Correction: Loss of the BMP Antagonist, SMOC-1, Causes Ophthalmo-Acromelic (Waardenburg Anophthalmia) Syndrome in Humans and Mice.

[This corrects the article DOI: 10.1371/journal.pgen.1002114.].

Analysis of centrosome and DNA damage response in PLK4 associated Seckel syndrome.

Microcephalic primordial dwarfism (MPD) is a group of autosomal recessive inherited single-gene disorders with intrauterine and postnatal global growth failure. Seckel syndrome is the most common form of the MPD. Ten genes are known with Seckel syndrome. Using genome-wide SNP genotyping and homozygosity mapping we mapped a Seckel syndrome gene to chromosomal region 4q28.1-q28.3 in a Turkish family. Direct sequencing of PLK4 (polo-like kinase 4) revealed a homozygous splicing acceptor site transition (c.31-3 A>G) that results in a premature translation termination (p.[=,Asp11Profs*14]) causing deletion of all known functional domains of the protein. PLK4 is a master regulator of centriole biogenesis and its deficiency has recently been associated with Seckel syndrome. However, the role of PLK4 in genomic stability and the DNA damage response is unclear. Evaluation of the PLK4-Seckel fibroblasts obtained from patient revealed the expected impaired centriole biogenesis, disrupted mitotic morphology, G2/M delay, and extended cell doubling time. Analysis of the PLK4-Seckel cells indicated that PLK4 is also essential for genomic stability and DNA damage response. These findings provide mechanistic insight into the pathogenesis of the severe growth failure associated with PLK4-deficiency.

Novel splice-site and missense mutations in the ALDH1A3 gene underlying autosomal recessive anophthalmia/microphthalmia.

AIM: This study aimed to identify the underlying genetic defect responsible for anophthalmia/microphthalmia. METHODS: In total, two Turkish families with a total of nine affected individuals were included in the study. Affymetrix 250 K single nucleotide polymorphism genotyping and homozygosity mapping were used to identify the localisation of the genetic defect in question. Coding region of the ALDH1A3 gene was screened via direct sequencing. cDNA samples were generated from primary fibroblast cell cultures for expression analysis. Reverse transcriptase PCR (RT-PCR) analysis was performed using direct sequencing of the obtained fragments. RESULTS: The causative genetic defect was mapped to chromosome 15q26.3. A homozygous G>A substitution (c.666G>A) at the last nucleotide of exon 6 in the ALDH1A3 gene was identified in the first family. Further cDNA sequencing of ALDH1A3 showed that the c.666G>A mutation caused skipping of exon 6, which predicted in-frame loss of 43 amino acids (p.Trp180_Glu222del). A novel missense c.1398C>A mutation in exon 12 of ALDH1A3 that causes the substitution of a conserved asparagine by lysine at amino acid position 466 (p.Asn466Lys) was observed in the second family. No extraocular findings-except for nevus flammeus in one affected individual and a variant of Dandy-Walker malformation in another affected individual-were observed. Autistic-like behaviour and mental retardation were observed in three cases. CONCLUSIONS: In conclusion, novel ALDH1A3 mutations identified in the present study confirm the pivotal role of ALDH1A3 in human eye development. Autistic features, previously reported as an associated finding, were considered to be the result of social deprivation and inadequate parenting during early infancy in the presented families.

Reduced elastogenesis: a clue to the arteriosclerosis and emphysematous changes in Schimke immuno-osseous dysplasia?

BACKGROUND: Arteriosclerosis and emphysema develop in individuals with Schimke immuno-osseous dysplasia (SIOD), a multisystem disorder caused by biallelic mutations in SMARCAL1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1). However, the mechanism by which the vascular and pulmonary disease arises in SIOD remains unknown. METHODS: We reviewed the records of 65 patients with SMARCAL1 mutations. Molecular and immunohistochemical analyses were conducted on autopsy tissue from 4 SIOD patients. RESULTS: Thirty-two of 63 patients had signs of arteriosclerosis and 3 of 51 had signs of emphysema. The arteriosclerosis was characterized by intimal and medial hyperplasia, smooth muscle cell hyperplasia and fragmented and disorganized elastin fibers, and the pulmonary disease was characterized by panlobular enlargement of air spaces. Consistent with a cell autonomous disorder, SMARCAL1 was expressed in arterial and lung tissue, and both the aorta and lung of SIOD patients had reduced expression of elastin and alterations in the expression of regulators of elastin gene expression. CONCLUSIONS: This first comprehensive study of the vascular and pulmonary complications of SIOD shows that these commonly cause morbidity and mortality and might arise from impaired elastogenesis. Additionally, the effect of SMARCAL1 deficiency on elastin expression provides a model for understanding other features of SIOD.

Loss of the BMP antagonist, SMOC-1, causes Ophthalmo-acromelic (Waardenburg Anophthalmia) syndrome in humans and mice.

Ophthalmo-acromelic syndrome (OAS), also known as Waardenburg Anophthalmia syndrome, is defined by the combination of eye malformations, most commonly bilateral anophthalmia, with post-axial oligosyndactyly. Homozygosity mapping and subsequent targeted mutation analysis of a locus on 14q24.2 identified homozygous mutations in SMOC1 (SPARC-related modular calcium binding 1) in eight unrelated families. Four of these mutations are nonsense, two frame-shift, and two missense. The missense mutations are both in the second Thyroglobulin Type-1 (Tg1) domain of the protein. The orthologous gene in the mouse, Smoc1, shows site- and stage-specific expression during eye, limb, craniofacial, and somite development. We also report a targeted pre-conditional gene-trap mutation of Smoc1 (Smoc1(tm1a)) that reduces mRNA to ∼10% of wild-type levels. This gene-trap results in highly penetrant hindlimb post-axial oligosyndactyly in homozygous mutant animals (Smoc1(tm1a/tm1a)). Eye malformations, most commonly coloboma, and cleft palate occur in a significant proportion of Smoc1(tm1a/tm1a) embryos and pups. Thus partial loss of Smoc-1 results in a convincing phenocopy of the human disease. SMOC-1 is one of the two mammalian paralogs of Drosophila Pentagone, an inhibitor of decapentaplegic. The orthologous gene in Xenopus laevis, Smoc-1, also functions as a Bone Morphogenic Protein (BMP) antagonist in early embryogenesis. Loss of BMP antagonism during mammalian development provides a plausible explanation for both the limb and eye phenotype in humans and mice.

Subtelomeric 6p monosomy and 12q trisomy in a patient with a 46,XX,der(6)t(6;12)(p25.3;q24.31) karyotype: Phenotypic overlap with Mutchinick syndrome.

We report on a patient with partial monosomy 6p and partial trisomy 12q identified by fluorescent in situ hybridization (FISH) and array-based comparative genomic hybridization (aCGH). She had a complex phenotype characterized by mental retardation (MR), psychomotor developmental delay, speech disorder, hypertelorism, eye anomalies, hearing loss, low-set malformed ears, thin upper lip, heart defect, clinodactyly, pes valgus, and skeletal anomalies. There is phenotypic overlap between our case and Mutchinick syndrome. This is the first report of a combined partial monosomy 6p and partial trisomy 12q due to an unbalanced translocation between subtelomeric regions of these chromosomes.

The EEC syndrome and SHFM: report of two cases and mutation analysis of p63 gene.

The p63 gene is a transcription factor and a member of the p53 family. Heterozygote mutation of the p63 gene is suggested in a number of human syndromes including limb development and/or ectodermal dysplasia. The EEC syndrome, consisting of ectrodactyly (E), ectodermal dysplasia (E) and cleft lip (C) with or without cleft palate, is the prototype of these syndromes with the presence of heterozygote mutation in the p63 gene in most of the patients. Nonsyndromic split hand/foot malformation (SHFM) is one of the EEC-like syndromes, and the p63 gene mutation was reported in only a few patients. Five different loci have been mapped to date, but the etiology is yet to be explained in the rest of the patients. Here, we report two cases. Case 1, diagnosed with EEC syndrome, had type 2 urogenital sinus and a new heterozygous mutation of 934G>A (D312N) in exon 8 of the p63 gene. Case 2 was diagnosed as SHFM with no mutation in the p63 gene. Genotype and phenotype correlation of these two cases among the reported patients is discussed in this report.

Fetal sodium valproate exposure causes Baller-Gerold syndrome phenotype: both phenotypes in the same family.

Baller-Gerold syndrome (BGS) is characterized by craniosynostosis and preaxial upper-limb malformations, and it has an autosomal recessive inheritance. Valproate syndrome occurs after exposure to valproic acid in utero, and is characterized by trigonocephaly. Both syndromes can also present with other malformations. Herein, we report a female newborn and her brother who both had a history of fetal exposure to maternal anti-epileptic drugs, especially sodium valproate. On physical examination of the female patient, craniosynostosis, trigonocephaly, right radius aplasia and hypoplastic thumb, and cardiac and renal malformations were determined, and she was diagnosed with BGS phenotype. The brother's examination revealed trigonocephaly, polymastia and hypospadias, and he was diagnosed with valproate syndrome. Based on these patients, we aimed to add further evidence in the literature indicating that the use of sodium valproate alone and in combination with other anti-epileptic drugs throughout pregnancy can increase the risk of serious fetal congenital malformations depending on the doses.

Serum or plasma cartilage oligomeric matrix protein concentration as a diagnostic marker in pseudoachondroplasia: differential diagnosis of a family.

Pseudoachondroplasia (PSACH) is an autosomal-dominant osteochondrodysplasia due to mutations in the gene encoding cartilage oligomeric matrix protein (COMP). Clinical diagnosis of PSACH is based primarily on family history, physical examination, and radiographic evaluation, and is sometimes extremely difficult, particularly in adult patients. Genetic diagnosis based on DNA sequencing, on the other hand, can be expensive, time-consuming, and intensive because COMP mutations may be scattered throughout the gene. However, there is evidence that decreased plasma COMP concentration may serve as a diagnostic marker in PSACH, particularly in adult patients. Here, we report the serum and/or plasma COMP concentration-based differential diagnosis of a family with affected adult members. The mean serum and/or plasma COMP concentrations of the three affected family members alive (0.69+/-0.15 and/or 0.81+/-0.08 microg/ml, respectively) were significantly lower than those of an age-compatible control group of 21 adults (1.52+/-0.37 and/or 1.37+/-0.36 microg/ml, respectively; P<0.0001). Bidirectional fluorescent DNA sequencing-based genetic diagnosis of these patients revealed a heterozygous mutation for the nucleotide change 1532A>G in exon 14 of the COMP gene, resulting in a substitution of amino acid 511 from aspartic acid to glycine in COMP. Thus, serum and/or plasma COMP concentration may be suggested as an additional diagnostic marker to aid clinical and radiographic findings in suspected cases of PSACH.

Detection of Y chromosomal material in patients with a 45,X karyotype by PCR method.

A 45,X karyotype is one of the common chromosomal abnormalities characterized by short stature, lack of development of secondary sexual characteristics, webbed neck and cubitus valgus. This phenotype was described by Turner in 1938 and was called Turner syndrome (TS). About 40-60% of the patients with TS phenotype have a 45,X karyotype, the rest either have a structurally abnormal X or Y chromosome or mosaicism with a second cell line. Determination of Y chromosome derivatives in patients with a 45,X karyotype is important for the management of these patients due to increased risk of gonadoblastoma. Low level mosaicism of Y chromosome may be missed by cytogenetic methods. The aim of our study is to analyze cryptic Y chromosome derivatives using Y specific sequences in 40 Turkish patients with a pure 45,X karyotype. Fourteen different Y specific sequences along the Y chromosome were selected for the detection of cryptic Y chromosome material by PCR analysis. The present study demonstrated that 2 patients with a 45,X karyotype (5%) have Y specific sequences except sex related region Y (SRY). One of them had displayed enhanced virilisation whereas other showed no virilisation. In conclusion, it has been found by PCR analysis that 5% of patients with a 45,X karyotype have Y chromosome sequences in the absence of any marker chromosome by cytogenetic analysis. The data also suggest that the patients with a 45,X karyotype should be analyzed for the presence of Y chromosome derivatives by sensitive methods, such as PCR, in order to calculate the future risk of developing gonadoblastoma.

Accurate diagnosis of a homozygous G1138A mutation in the fibroblast growth factor receptor 3 gene responsible for achondroplasia.

Achondroplasia is the most common genetic form of dwarfism inherited as an autosomal dominant disorder. Individuals affected with achondroplasia have impaired ability to form bone from cartilage (endochondral bone formation). Homozygous achondroplasia is a neonatal lethal condition. The vast majority of patients with achondroplasia have a G-to-A transition at position 1138 of the fibroblast growth factor receptor 3 (FGFR3) cDNA sequence, resulting in the Gly-to-Arg substitution at position 380 of the FGFR3 protein. This mutation has been diagnosed by SfcI digestion of amplified genomic DNA. However, it has also been demonstrated that the SfcI digestion protocol does not consistently distinguish between DNA samples heterozygous and homozygous for the G1138A substitution. This study was designed to improve the molecular diagnosis based on the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques for the FGFR3 G1138A mutation. The newly designed forward primer contains one mismatch (G at position 1136) from the FGFR3 cDNA sequence (A at position 1136), thereby creating a PstI site (CTGCAG at positions 1134 to 1139) in the amplified DNA from alleles containing the G1138A mutation. The PCR-RFLP technique based on the PstI digestion of amplified genomic DNA with a novel forward primer shows 100% accuracy in diagnosis of the G1138A mutation in heterozygous and homozygous individuals.

A case with proximal femoral focal deficiency (PFFD) and fibular A/hypoplasia (FA/H) associated with urogenital anomalies.

Malformations of the lower limbs are rare and heterogeneous anomalies. Some congenital anomalies involving face, gastrointestinal system, skeletal system, urogenital system, heart, lung and diaphragma associated with lower limb malformations have been described in the literature. Here, we report a case of left proximal femoral focal deficiency (PFFD) together with fibular aplasia associated with left undescended testis and hypospadias. The putative embryologic mechanisms of lower limb defects and their possible association with lower urogenital tract malformations are also discussed.

Partial trisomy 18q11.2-->qter due to de novo unbalanced translocation of chromosomes 15 and 18 analyzed by fluorescence in situ hybridization.

This report presents a case with partial trisomy 18q resulting from de novo unbalanced translocation of chromosomes 15 and 18 displaying the features of pure trisomy. This is the first reported case with partial trisomy 18q due to unbalanced translocation between chromosomes 15 and 18. Clinical findings of our case have been compared with the reported cases' had partial trisomy 18q and the importance to recognize the cases with chromosome abnormalities to give genetic counseling and prenatal diagnosis for subsequent pregnancies has emphasized.

Is it a new syndrome or a clinical variability in cerebro-oculo-nasal syndrome?

We present a male infant 2.5-months old with asymmetric skull, anophthalmia, apparent hypertelorism, abnormal nares, unilateral cleft lip and palate, and structural abnormalities of the central nervous system. These findings are similar to cerebro-oculo-nasal syndrome except for the appearance of nose. This case is either a clinical variability in cerebro-oculo-nasal syndrome or a new entity.

Cerebro-oculo-facio-skeletal syndrome: report of two cases from Turkey with postmortem findings.

We describe two cases of COFS (cerebro-oculo-facio-skeletal) syndrome in two newborn females of consanguineous parents. The clinical, radiological and pathological features of the patients are presented. One of the two cases had 11 pairs of ribs (Case 1) and the other had three-lobed left lung (Case 2), neither of which has been described in COFS syndrome previously. To our knowledge, these are the first reported cases of COFS syndrome from Turkey.