The many faces of aggressive aortic pathology: Loeys-Dietz syndrome

Background: Loeys-Dietz syndrome (LDS) is a newly recognised disorder of connective tissue which shares overlapping features with Marfan syndrome (MFS) and the vascular type of Ehlers- Danlos syndrome, including aortic root dilatation and skin abnormalities. It is clinically classified into types 1 and 2. LDS type 1 can be recognised by craniofacial characteristics, e.g. hypertelorism, bifid uvula or cleft palate, whereas these are absent in LDS type 2. It is important to recognise LDS because its vascular pathology is aggressive. We describe nine LDS patients from four families, relate their features to published cases, and discuss important aspects of the diagnosis and management of LDS in order to make clinicians aware of this new syndrome. Results: Characteristics found in the majority of these LDS patients were aortic root dilatation, cleft palate and/or a bifid/abnormal uvula. Conclusion: Because aortic dissection and rupture in LDS tend to occur at a young age or at aortic root diameters not considered at risk in MFS, and because the vascular pathology can be seen throughout the entire arterial tree, patients should be carefully followed up and aggressive surgical treatment is mandatory. Clinicians must therefore be aware of LDS as a cause of aggressive aortic pathology and that its distinguishing features can sometimes be easily recognised. (Neth Heart J 2008;16:299-304.)     

Long-term follow-up of a girl with oro-facio-digital syndrome type I due to a mutation in the OFD 1 gene

In 1954, Papillon-Léage and Psaume described a dominant, X-linked condition which they named oro-facio-digital (OFD). This condition was split into at least nine syndromes, the more common being OFD I. We report a girl with OFD I syndrome followed up for 23 years. Clinical examination showed cleft palate, median cleft lip, multiple oral frenulae, lobulated tongue and brachydactyly. There was no mental retardation. At 19 years of age, renal insufficiency appeared. A renal transplantation was performed. The parents were unaffected. An older brother had hydrocephaly, bilateral optic atrophy and mental retardation. A younger sister is unaffected. A mutation, an insertion of a G leading to a frameshift in the OFD 1 gene, was identified in this patient.     

Cell autonomous requirement for Tgfbr2 in the disappearance of medial edge epithelium during palatal fusion

Palatal fusion is a complex, multi-step developmental process; the consequence of failure in this process is cleft palate, one of the most common birth defects in humans. Previous studies have shown that regression of the medial edge epithelium (MEE) upon palatal fusion is required for this process, and TGF-beta signaling plays an important role in regulating palatal fusion. However, the fate of the MEE and the mechanisms underlying its disappearance are still unclear. By using the Cre/lox system, we are able to label the MEE genetically and to ablate Tgfbr2 specifically in the palatal epithelial cells. Our results indicate that epithelial-mesenchymal transformation does not occur in the regression of MEE cells. Ablation of Tgfbr2 in the palatal epithelial cells causes soft palate cleft, submucosal cleft and failure of the primary palate to fuse with the secondary palate. Whereas wild-type MEE cells disappear, the mutant MEE cells continue to proliferate and form cysts and epithelial bridges in the midline of the palate. Our study provides for the first time an animal model for soft palate cleft and submucous cleft. At the molecular level, Tgfb3 and Irf6 have similar expression patterns in the MEE. Mutations in IRF6 disrupt orofacial development and cause cleft palate in humans. We show here that Irf6 expression is downregulated in the MEE of the Tgfbr2 mutant. As a recent study shows that heterozygous mutations in TGFBR1 or TGFBR2 cause multiple human congenital malformations, including soft palate cleft, we propose that TGF-beta mediated Irf6 expression plays an important, cell-autonomous role in regulating the fate of MEE cells during palatogenesis in both mice and humans.     

Fryns anophthalmia-plus syndrome with hypoplastic adrenal glands

We report a family with two consequent sibs with anophthalmia and cleft lip and palate. A 27 year old woman married to her first cousin was counseled for anophthalmia and cleft lip and palate detected during routine fetal ultrasonographic examination on the 23rd week of the pregnancy. Her obstetric history revealed a healthy girl aged 7 years and a boy with anophthalmia and cleft lip and palate who lived for 20 days in the neonatal intensive care unit. The current pregnancy was terminated after the diagnosis, and post mortem examination of the fetus revealed pre-maxilla agenesis, anophthalmia, cerebral ventricular dilatation, adrenal hypoplasia and single umbilical artery. Chromosome analysis resulted in normal karyotypes of the fetus and both parents. The inheritance pattern was regarded as autosomal recessive and the family was informed about the condition and risks during genetic counseling.     

Morphology of the orbital region in adults following the cleft lip-palate repair in childhood

Four measurements and two qualitative signs related to the orbits of 145 adult Caucasian cleft lip/palate patients operated on in childhood were compared with similar data on 100 normal Caucasian Canadians. The average interorbital distance in male patients with unilateral and bilateral cleft lip/palate was greater than in controls, while the interorbital distance in both male and female patients with isolated cleft palate was the same as that in controls. A hypertelorism increased interorbital distance of greater than 2 S.D. above the normal was recorded in 10 cleft patients out of 145, the maximum in male cleft patients being 48 mm and in female cleft patients 38 mm. Orbital eye fissure length asymmetry was seen only in the cleft study group while a dislocation of the eye fissure levels in the frontal plane was found both in patients with clefts and in controls. No direct relationship was found between the extent of the cleft and the incidence of hypertelorism, nor between the site of the cleft and eye fissure asymmetry in unilateral cleft lip/palate patients. The epicanthic fold was significantly more frequent in cleft lip/palate patients (28/145) than in controls (10/100). Anti-mongoloid eye fissure type was recorded only in patients with cleft but mongoloid eye fissure was present both in patients with clefts and controls.     

The Smith-Lemli-Opitz syndrome with a G303R/R352W mutation: in an extremely irritable child responsive to cholesterol supplementation

Smith-Lemli-Opitz syndrome(SLOS) is a hereditary disorder of cholesterol biosynthesis. It is characterized by growth deficiency, mental retardation and multiple congenital anomalies, including a typical facial appearance, cleft palate, syndactyly, and a variety of central nervous system and/or major congenital malformations. There are very few reports of the Smith-Lemli-Opitz syndrome in Korean children. Here, we report on a girl with a G303R/R352W mutation. The patient was extremely irritable; assessment of the severity of the irritability included severity scoring and the amount of sleep. Cholesterol supplementation was started with egg yolks, and the irritability improved.     

Localization of the Homolog of a Mouse Craniofacial Mutant to Human Chromosome 18q11 and Evaluation of Linkage to Human CLP and CPO

The transgene-induced mutation 9257 and the spontaneous mutation twirler cause craniofacial and inner ear malformations and are located on mouse chromosome 18 near the ataxia locusax.To map the human homolog of 9257, a probe from the transgene insertion site was used to screen a human genomic library. Analysis of a cross-hybridizing human clone identified a 3-kb conserved sequence block that does not appear to contain protein coding sequence. Analysis of somatic cell hybrid panels assigned the human locus to 18q11. The polymorphic microsatellite markers D18S1001 and D18S1002 were isolated from the human locus and mapped by linkage analysis using the CEPH pedigrees. The 9257 locus maps close to the centromeres of human chromosome 18q and mouse chromosome 18 at the proximal end of a conserved linkage group. To evaluate the role of this locus in human craniofacial disorders, linkage to D18S1002 was tested in 11 families with autosomal dominant nonsyndromic cleft lip and palate and 3 families with autosomal dominant cleft palate only. Obligatory recombinants were observed in 8 of the families, and negative lod scores from the other families indicated that these disorders are not linked to the chromosome 18 loci.     

Variable expression of an autosomal dominant syndrome: (BBB syndrome or G syndrome)

We report a family in which Opitz-Frias G syndrome is expressed across 4 generations. The propositus displays hypertelorism, low grade hypospadias, cleft palate and lips and cleft larynx, making the diagnosis of G syndrome very likely. A cousin of his mother discloses similar clefts, vulviform hypospadias, anal imperforation and mental retardation. His clinical appearance fits perfectly the diagnosis of BBB syndrome. A nephew shows ambiguous genitalia and hypertelorism. Authors suggest the lumping of the BBB and the G syndrome.     

Congenital lateral cleft palate: a new anomaly?

A case of atypical cleft palate abnormality that had not been identified before in a 9-year-old girl is presented. The cleft was localized laterally and in an oblique position at the soft palate. The patient had cleft palate repair. Finally, she had acceptable soft palate movements and speech.     

Association of five SNPs with human hair colour in the Polish population

Twenty-two variants (single nucleotide polymorphisms – SNPs) of the genes involved in hair pigmentation (OCA2, HERC2, MC1R, SLC24A5, SLC45A2, TPCN2, TYR, TYRP1) were genotyped in a group of 186 Polish participants, representing a range of hair colours (45 red, 64 blond, 77 dark). A genotype-phenotype association analysis was performed.Using z-statistics we identified three variants highly associated with different hair colour categories (rs12913832:A>G in HERC2, rs1805007:T>C and rs1805008:C>T in MC1R). Two variants: rs1800401:C>T in OCA2 and rs16891982:C>G in SLC45A2 showed a high probability of a relation with hair colour, although that probability did not exceed the threshold of statistical significance after applying the Bonferroni correction. We created and validated mathematical logistic regression models in order to test the usefulness of the sets of polymorphisms for hair colour prediction in the Polish population. We subjected four models to stratified cross-validation. The first model consisted of three polymorphisms that proved to be important in the associative analysis. The second model included, apart from the mentioned polymorphisms, additionally rs16891982:C>G in SLC45A. The third model included, apart from the variants relevant in the associating analysis, rs1800401:C>T in OCA. The fourth model consisted of the set of polymorphisms from the first model supplemented with rs16891982:C>G in SLC45A and rs1800401:C>T in OCA. The validation of our models has shown that the inclusion of rs16891982:C>G in SLC45A and rs1800401:C>T in OCA increases the prediction of red hair in comparison with the algorithm including only rs12913832:A>G in HERC2, rs1805007:T>C and rs1805008:C>T in MC1R. The model consisting of all the five above-mentioned genetic variants has shown good prediction accuracies, expressed by the area under the curve (AUC) of the receiver operating characteristics: 0.84 for the red-haired, 0.82 for the dark-haired and 0.71 for the blond-haired.A genotype-phenotype association analysis brought results similar to those in other studies and confirmed the role of rs16891982:C>G, rs12913832:A>G, rs1805007:T>C and rs1805008:C>T in hair colour determination in the Polish population. Our study demonstrated for the first time the possibility of a share of the rs1800401:C>T SNP in the OCA2 gene in hair colour determination. Including this single nucleotide polymorphism in the actual hair colour predicting models would improve their predictive accuracy.     

Heteroplasmic m.1624C>T mutation of the mitochondrial tRNAVal gene in a proband and his mother with repeated consciousness disturbances

Homoplasmic m.1624C>T mutation of the mitochondrial tRNA^Val gene was previously demonstrated to cause fatal neonatal Leigh syndrome. Here, we report the clinical phenotypes of a Japanese male and his mother with heteroplasmic m.1624C>T mutation. The 36-year-old male presented with repeated episodes of consciousness disturbance since the age of 25, cognitive decline, and personality change. Cerebrospinal fluid levels of lactate and pyruvate were elevated. His mother showed similar symptoms and course. The mutation m.1624C>T was identified heteroplasmically in the proband's muscle and leukocytes and in the mother's leukocytes. The heteroplasmy load decreased with age.     

Fryns syndrome with atypical findings--with large midline cleft on forehead but normal cranial MRI findings

We report a newborn with Fryns syndrome and atypical findings like a large midline cleft on forehead. Abnormal findings included congenital left diaphragmatic hernia, prominent forehead, hypertelorism, broad nasal bridge, anteverted nostrils, cleft palate, low set ears, tapered fingers, macrocephaly, congenital heart defect, midline defects and renal anomalies. This is the first case that has a midline cleft on forehead with normal cranial MRI findings.     

Matrix metalloproteinase-25 has a functional role in mouse secondary palate development and is a downstream target of TGF-β3

Background  

Development of the secondary palate (SP) is a complex event and abnormalities during SP development can lead to cleft palate, one of the most common birth disorders. Matrix metalloproteinases (MMPs) are required for proper SP development, although a functional role for any one MMP in SP development remains unknown. MMP-25 may have a functional role in SP formation as genetic scans of the DNA of human cleft palate patients indicate a common mutation at a region upstream of the MMP-25 gene. We report on the gene expression profile of MMP-25 in the developing mouse SP and identify its functional role in mouse SP development.     

Sonic hedgehog signalling inhibits palatogenesis and arrests tooth development in a mouse model of the nevoid basal cell carcinoma syndrome

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant or spontaneous disorder characterized by multiple cutaneous basal cell carcinomas, odontogenic keratocysts, skeletal anomalies and facial dysmorphology, including cleft lip and palate. Causative mutations for NBCCS occur in the PTCH1 gene on chromosome 9q22.3-q31, which encodes the principle receptor for the Hedgehog signalling pathway. We have investigated the molecular basis of craniofacial defects seen in NBCCS using a transgenic mouse model expressing Shh in basal epithelium under a Keratin-14 promoter. These mice have an absence of flat bones within the skull vault, hypertelorism, open-bite malocclusion, cleft palate and arrested tooth development. Significantly, increased Hedgehog signal transduction in these mice can influence cell fate within the craniofacial region. In medial edge epithelium of the palate, Shh activity prevents apoptosis and subsequent palatal shelf fusion. In contrast, high levels of Shh in odontogenic epithelium arrests tooth development at the bud stage, secondary to a lack of cell proliferation in this region. These findings illustrate the importance of appropriately regulated Hedgehog signalling during early craniofacial development and demonstrate that oro-facial clefting and hypodontia seen in NBCCS can occur as a direct consequence of increased Shh signal activity within embryonic epithelial tissues.     

Congenital malformations in a common marmoset (Callithrix jacchus) similar to human 13-trisomy syndrome

This paper describes the finding of a number of malformations in a live-born common marmoset. The malformations included microphthalmia, ocular hypertelorism, cleft lip and palate and polydactyly. The findings are consistent with and strongly suggest chromosome trisomy similar to that which has been seen in man.     

Intragenic deletions and a deep intronic mutation affecting pre-mRNA splicing in the dihydropyrimidine dehydrogenase gene as novel mechanisms causing 5-fluorouracil toxicity

Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme acting in the catabolism of the widely used antineoplastic agent 5-fluorouracil (5FU). DPD deficiency is known to cause a potentially lethal toxicity following administration of 5FU. Here, we report novel genetic mechanisms underlying DPD deficiency in patients presenting with grade III/IV 5FU-associated toxicity. In one patient a genomic DPYD deletion of exons 21–23 was observed. In five patients a deep intronic mutation c.1129–5923C>G was identified creating a cryptic splice donor site. As a consequence, a 44 bp fragment corresponding to nucleotides c.1129–5967 to c.1129–5924 of intron 10 was inserted in the mature DPD mRNA. The deleterious c.1129–5923C>G mutation proved to be in cis with three intronic polymorphisms (c.483 + 18G>A, c.959–51T>G, c.680 + 139G>A) and the synonymous mutation c.1236G>A of a previously identified haplotype. Retrospective analysis of 203 cancer patients showed that the c.1129–5923C>G mutation was significantly enriched in patients with severe 5FU-associated toxicity (9.1%) compared to patients without toxicity (2.2%). In addition, a high prevalence was observed for the c.1129–5923C>G mutation in the normal Dutch (2.6%) and German (3.3%) population. Our study demonstrates that a genomic deletion affecting DPYD and a deep intronic mutation affecting pre-mRNA splicing can cause severe 5FU-associated toxicity. We conclude that screening for DPD deficiency should include a search for genomic rearrangements and aberrant splicing.     

Roberts SC phocomelia with isolated cleft palate, thrombocytopenia, and eosinophilia.

The Roberts-SC (Pseudothalidomide) syndrome is a rare autosomal recessive disorder. We present a Roberts-SC Syndrome in a 20-day-old girl with phocomelia of the upper limbs, isolated cleft palate, micrognathia, prominent eyes, pectus excavatum, and pes equinovarus. Peripheral blood smear revealed thrombocytopenia and hypereosinophilia. Premature centromere separation in the child and also in her normal mother was noted.     

Frequency of lactase persistence genotype in a healthy Polish population

The majority of mammals are unable to digest lactose due to post-weaning deactivation of the LCT gene, which is responsible for encoding the enzyme lactase (i.e., adult-type hypolactasia). A substitution of C with T at position −13910 bp upstream of the LCT gene has been linked to the lactase persistence phenotype in European populations. We investigated the frequency of LCT-13910C>T polymorphism in 223 blood donors from central Poland. All samples were genotyped by polymerase chain reaction and direct sequencing. The LCT-13910 T allele (lactase persistence) was present in 51% of individuals sampled from the Polish population. We did not find any non-European variants associated with lactase persistence (LCT-13907C>G, LCT-13913T>C, LCT-13915T>G), or any new polymorphisms within the sequenced region. Allele frequencies obtained are in agreement with results from other countries and confirm the unique pattern of distribution of the LCT-13910C>T genotype in Europe.