Methylation mosaicism of 5'-(CGG)(n)-3' repeats in fragile X, premutation and normal individuals.

Fragile X syndrome (FRAXA) is characterized at the molecular level by an expansion of a naturally occurring 5'-(CGG)(n)-3' repeat in the promoter and 5'-untranslated region (5'-UTR) of the fragile X mental retardation (FMR1) gene on human chromosome Xq27.3. When expanded, this region is usually hypermethylated. Inactivation of the FMR1 promoter and absence of the FMR1 protein are the likely cause of the syndrome. By using the bisulfite protocol of the genomic sequencing method, we have determined the methylation patterns in this region on single chromosomes of healthy individuals and of selected premutation carriers and FRAXA patients. In control experiments with unmethylated or M- Sss I-premethylated DNAs, this protocol has been ascertained to reliably detect all cytidines or 5-methylcytidines as unmethylated or methylated nucleotides, respectively. Analyses of the DNA from FRAXA patients reveal considerable variability in the lengths of the 5'-(CGG)(n)-3' repeats and in the levels of methylation in the repeat and the 5'-UTR. In one patient (OEl) with high repeat length hetero-geneity ( n = 15 to >200), shorter repeats (n = 20-80) were methylated or unmethylated, longer repeats ( n = 100-150) were often completely methylated, but one repeat with n = 160 proved to be completely unmethylated. This type of methylation mosaicism was observed in several FRAXA patients. In healthy females, methylated 5'-CG-3' sequences were found in some repeats and 5'-UTRs, as expected for the sequences from one of the X chromosomes. The natural FMR1 promoter is methylation sensitive, as demonstrated by the loss of activity in transfection experiments using the unmethylated or M- Sss I-premethylated FMR1 promoter fused to the luciferase gene as an activity indicator.

Effect of the size of the deletion and clinical manifestation in Wolf-Hirschhorn syndrome: analysis of 13 patients with a de novo deletion.

We performed clinical, cytogenetic, and molecular analyses on 13 patients (8 females and 5 males, aged 6 months to 13 years) with Wolf-Hirschhorn syndrome due to de novo deletions of chromosome 4p. All patients presented with the typical facial gestalt, microcephaly, and profound mental retardation. Other clinical signs were low birth weight (10/13; 77%), postnatal short stature (8/12; 66%), muscular hypotonia (12/13; 92%), seizures (11/13; 85%), congenital heart defects (4/13; 31%), colobomata of iris (4/12; 33%), genital anomalies (4/13; 31%), deafness (3/13; 23%), and renal anomalies (3/13; 23%). The smallest deletion was a submicroscopic terminal deletion of nearly 2.5 Mb. The largest was a terminal deletion of nearly 30 Mb. Cleft lip/palate, preauricular pits/tags, and congenital heart defects were present only in patients with terminal deletions larger than 10 Mb. The deviations from mean birth weight, birth length, and postnatal head circumference correlated with the size of the deletion. Determining the parental origin of the deletion with microsatellite markers, the maternal allele was missing in three patients and the paternal allele in eight patients. Our observations support the existence of a partial genotype-phenotype correlation in Wolf-Hirschhorn syndrome.

FISH studies in 45 patients with Rubinstein-Taybi syndrome: deletions associated with polysplenia, hypoplastic left heart and death in infancy.

Rubinstein-Taybi syndrome (RTS) is a dominant Mendelian disorder characterised by mental retardation, a typical facies, broad thumbs and short stature. Previous reports indicated that 4-25% of RTS patients have a submicroscopic 16p13.3 deletion of the CBP gene. Using FISH and cosmid probes RT100, RT191 and RT203 we studied 45 RTS patients from Germany, the Czech Republic, Austria and Turkey and found four deletions (8.9%, pooled data including other studies: 11%). All deletions were interstitial; three spanned the CBP gene (RT100-RT203) and one was smaller (RT100 only). Previous studies reported no phenotype-genotype correlation between RTS patients with or without a deletion. Our findings suggest a more severe phenotype. The mean age at presentation was 0.96 years in patients with a deletion as against 11.12 years in those without. Patients A and B with a deletion died in infancy which is rare in RTS and was not observed among the other patients. Patients A and D had accessory spleens, Patient A with hypoplastic left heart, abnormal pulmonary lobulation and renal agenesis. This is the second report of hypoplastic left heart and the first report of polysplenia with RTS. The signs suggest a developmental field defect (disturbance of laterality) either as a newly recognised pattern of RTS, or alternatively a novel contiguous gene syndrome.

Lenz-Majewski hyperostotic dwarfism: reexamination of the original patient.

In 1974, Lenz and Majewski gave a short description of a 2-year-old girl with generalized hyperostosis, proximal symphalangism, syndactyly, brachydactyly, cutis laxa, mental retardation, marked hypertelorism, and enamel hypoplasia. This disorder was later named Lenz-Majewski hyperostotic dwarfism. We describe the reexamination of the original patient at the age of 30 years.

Rectal atresia as rare manifestation in EEC syndrome.

A newborn boy presented with bilateral split hand/foot malformation, sparse hair, dry and scaly skin, and nasolacrimal duct obstruction. Despite absence of cleft lip or palate, the findings fit the EEC syndrome. Additionally, the boy had rectal atresia. At least six further patients with EEC syndrome and anal atresia (two published, four unpublished) demonstrate, that anorectal malformation is a further, but rare anomaly in EEC syndrome.

Bilateral complete polysyndactyly (type IV Haas).

We describe complete cutaneous syndactyly of all fingers and polydactyly in a 2-month-old girl. Based on 3 previous reports, this constitutes a separate entity (McKusick 18620) with probable autosomal dominant inheritance.

Alopecia, macular degeneration, and growth retardation: a new syndrome?

A syndrome with growth retardation, repeated hair loss, and ring-shaped degeneration of the retinal pigmentary epithelium is described. Similarities to a known syndrome could not be found.

Studies of microcephalic primordial dwarfism II: the osteodysplastic type II of primordial dwarfism.

We describe three unrelated patients with intrauterine growth retardation (IUGR) and nearly identical bone changes. In certain respects, they share similarities with the Seckel syndrome: small forehead, moderately prominent nose, micrognathia, pronounced intrauterine and postnatal growth retardation, microcephaly, and mental retardation. Differences from the Seckel syndrome include disproportionate shortness of forearms and legs in the first years of life, brachymesophalangy, brachymetacarpy I, V-shaped flare of at least the distal femoral metaphyses, triangular shape of the distal femoral epiphyses, a high and narrow pelvis, proximal femoral epiphysiolysis, and coxa vara. Hormone studies in two cases demonstrated no gross disturbances, especially no deficit of hGH and somatomedin. Two previously reported cases referred to as Seckel syndrome had nearly identical bone changes. The cause of this "new" type of IUGR remains unclear.

Microcephalic osteodysplastic primordial dwarfism type II: report of three cases and review.

We report on three further patients with microcephalic osteodysplastic dwarfism type II. All children have marked intrauterine and postnatal growth failure, microcephaly, and mental and statomotor retardation. They are disproportionately short statured due to short limbs. Characteristic skeletal abnormalities are small iliac wings with flat acetabular angles, coxa vara, V-shaped distal femoral metaphyses, and triangular distal femoral epiphyses, as well as pseudoepiphyses of metacarpals, short first metacarpals, and brachymesophalangy V. At age 3 years, bilateral epiphyseolysis of the femoral heads occurred in case 1. Including our patients, 17 cases have been published so far. We review the clinical picture and the cause.

Congenital scalp defects with distal limb anomalies (Adams-Oliver syndrome): report of ten cases and review of the literature.

We describe one family with 5 affected persons in 4 generations, another family with 2 affected brothers and 3 sporadic cases of the rare syndrome of congenital scalp defects with distal limb deficiency. The manifestations of this syndrome are highly variable. Review of the literature showed 11 families and 19 sporadic cases. In most families the disorder clearly follows an autosomal dominant pattern of inheritance, but in some families with reduced penetrance. Important differential diagnoses are the syndrome of scalp defect and postaxial polydactyly, the syndrome of scalp defect and split-hand defect, amniotic band sequence, and epidermolysis bullosa dystrophica type Bart.

Acrofacial dysostosis of unknown type: nosology of the acrofacial dysostoses.

We describe a stillborn girl with an unclassified form of mandibulofacial dysostosis, a postaxial defect of the right, and a preaxial defect of the left hand. The Nager syndrome is characterized by preaxial limb defects, whereas the Genée-Wiedemann syndrome (= Miller syndrome) by postaxial limb defects. We briefly review the established acrofacial dysostoses (AFD) and discuss the position of our case in the current classification.

Familial arhinia, choanal atresia, and microphthalmia.

We describe two females (aunt and niece) with variable manifestations of arhinia, choanal atresia, microphthalmia, and hypertelorism. In the literature there is only one report on this syndrome in sibs. We hypothesize autosomal dominant inheritance with reduced penetrance.

The genetics of Crohn disease: complex segregation analysis of a family study with 265 patients with Crohn disease and 5,387 relatives.

We have analysed the pedigrees of 265 probands with Crohn disease, collected from a specialty clinic at the University of Düsseldorf. Complex segregation analysis suggests the presence of a recessive gene with incomplete penetrance for susceptibility to the disease with no residual causes of family resemblance. However, a proportion of the isolated cases are probably due to phenocopies, this proportion being greatest among cases with an advanced age of onset.

Blepharo-cheilo-dontic (BCD) syndrome.

Patients with the autosomal dominant ble-pharo-cheilo-dontic (BCD) syndrome have ectropion of lower eyelids, distichiasis of upper eyelids, euryblepharon, bilaterally cleft lip/palate, oligodontia, and conical crown form. Initially known under the eponym "Elschnig syndrome" (1912), BCD syndrome has been described in binary, ternary, and quaternary combination. There is overlap with the syndrome reported by Martínez et al. [1987], postaxial acrofacial dysostosis (Miller syndrome, Genée-Wiedemann syndrome), and a syndrome reported briefly by Warburg.

Alcohol embryo- and fetopathy. Neuropathology of 3 children and 3 fetuses.

Maternal chronic ethanol abuse during pregnancy causes malformations of the offspring. Three children (aged 6 months, 9 months, 4 1/2 years) and 3 fetuses (17th, 18th, and 20th gestational week) showed a wide spectrum of disorders ranging from severe dysraphic state, arhinencephaly, porencephaly, agenesis of corpus callosum, a range from hydranencephaly to microdysplasias (p.e. reduced gyration of dentate nucleus and inferior olives), and a range from gastrochisis or congenital heart defects to craniofacial dysmorphogenesis and palmar crease anomalies. The patterns of the cerebral malformations were not as uniform as the clinical phenotype of the alcohol embryopathy. The observations did not support the assumption that there exists a specific period for alcohol teratogenicity.

Pallister-Killian syndrome in older children and adolescents.

The Pallister-Killian syndrome is caused by a mosaic tetrasomy of the short arm of chromosome 12. Although analysis of peripheral blood lymphocytes usually reveals a normal karyotype, an isochromosome 12p mosaicism is detectable in fibroblast cultures; therefore, in this rare chromosomal aberration, clinical recognition is crucial for appropriate cytogenetic investigations. The phenotype of younger children has already been well documented. During childhood and adolescence, however, the phenotype changes markedly. The disorder in older children and young adults is characterized by a coarse and flat facies, macroglossia prognathia, everted lower lip, and severe psychomotor retardation with muscular hypertonia and contractures. Two severely mentally retarded patients are reported whose diagnoses were confirmed by fibroblast cultures at ages 16 and 21 years.

One novel and two recurrent missense DKC1 mutations in patients with dyskeratosis congenita (DKC).

X-linked dyskeratosis congenita (DKC) is a progressive multisystem disorder most severely affecting tissues with a high cellular turnover such as skin, mucous membranes, and blood. Most patients die of bone marrow failure, although the chances of succumbing to various types of cancer and pulmonary disease are also high. DKC is caused predominantly by missense mutations in the DKC1 gene linked to Xq28. Some of the clinical features are reminiscent of premature ageing and this agrees with recent indications that DKC could be a telomere maintenance disorder. There is considerable variability in the type, severity, and age at onset of the various anomalies. Recognition of this has increased with the finding that patients with Hoyeraal-Hreidarsson syndrome (HHS) who exhibit severe neurological problems in addition to early-onset pancytopenia, also bear mutations in the DKC1 gene. For these reasons, and compounded by the range of mutations, phenotype-genotype correlations and accurate assessments of prognosis have not been possible. To complement the present data, we here report on three new cases of DKC and their mutations. One is a novel mutation in the exon 3 (K43E). The other two represent a frequently recurring mutation in exon 11 (A353V) and a less frequently recurring mutation in the exon 3 (T49M).

Osteosarcoma in a 16-year-old boy with Baller-Gerold syndrome.

We report a 16-year-old growth deficient boy with craniosynostosis, radial hypoplasia and hypoplastic thumbs. These findings are consistent with the autosomal recessively inherited Baller-Gerold syndrome (BGS) which furthermore shows a great variability of concomitant occasional anomalies. At the age of 16 years our patient suffered from an osteosarcoma of the left distal femur. The occurrence of malignancies has not yet been reported in the hitherto described 22 patients with BGS.