The importance of genetic susceptibility in Dupuytren's disease

Dupuytren's disease (DD) is a progressive fibromatosis that causes the formation of nodules and cords in the palmar aponeurosis leading to flexion contracture of affected fingers. The etiopathogenesis is multifactorial with a strong genetic predisposition. It is the most frequent genetic disorder of connective tissues. We have collected clinical data from 736 unrelated individuals with DD who underwent surgical treatment from Germany and Switzerland. We evaluated a standardised questionnaire, assessed the importance of different risk factors and compared subgroups with and without positive family history. We found that family history clearly had the strongest influence on the age at first surgery compared to environmental factors, followed by male sex. Participants with a positive family history were on average 55.9 years of age at the first surgical intervention, 5.2 years younger than probands without known family history (p = 6.7 × 10(-8) ). The percentage of familial cases decreased with age of onset from 55% in the 40-49 years old to 17% at age 80 years or older. Further risk factors analysed were cigarettes, alcohol, diabetes, hypertension, and epilepsy. Our data pinpoint the importance of genetic susceptibility for DD, which has long been underestimated.

Macrocephaly, obesity, mental (intellectual) disability, and ocular abnormalities: alternative definition and further delineation of MOMO syndrome

MOMO syndrome, previously defined as Macrosomia, Obesity, Macrocephaly, and Ocular abnormalities (OMIM 157980) is a rare intellectual disability syndrome of unknown cause. We describe two further patients with MOMO syndrome. Reported data of patients with MOMO syndrome and our own findings indicate that overgrowth does not appear to be a specific feature. We propose to form the acronym "MOMO" from Macrocephaly, Obesity, Mental (intellectual) disability, and Ocular abnormalities, excluding macrosomia from the syndrome name. The combination of obesity, macrocephaly, and colobomas is unique, therefore these features can be used as major diagnostic criteria of MOMO syndrome.

Hallermann-Streiff Syndrome: No Evidence for a Link to Laminopathies

Hallermann-Streiff syndrome (HSS) is a rare inherited disorder characterized by malformations of the cranium and facial bones, congenital cataracts, microphthalmia, skin atrophy, hypotrichosis, proportionate short stature, teeth abnormalities, and a typical facial appearance with prominent forehead, small pointed nose, and micrognathia. The genetic cause of this developmental disorder is presently unknown. Here we describe 8 new patients with a phenotype of HSS. Individuals with HSS present with clinical features overlapping with some progeroid syndromes that belong to the laminopathies, such as Hutchinson-Gilford progeria syndrome (HGPS) and mandibuloacral dysplasia (MAD). HGPS is caused by de novo point mutations in the LMNA gene, coding for the nuclear lamina proteins lamin A and C. MAD with type A and B lipodystrophy are recessive disorders resulting from mutations in LMNA and ZMPSTE24, respectively. ZMPSTE24 in addition to ICMT encode proteins involved in posttranslational processing of lamin A. We hypothesized that HSS is an allelic disorder to HGPS and MAD. As the nuclear shape is often irregular in patients with LMNA mutations, we first analyzed the nuclear morphology in skin fibroblasts of patients with HSS, but could not identify any abnormality. Sequencing of the genes LMNA, ZMPSTE24 and ICMT in the 8 patients with HSS revealed the heterozygous missense mutation c.1930C>T (p.R644C) in LMNA in 1 female. Extreme phenotypic diversity and low penetrance have been associated with the p.R644C mutation. In ZMPSTE24 and ICMT, no pathogenic sequence change was detected in patients with HSS. Together, we found no evidence that HSS is another laminopathy.

Pontine tegmental cap dysplasia: the severe end of the clinical spectrum

Pontine tegmental cap dysplasia (PTCD) is a newly described hindbrain malformation with distinct neuroradiological findings. Only 12 cases of PTCD have been described so far, all sporadic. We report 2 further patients. Both children presented after birth with significant feeding problems due to impaired mouth opening (previously not reported) and sucking difficulties. Facial, cochlear, and glossopharyngeal nerves were involved resulting in bilateral sensory deafness and a significant swallowing disorder requiring a gastrostomy. In one patient the trigeminal sensory nerve was also involved causing severe bilateral corneal clouding with impaired vision. Both patients showed only minimal developmental progress since birth and had no speech production. Furthermore, they had vertebral and rib anomalies. The patients died at the age of 15 and 32 months, respectively, due to intercurrent infections. The majority of patients reported previously were affected less severely. The presented patients may represent the severe end of the spectrum.

Three-generational alkaptonuria in a non-consanguineous family

OBJECTIVE

Alkaptonuria (AKU) is a rare inborn error of metabolism of aromatic amino acids and considered to be an autosomal recessive trait caused by mutations in the homogentisate 1,2-dioxygenase (HGD) gene. A dominant pattern of inheritance has been reported but was attributed to extended consanguinity in many cases. However, we have observed a non-consanguineous family segregating AKU in a dominant manner over three generations.

RESULTS

All affected individuals presented with typical features of AKU including darkening of the urine, ochronosis, arthropathy, and elevated urinary excretion of homogentisic acid. Sequence analysis of the HGD gene from genomic DNA of two affected individuals, uncle and niece, revealed a heterozygous missense mutation (M368V) in the uncle that was not present in his niece. Microsatellite genotyping demonstrated that both were heterozygous at the HGD locus and shared one haplotype. This haplotype did not contain a detectable HGD mutation. The haplotype was also found in a healthy son of the niece, making a dominant HGD mutation unlikely. Moreover, sequencing of cDNA from lymphoblastoid cells of the niece did not reveal an HGD mRNA with a potentially dominant-negative effect.

CONCLUSION

Rare causes of the uncommon AKU inheritance in this family have to be considered, ranging from the coincidence of undetectable HGD mutations to a dominant mutation of a second, hitherto unknown AKU gene.

Fluoreszenz-in-situ-Hybridisierung in der humangenetischen Diagnostik

Die humangenetische Diagnostik umfasst eine Vielzahl von Verfahren, die sich aufgrund ihrer spezifischen Einsatzbedingungen und Anwendungsmöglichkeiten gegenseitig ergänzen. Mit der stetigen Entwicklung neuer Methoden ist es sinnvoll und notwendig, etablierte Techniken auf den Prüfstand zu stellen. Die Fluoreszenz-in-situ-Hybridisierung (FISH) ist eine Standardmethode in der genetischen Diagnostik und Forschung. Abhängig vom Design der Sonden ist es möglich, ganz individuell DNA-Abschnitte oder auch das gesamte Genom im Fluoreszenzmikroskop in Metaphasechromosomen, in Interphasezellkernen, in Gewebeschnitten oder in lebenden Zellen sichtbar zu machen. Besonders häufig wird die FISH-Technik in der humangenetischen Diagnostik für die Darstellung und Analyse von Mikrodeletionen, Translokationen, Inversionen und Insertionen, also von Strukturaberrationen der Chromosomen, sowie für die Charakterisierung von Markerchromosomen, zur Kartierung von Chromosomenbruchpunkten und zum Aneuploidiescreening im „pränatalen FISH-Schnelltest“ eingesetzt. Die Stärke der Methode liegt dabei in der Untersuchung einzelner Zellen, sodass auch genetisch heterogene Zellpopulationen (Mosaike) im untersuchten Gewebe mit hoher Sicherheit festgestellt oder ausgeschlossen werden können. Außerdem ist es möglich, die morphologischen und immunologischen Eigenschaften der Zellen bei der Auswertung zu berücksichtigen, sodass genetische Veränderungen bestimmten Zellarten zugeordnet werden können.

Stages of sleep pathology in spinocerebellar ataxia type 2 (SCA2)

BACKGROUND

Autosomal dominant spinocerebellar ataxia type 2 (SCA2) bears clinical and neuropathologic similarities to sporadic multisystem atrophy (MSA) or Parkinson disease, in which sleep pathology is well documented. However, those clinical entities have a marked variability of the reported sleep disturbances, and their etiology is heterogeneous. In contrast, the study of SCA2 provides an opportunity to examine a molecularly homogeneous patient group, in which disease stages can be defined not only based on disease duration and ataxia scores, but also with regard to modulatory effects of mutation size.

OBJECTIVE

To examine the presence and progression of sleep pathology in SCA2.

METHODS

We analyzed eight patients with disease durations of 3 to 31 years, all with medium size SCA2 expansions (CAG 38 to 49), using clinical scores, sleep interviews, and video-polysomnography (VPSG) recordings.

RESULTS

Almost all patients reported good subjective sleep quality and negated incidents of REM behavior disorder (RBD). At early disease stages, however, REM without atonia in four patients' VPSG suggested subclinical RBD. This was accompanied by a consistent reduction of REM density. In three patients at later SCA2 stages, REM sleep was undetectable, whereas slow wave sleep (SWS) was markedly increased at the cost of light sleep. Periodic leg movements, apnea, or hypopnea were not prominent.

CONCLUSIONS

Progressive loss of dream recall in spinocerebellar ataxia type 2 was found and correlated with stages of REM more than non-REM pathology in video-polysomnography. These stages correspond to the progressive atrophy from the pons, nigrostriatal projection, and locus ceruleus to the thalamus.

Towards characterization of palmoplantar keratoderma caused by gain-of-function mutation in loricrin: analysis of a family and review of the literature

Loricrin keratoderma is an autosomal dominant palmoplantar keratoderma heterogeneous in clinical appearance. We report a family with diffuse ichthyosis and honeycomb palmoplantar keratoderma but no occurrence of pseudoainhums or autoamputations. All patients were born as collodion babies and displayed prominent knuckle pads. We identified the previously reported mutation 730insG in LOR, which elongates loricrin by 22 amino acids because of delayed termination. As pseudoainhums are missing in all patients of the family reported, we propose two compulsory features of loricrin keratoderma: (i) honeycomb palmoplantar keratoderma and (ii) diffuse ichthyosiform dermatosis. Therefore we suggest that the condition should be described clinically as 'honeycomb palmoplantar keratoderma with ichthyosis'. Furthermore, we have assessed the amounts of transcript of LOR using pyrosequencing. This revealed an equal expression of mutant and wild-type alleles of LOR in an affected individual. These findings further underline the gain-of-function theory for mutant LOR in loricrin keratoderma.

Spectrum of single- and multiexon NF1 copy number changes in a cohort of 1,100 unselected NF1 patients

Neurofibromatosis type 1 (NF1), the most common tumor-predisposing disorder in humans, is caused by defects in the NF1 tumor-suppressor gene. Comprehensive mutation analysis applying RNA-based techniques complemented with FISH analysis achieves mutation detection rates of approximately 95% in NF1 patients. The majority of mutations are minor lesions, and approximately 5% are total gene deletions. We found 13 single- and/or multiexon deletions/duplications out of 1,050 detected mutations using our RNA-based approach in a cohort of 1,100 NF1 patients and confirmed these changes using multiplex ligation-dependent probe amplification (MLPA). With MLPA, we found another 12 novel multiexon deletion/duplications in 55 NF1 patients for whom analysis with multiple assays had not revealed a NF1 mutation, including 50 previously analyzed comprehensively. The extent of the 22 deletions and 3 duplications varied greatly, and there was no clustering of breakpoints. We also evaluated the sensitivity of MLPA in identifying deletions in a mosaic state. Furthermore, we tested whether the MLPA P122 NF1 area assay could distinguish between type I deletions, with breakpoints in low-copy repeats (NF1-LCRs), and type II deletions, caused by aberrant recombination between the JJAZ gene and its pseudogene. Our study showed that intragenic deletions and/or duplications represent only approximately 2% of all NF1 mutations. Although MLPA did not substantially increase the mutation detection rate in NF1 patients, it was a useful first step in a comprehensive mutation analysis scheme to quickly pinpoint patients with single- or multiexon deletions/duplications as well as patients with a total gene deletion who will not need full sequencing of the complete coding region.

The Kabuki syndrome: four patients with oral abnormalities

The aim of this paper is to report the oral signs and symptoms of four patients with Kabuki syndrome. All had oral abnormalities affecting the palate, teeth, and/or lips, including wide spacing between the teeth, screwdriver-shaped upper incisors, hypodontia, delayed tooth eruption, narrow spacing in the upper canine area, large pulp chambers of the upper incisors and permanent molars, external root resorption of the upper central incisors and permanent molars, a division of the lower third of the root canal in normally one-rooted teeth, tooth retention, retrognathia of the upper jaw, a high palate or cleft lip/palate, and microforms of lower lip fistula.

Is the distribution of dermal neurofibromas in neurofibromatosis type 1 (NF1) related to the pattern of the skin surface temperature?

The formation of dermal neurofibromas is a hallmark of the neurofibromatosis type 1 (NF1). A total loss of the NF1 gene product by stochastic events inactivating the wild type allele in Schwann cells should precede the development of neurofibromas. Dermal neurofibromas tend to be located mainly on the surface of the trunk and not in the body periphery. This distribution partly resembles the density of sensitive nerve endings in the epidermis. Our hypothesis is that a better correlation concerns the pattern of normal body surface temperature. According to our clinical observations we assume that in skin areas with higher temperatures the number of visible dermal neurofibromas is higher than in colder areas such as the arms/legs or nose. It is known that differences in temperature are able to determine differentiation. We suggest that the regulation of skin temperature is also involved in the formation of NF1 dermal neurofibromas and is related to the intrafamilial variability in NF1.

Molecular characterization and gene content of breakpoint boundaries in patients with neurofibromatosis type 1 with 17q11.2 microdeletions

Homologous recombination between poorly characterized regions flanking the NF1 locus causes the constitutional loss of approximately 1.5 Mb from 17q11.2 covering > or =11 genes in 5%-20% of patients with neurofibromatosis type 1 (NF1). To elucidate the extent of microheterogeneity at the deletion boundaries, we used single-copy DNA fragments from the extreme ends of the deleted segment to perform FISH on metaphase chromosomes from eight patients with NF1 who had large deletions. In six patients, these probes were deleted, suggesting that breakage and fusions occurred within the adjacent highly homologous sequences. Reexamination of the deleted region revealed two novel functional genes FLJ12735 (AK022797) and KIAA0653-related (WI-12393 and AJ314647), the latter of which is located closest to the distal boundary and is partially duplicated. We defined the complete reading frames for these genes and two expressed-sequence tag (EST) clusters that were reported elsewhere and are associated with the markers SHGC-2390 and WI-9521. Hybrid cell lines carrying only the deleted chromosome 17 were generated from two patients and used to identify the fusion sequences by junction-specific PCRs. The proximal breakpoints were found between positions 125279 and 125479 in one patient and within 4 kb of position 143000 on BAC R-271K11 (AC005562) in three patients, and the distal breakpoints were found at the precise homologous position on R-640N20 (AC023278). The interstitial 17q11.2 microdeletion arises from unequal crossover between two highly homologous WI-12393-derived 60-kb duplicons separated by approximately 1.5 Mb. Since patients with the NF1 large-deletion syndrome have a significantly increased risk of neurofibroma development and mental retardation, hemizygosity for genes from the deleted region around the neurofibromin locus (CYTOR4, FLJ12735, FLJ22729, HSA272195 (centaurin-alpha2), NF1, OMGP, EVI2A, EVI2B, WI-9521, HSA272196, HCA66, KIAA0160, and WI-12393) may contribute to the severe phenotype of these patients.

Metaphyseal dysplasia: a new autosomal dominant type in a large German kindred

We describe a new autosomal dominant type of metaphyseal dysplasia (MD) in five generations of a German kindred. The main characteristics are metaphyseal widening and undermodeling of the tubular bones with Erlenmeyer flask-like appearance of the distal femora (typical of MD), with unusually severe varus deformity of the radii and flat exostoses of the long bones localized in the metaphyses. The skull is unaffected. Allelism with craniometaphyseal dysplasia (CMD) was excluded by linkage analysis.

Refinement of the chromosome 5p locus for craniometaphyseal dysplasia

Craniometaphyseal dysplasia--Jackson type (CMDJ) is an autosomal dominant bone dysplasia with hyperostosis and sclerosis of the skull and abnormal modelling of the metaphyses. In a large German pedigree, a locus for CMDJ has been mapped previously to the short arm of chromosome 5 (5p15.2-p14.1), defining a 19-cM disease interval between markers D5S2004 and D5S502. Analysis of a large Australian pedigree together with a second German family confirms linkage to the same region. Obligate recombinations in the new families and confirmation of a supposed recombination in the previously reported German kindred have enabled us to narrow the critical region down to approximately 4 cM between markers D5S1987 and D5S1991.

Heterozygous mutations in ANKH, the human ortholog of the mouse progressive ankylosis gene, result in craniometaphyseal dysplasia

Craniometaphyseal dysplasia (CMD) is a bone dysplasia characterized by overgrowth and sclerosis of the craniofacial bones and abnormal modeling of the metaphyses of the tubular bones. Hyperostosis and sclerosis of the skull may lead to cranial nerve compressions resulting in hearing loss and facial palsy. An autosomal dominant form of the disorder (MIM 123000) was linked to chromosome 5p15.2-p14.1 (ref. 3) within a region harboring the human homolog (ANKH) of the mouse progressive ankylosis (ank) gene. The ANK protein spans the outer cell membrane and shuttles inorganic pyrophosphate (PPi), a major inhibitor of physiologic and pathologic calcification, bone mineralization and bone resorption. Here we carry out mutation analysis of ANKH, revealing six different mutations in eight of nine families. The mutations predict single amino acid substitutions, deletions or insertions. Using a helix prediction program, we propose for the ANK molecule 12 membrane-spanning helices with an alternate inside/out orientation and a central channel permitting the passage of PPi. The mutations occur at highly conserved amino acid residues presumed to be located in the cytosolic portion of the protein. Our results link the PPi channel ANK with bone formation and remodeling.

[Variable expression of lower lip fistulas in Van der Woude syndrome]

Eight families with the combination of cleft lip and/or cleft palate plus lower lip pits including their microforms were examined with the aim of characterization of microsymptoms. Hypodontia as a further symptom was also taken into consideration. Each of the symptoms was also noted separately in relatives of the patients and are to be considered as a genetic equivalent of the complete form of the autosomal-dominant inherited Van der Woude's syndrome. Knowledge of the variable expression of the basic gene is crucial for risk assessment in family counselling and also for distinguishing from clefts of other genesis with lower recurrence risk.

Mutation screening of neurofibromatosis type 1 (NF1) exons 28 and 29 with single strand conformation polymorphism (SSCP): five novel mutations, one recurrent transition and two polymorphisms in a panel of 118 unrelated NF1 patients. Mutations in brief no. 229. Online

Neurofibromatosis type 1 is a clinically variable disorder caused mostly by small mutations within the NF1 gene on chromosome 17q11.2. We used Single Strand Conformation Polymorphism (SSCP) and radioactive sequencing to screen NF1 exons 28 and 29 from 118 unrelated patients, diagnosed with NF1 according to the NIH criteria, identifying five novel and one recurrent germline mutations, two novel polymorphisms and a variant base exchange. All but one cause protein truncation and represent typical NF1 mutations. There are reports that NF1 patients with mutations in exons 28 and 29 could be at greater risk of developing myeloid leukemia. This question was given consideration in this investigation, but none of the children involved have yet shown any symptoms of myeloid leukemia. 4 out of the 6 mutations were de novo.

Segmental neurofibromatosis is caused by somatic mutation of the neurofibromatosis type 1 (NF1) gene

Segmental neurofibromatosis (NF) is generally thought to result from a postzygotic NF1 (neurofibromatosis type 1) gene mutation. However, this has not yet been demonstrated at the molecular level. Using fluorescence in situ hybridisation (FISH) we identified an NF1 microdeletion in a patient with segmental NF in whom café-au-lait spots and freckles are limited to a single body region. The mutant allele was present in a mosaic pattern in cultured fibroblasts from a café-au-lait spot lesion, but was absent in fibroblasts from normal skin as well as in peripheral blood leukocytes. These findings prove the hypothesis that the molecular basis of segmental cutaneous NF is a mutation in the NF1 gene and that the regional distribution of manifestations reflects different cell clones, commensurate with the concept of somatic mosaicism.

A common set of at least 11 functional genes is lost in the majority of NF1 patients with gross deletions

Large deletions of the NF1 locus occur in 5 to 10% of patients with neurofibromatosis and are commonly associated with specific additional abnormalities characterized by mental retardation, dysmorphic features, and intellectual impairment. To characterize the extent of codeleted genes we constructed a long-range physical BAC/PAC map around the NF1 locus between D17S117 and D17S57 and determined the deletion boundaries in seven unrelated patients. Surprisingly, the proximal and distal breakpoints in five of seven patients fall at almost identical positions, resulting in the loss of at least 11 functional genes. Five of six patients investigated showed a de novo deletion on the maternally derived chromosome. Since D17S117 and D17S57 were previously reported as the outer limits for the great majority of NF1 deletions, we suggest that most NF1 patients with deletion of the entire NF1 gene are hemizygous for the same set of at least 10 additional genes, including SHGC-37343, SHGC-2390, SHGC-34232, OMG, EVI2B, EVI2A, WI-9521, WI-6742, SHGC-34334, and KIAA0160, and thus present with a relatively uniform clinical phenotype.

Analysis of the NF1 gene by temperature gradient gel electrophoresis reveals a high incidence of mutations in exon 4b

A total of 196 unrelated patients with neurofibromatosis type 1 (NF1) was screened for mutations in exons 4a-c of the NF1 gene by temperature gradient gel electrophoresis (TGGE) of polymerase chain reaction (PCR)-amplified genomic DNA fragments using intron-based primers. DNA samples with abnormal TGGE band patterns were subjected to sequence analysis. Sequence alterations were identified in ten patients (5.1%): 496delGT (1), 499delTGTT (4), T528A = D176E (2), T539A = L180X (1), 540insA (1), C574T = R192X (1). Thus, a total of six different mutations was identified in exon 4b but none in exons 4a and 4c. Only the missense mutation D176E, which we assume to be a nonpathogenic polymorphism, and the 4-base pair (bp) deletion 499delTGTT have been described before. The reason for the high incidence of mutations in exon 4b is obviously a tetranucleotide tandem repeat comprising nucleotides 495-502 (TGTTTGTT) that may give rise to slipped mispairing and subsequent deletion of one repeat unit during replication. Additionally, the recurrent 4 bp deletion was found as a second hit in a malignant schwannoma of a further NF1 patient, suggesting that microlesions may be as frequent among somatic as among germline mutations. This is the first report of a systematic study of NF1 exons 4a-c in a large group of NF1 patients.

Autosomal recessive versus autosomal dominant inheritance in Larsen syndrome: report of two affected sisters

Two sisters with Larsen syndrome are presented. The clinically unaffected parents originate from the South of Egypt and are first cousins. Further family history was non-contributory. Autosomal recessive inheritance of Larsen syndrome is most likely in this family.

Recurrent NF1 gene mutation in a patient with oligosymptomatic neurofibromatosis type 1 (NF1)

We report a 21-year-old male with symptomatic optic glioma who does not fulfill the diagnosis of neurofibromatosis 1 (NF1) according to standard NIH criteria. Analysis of the NF1 gene revealed a recurrent mutation in exon 37 (C6792A or Y2264X). This nonsense mutation causes skipping of exon 37 during the splicing process and is predicted to result in a protein shortened by 34 amino acid residues. The mutation was detected in all tissues examined (blood lymphocytes, oral mucosa, and dermal fibroblasts). The same mutation was previously found in 3 patients with clinically confirmed NF1. To our knowledge, this is the first report of an adult patient carrying a putative (non-mosaic) NF1 gene mutation in multiple tissues but not fulfilling the NIH criteria for the clinical diagnosis of NF1.

Fetal trisomy 10 mosaicism: ultrasound, cytogenetic and morphologic findings in early pregnancy

We report the ultrasound, cytogenetic and morphologic findings in a case of trisomy 10 mosaicism prenatally detected by chorionic villus sampling (CVS). CVS sampling was carried out at the 13th week of gestation because of ultrasound diagnosis of hydrops fetalis and hygroma colli. Trisomy 10 mosaicism was diagnosed in cells from the cytotrophoblast (short-term culture) and the chorionic villus core (long-term culture). Fetal mosaicism was confirmed after termination of pregnancy in umbilical cord cells, placenta and fetal skin fibroblasts.

McCune-Albright syndrome: clinical and molecular evidence of mosaicism in an unusual giant patient

Molecular genetics recently uncovered the mystery of the protean picture of McCune-Albright syndrome by identification of the somatic gain of function mutations in the GNAS1 gene. Here we present an adult patient with fibrous dysplasia and an endocrinopathy resulting in unusual giant height. The clinical diagnosis in the patient could be confirmed by molecular investigations in tissues involved in the process of fibrous dysplasia.

Two independent mutations in a family with neurofibromatosis type 1 (NF1)

We report on two independent alterations of the NF1 gene in a three-generation kindred with neurofibromatosis type 1 (NF1). Using temperature gradient gel electrophoresis (TGGE) in a mutation analysis of exon 31 of the NF1 gene we detected the previously reported nonsense mutation R1947X. This C-to-T transition at codon 1947 in exon 31 is considered to represent a mutation "hot spot" of the NF1 gene due to 5mCpG deamination. All living family members together with their genomic DNA were included in this investigation. However, the mutation R1947X was absent from two undoubtedly affected siblings of the propositus. Another NF1 mutation (889-2A-->G) was identified in the two sibs by the protein truncation test (PTT). The novel splice site mutation 889-2A-->G results in a skip of NF1 exon 7 during splicing and protein truncation due to frameshift. The two NF1 alterations are linked to different paternal haplotypes. In our study of a three-generation kindred, R1947X represents a de novo mutation whereas 889-2A-->G is an inherited splice mutation. Implications for phenotype variation are discussed.

Spontaneous remission of chiasmatic/hypothalamic masses in neurofibromatosis type 1: report of two cases

We report two children with neurofibromatosis type 1 showing enhancing masses on MRI suggesting neoplasms in the chiasm and hypothalamic region. In both patients no visual or endocrinal dysfunction was present. On serial MRI spontaneous partial remission was found, implying that a cautious approach to therapeutic management of similar cases should be taken.

Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome

We report on a 13-year-old patient followed since birth. He is the only offspring of young, non-consanguineous German parents. His mother has an isolated left cleft of lip and a cleft palate. At birth, our patient presented with bilaterally cleft lip/cleft palate, phocomelia of upper limbs with normal hands, and mild symmetrical deficiencies of the long bones of the lower limbs. Haematological evaluation demonstrated a leukaemoid reaction during a urinary tract infection as well as intermittent thrombocytopenia and episodes of marked eosinophilia during the first two years of life. Intellectual development has been normal. Comparison with two similar cases from the literature suggests a non-random phenotypic overlap of Roberts syndrome (MIM 268300) and TAR syndrome (MIM 274000). Such clinical constellations may be key observations to understand the genetic relationship of Roberts syndrome and TAR syndrome in future phenotype-genotype correlations.

Craniometaphyseal dysplasia in six generations of a German kindred

Craniometaphyseal dysplasia (CMD) was found in 6 generations of a large German kindred; 24 affected individuals were identified. The clinical diagnosis was confirmed by further examinations in 15 individuals, including 2 exhumed skeletons. Five deceased individuals were considered to be undoubtedly affected by reviewing photographs, and 4 must have had CMD from genealogical considerations. Pedigree analysis was performed over 8 generations back to persons born at the beginning of the 18th century in a central area of Germany. The trait could be traced back to a common male ancestor, born in 1790. Molecular genetic investigations on 3 generations of this kindred are in progress. In the present study we describe the clinical characteristics of the family.

Two novel mutations in exons 19a and 20 and a BsaBI [correction of BsaI] polymorphism in a newly characterized intron of the neurofibromatosis type 1 gene

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder. It is caused by mutations in the NF1 gene, which comprises 60 exons and is located on chromosome 17q11.2. A total of 170 unrelated NF1 patients were screened for mutations in four exons by temperature-gradient gel electrophoresis. Preparatory work revealed the presence of a previously uncharacterized intron (19a) in what was previously designated exon 19; this allowed us to develop assays for genomic mutation screening in the newly defined exons 19a and 19b. Two novel NF1 mutations were detected: a single-base insertion in exon 19a creating a frameshift, and a second mutation affecting the splice donor site of intron 20 and leading to skipping of exon 20. A novel BsaBI polymorphism was identified in intron 19a.

Tetraphocomelia and bilateral cleft lip in a historical case of Roberts syndrome [Virchow, 1898]

We discuss an unlabelled specimen of tetraphocomelia and bilaterally cleft lip from the former Virchow Museum of our Medical School. Identity of the subject with a case of what was later termed "Roberts syndrome" published by Rudolf Virchow in 1898 is demonstrated. Rediscovery of this important historical case is gratifying, since almost 95% of the specimens of Virchow's collection were lost during World War II. We have restudied Virchow's case. Recent CT scan images of the fetus are presented. We review data from the literature and present new clinical details. The fate of the original clinical data after passing through three reviews is documented briefly. We also reconstruct Virchow's view on phocomelia and its consequences for later research.

The gene for autosomal dominant craniometaphyseal dysplasia maps to chromosome 5p and is distinct from the growth hormone-receptor gene

Craniometaphyseal dysplasia (CMD) is an osteochondrodysplasia of unknown etiology characterized by hyperostosis and sclerosis of the craniofacial bones associated with abnormal modeling of the metaphyses. Sclerosis of the skull may lead to asymmetry of the mandible, as well as to cranial nerve compression, that finally may result in hearing loss and facial palsy. We have analyzed a large German kindred with autosomal dominant (AD) CMD and found tight linkage between the disorder and microsatellite markers on chromosome 5p (maximum two-point LOD score 4.82; theta = 0). Our results clearly establish the existence of a locus for AD CMD on central chromosome 5p (5p15.2-p14.1). This region overlaps with the mapping interval of the growth hormone-receptor (GHR) gene (5p14-p12), which is known to be involved in the mitogenic activation of osteoblasts. Therefore, we tested the GHR gene as a candidate gene. However, recombination events between the CMD locus and the GHR gene identified in two members of this family clearly exclude this candidate.

SCA2 trinucleotide expansion in German SCA patients

Autosomal dominant spinocerebellar ataxias (SCA) are a group of clinically and genetically heterogeneous neurodegenerative disorders which lead to progressive cerebellar ataxia. A gene responsible for SCA type 2 has been mapped to human chromosome 12 and the disease causing mutation has been identified as an unstable and expanded (CAG)n trinucleotide repeat. We investigated the (CAG)n repeat length of the SCA2 gene in 842 patients with sporadic ataxia and in 96 German families with dominantly inherited SCA which do not harbor the SCA1 or MJD1/SCA3 mutation, respectively. The SCA2 (CAG)n expansion was identified in 71 patients from 54 families. The (CAG)n stretch of the affected allele varied between 36 and 64 trinucleotide units. Significant repeat expansions occurred most commonly during paternal transmission. Analysis of the (CAG)n repeat lengths with the age of onset in 41 patients revealed an inverse correlation. Two hundred and forty-one apparently healthy octogenerians carried alleles between 16 and 31 repeats. One 50-year old, healthy individual had 34 repeats; she had transmitted an expanded allele to her child. The small difference between 'normal' and disease alleles makes it necessary to define the extreme values of their ranges. With one exception, the trinucleotide expansion was not observed in 842 ataxia patients without a family history of the disease. The SCA2 mutation causes the disease in nearly 14% of autosomal dominant SCA in Germany.

Patchy dermal hypoplasia as a characteristic feature of Proteus syndrome

BACKGROUND

The diagnostic criteria of Proteus syndrome include various lesions of localized overgrowth such as digital gigantism, hemihyperplasia with unilateral macrocephaly, epidermal nevus, and mesodermal hamartomas such as lipoma, lymphangioma, hemangioma, or fibroma. Hyperplasia of the plantar dermal tissue may result in a characteristic cerebriform appearance. However, hypoplastic lesions involving various tissues such as subcutaneous fat or muscles also may be observed in this syndrome. This paradoxical phenomenon has so far been underestimated, and the presence of circumscribed lesions of dermal hypoplasia has been entirely ignored.

OBSERVATIONS

We report 4 cases of Proteus syndrome associated with large patches of dermal hypoplasia, resulting in a more prominent appearance of venous vasculature.

CONCLUSIONS

Patchy dermal hypoplasia appears to be a characteristic feature within the spectrum of Proteus syndrome. The anomaly should not be confused with partial lipohypoplasia that may likewise be associated with this multisystem birth defect. From a review of the literature, we conclude that patchy dermal hypoplasia may have occurred in several previous cases. In the future, recognition of this cutaneous anomaly may help to establish the diagnosis in otherwise doubtful cases. To explain the coexistence of lesions of dermal hyperplasia and hypoplasia, we propose the genetic concept of "twin spotting." At the gene locus of Proteus syndrome the embryo would carry 1 allele giving rise to dermal overgrowth, whereas the corresponding allele would be responsible for a diminished proliferation of cutaneous fibroblasts. Somatic recombination may result in 2 different populations of cells homozygous for either allele.

Three novel mutations of the NF1 gene detected by temperature gradient gel electrophoresis of exons 5 and 8

We screened a total of 100 unrelated patients with neurofibromatosis type 1 (NF1) for mutations on exons 5 and 8 of the NF1 gene using temperature gradient gel electrophoresis (TGGE). Careful interpretation of exon 5 TGGE patterns was necessary due to interference by an exonic polymorphism. Three novel mutations were identified: a stop mutation in exon 5 (Q239X) caused by a C-->T transition at cDNA nucleotide position 715, a transition at the invariant G of the splice acceptor site in the intron 4c (G655-1A), and a transversion at the invariant G of the splice donor site in intron 8 (G1185 + 1T). Analysis of mRNA revealed the predicted abnormal splice products. While skipping of exon 5 causes a shift in the reading frame with a premature stop codon downstream in the middle of exon 6, skipping of exon 8 leads to an in-frame deletion with the predicted protein product being shortened by 41 amino acids.

Zunich neuroectodermal syndrome: migratory ichthyosiform dermatosis, colobomas, and other abnormalities

We report a 21-month-old girl with symptoms consistent with the Zunich neuroectodermal syndrome, an apparently rare condition first described in 1983. Common features of all previously reported patients as well as in this child are characteristic craniofacial dysmorphism, bilateral colobomas of the retina, sparse and fine hair, hearing loss, ichthyosiform erythroderma, mental retardation, ear anomalies, brachydactyly, and broad second toes. Light microscopic and ultrastructural investigations of the affected skin showed characteristic but nonspecific changes. The structural hair shaft abnormalities as well as the dysplastic nails in our patient have not been described before and are consistent with the previous assumption of an ectodermal dysplasia syndrome.

Two recurrent nonsense mutations and a 4 bp deletion in a quasi-symmetric element in exon 37 of the NF1 gene

We screened a total of 92 unrelated patients with neurofibromatosis type 1 (NF1) for mutations in exon 37 of the NF1 gene, by using temperature gradient gel electrophoresis. Two novel mutations were found: a 4 bp deletion in a so-called quasi-symmetric element (6789del-TTAC) and a recurrent nonsense mutation, which was identified in two unrelated patients, at codon 2264 (C6792A). The independent origin of the latter mutation in two families was confirmed by haplotype analysis. The nonsense mutation and the 4 bp deletion are both predicted to lead to a truncated protein product lacking the C-terminal 20% (approximately) of its sequence. The occurrence of three independent mutations among 92 NF1 patients at codons 2263-2264 (exon 37) suggests that a specific search for mutations in this area should be undertaken in screening programs for NF1 mutations.

Spectrum of X-linked hydrocephalus (HSAS), MASA syndrome, and complicated spastic paraplegia (SPG1): Clinical review with six additional families

X-linked hydrocephalus (HSAS) (MIM *307000), MASA syndrome (MIM *303350), and complicated spastic paraplegia (SPG1) (MIM *312900) are closely related. Soon after delineation, SPG1 was incorporated into the spectrum of MASA syndrome. HSAS and MASA syndrome show great clinical overlap; DNA linkage analysis places the loci at Xq28. In an increasing number of families with MASA syndrome or HSAS, mutations in L1CAM, a gene located at Xq28, have been reported. In order to further delineate the clinical spectrum, we studied 6 families with male patients presenting with MASA syndrome, HSAS, or a mixed phenotype. We summarized data from previous reports and compared them with our data. Clinical variability appears to be great, even within families. Problems in genetic counseling and prenatal diagnosis, the possible overlap with X-linked corpus callosum agenesis and FG syndrome, and the different forms of X-linked complicated spastic paraplegia are discussed. Since adducted thumbs and spastic paraplegia are found in 90% of the patients, the condition may be present in males with nonspecific mental retardation. We propose to abandon the designation MASA syndrome and use the term HSAS/MASA spectrum, incorporating SPG1.

The Kabuki (Niikawa-Kuroki) syndrome: further delineation of the phenotype in 29 non-Japanese patients

The Kabuki (Niikawa-Kuroki) syndrome was reported in 1981 by Niikawa et al. and Kuroki et al. in a total of ten unrelated Japanese children with a characteristic array of multiple congenital anomalies and mental retardation. The syndrome is characterized by a distinct face, mild to moderate mental retardation, postnatal growth retardation, dermatoglyphic and skeletal abnormalities. In Japan, the syndrome appears to have an incidence of about 1:32,000 newborns. Outside of Japan, a growing number of patients have been recognized. Clinical data are presented on 29 Caucasian patients; the patients were diagnosed over a relatively short period of time, indicating that the incidence outside of Japan is probably not lower than in Japan. A literature review of 89 patients (60 Japanese and 29 non-Japanese) is given. In 66% of the non-Japanese patients serious neurological problems were present, most notably hypotonia and feeding problems (which were not only related to the cleft palate); this was not reported in the Japanese patients. Inheritance is not clear. Most patients are isolated, sex-ratio is equal. The syndrome can be recognized in patients with cleft (lip/)palate, with mild to moderate developmental delay and in young children with hypotonia and/or feeding problems. In counselling parents, the designation "Kabuki" syndrome seems to be more appropriate than "Kabuki make-up" syndrome.

Routine applications of DNA fingerprinting with the oligonucleotide probe (CAC)5/(GTG)5

The use of DNA fingerprinting with synthetic oligonucleotides is illustrated for practical applications familiar in clinical diagnostics: pre- and postnatal zygosity determination and the monitoring of bone marrow transplantation. A simple method for non-radioactive detection is described which may be interesting for many diagnostic laboratories.