characteristic of "almost complete" trisomy 5p: hypotonia, weak cry, mongoloid slant of eyes, epicanthus, depressed nasal bridge, auricular anomalies, bilateral cryptorchidism and, less frequently, macrocephaly, micrognathia and club feet.