Jürgen Kohlhase

Sall1, Sall2, and Sall4 Are Required for Neural Tube Closure in Mice

Four homologs to the Drosophila homeotic gene spalt (sal) exist in both humans and mice (SALL1 to SALL4/Sall1 to Sall4, respectively). Mutations in both SALL1 and SALL4 result in the autosomal-dominant developmental disorders Townes-Brocks and Okihiro syndrome, respectively. In contrast, no human diseases have been associated with SALL2 to date, and Sall2-deficient mice have shown no apparent abnormal phenotype. We generated mice deficient in Sall2 and, contrary to previous reports, 11% of our Sall2-deficient mice showed background-specific neural tube defects, suggesting that Sall2 has a role in neurogenesis. To investigate whether Sall4 may compensate for the absence of Sall2, we generated compound Sall2 knockout/Sall4 genetrap mutant mice. In these mutants, the incidence of neural tube defects was significantly increased. Furthermore, we found a similar phenotype in compound Sall1/4 mutant mice, and in vitro studies showed that SALL1, SALL2, and SALL4 all co-localized in the nucleus. We therefore suggest a fundamental and redundant function of the Sall proteins in murine neurulation, with the heterozygous loss of a particular SALL protein also possibly compensated in humans during development.

Dystrophic epidermolysis bullosa pruriginosa is not associated with frequent FLG gene mutations

Background  Dystrophic epidermolysis bullosa pruriginosa (DEB‐Pr; OMIM 604129) is a rare manifestation of dystrophic epidermolysis bullosa (DEB), characterized by pruritus, nodular prurigo‐like lesions and fragility of the skin mainly in the extremities. Fewer than 40 patients with autosomal dominant or recessive inheritance, or sporadic DEB‐Pr, have been described in the literature.

Sall4 isoforms act during proximal-distal and anterior-posterior axis formation in the mouse embryo

Reciprocal signals from embryonic and extra‐embryonic tissues pattern the embryo in proximal–distal (PD) and anterior–posterior (AP) fashion. Here we have analyzed three gene trap mutations of Sall4, of which one (Sall4‐1a) led to a hypomorphic and recessive phenotype, demonstrating that Sall4‐1a has yet undescribed extra‐embryonic and embryonic functions in regulating PD and AP axis formation. In Sall4‐1a mutants the self‐maintaining autoregulatory interaction between Bmp4, Nodal and Wnt, which determines the PD axis was disrupted because of defects in the extra‐embryonic visceral endoderm. More severely, two distinct Sall4 gene‐trap mutants (Sall4‐1a,b), resembling null mutants, failed to initiate Bmp4 expression in the extra‐embryonic ectoderm and Nodal in the epiblast and were therefore unable to initiate PD axis formation. Tetraploid rescue underlined the extra‐embryonic nature of the Sall4‐1a phenotype and revealed a further embryonic function in Wnt/β‐catenin signaling to elongate the AP axis during gastrulation. This observation was supported through genetic interaction with β‐catenin mutants, since compound heterozygous mutants recapitulated the defects of Wnt3a mutants in posterior development. genesis 46:463–477, 2008.

Esophageal atresia, hypoplasia of zygomatic complex, microcephaly, cup‐shaped ears, congenital heart defect, and mental retardation—New MCA/MR syndrome in two affected sibs and a mildly affected mother?

The previously undescribed combination of esophageal atresia, hypoplasia of the zygomatic complex, microcephaly, cup‐shaped ears, congenital heart defect, and mental retardation was diagnosed in two siblings of different sexes, with the brother being more severely affected. The mother presented with zygomatic arch hypoplasia of the right side only. We discuss major differential diagnoses: Goldenhar, Feingold, CHARGE, and Treacher Collins syndromes show a few overlapping clinical features, but these diagnoses are unlikely as the clinical findings are unusual for Goldenhar syndrome and mutational screening of the MYCN, the CHD7, and the TCOF1 genes did not reveal any abnormalities. Autosomal recessive oto–facial syndrome, hypomandibular faciocranial dysostosis, and Ozkan syndromes were clinically excluded. A microdeletion 22q11.2 was excluded by FISH analysis, a microdeletion 2p23‐p24 by microsatellite analyses, a subtelomeric chromosomal aberration by MLPA, and a small genomic deletion/duplication by CGH array. As X‐inactivation studies did not show skewed X‐inactivation in the mother, we consider X‐chromosomal recessive inheritance of this condition less likely. We discuss autosomal dominant inheritance with variable expressivity or mosaicism in the mother as the likely genetic mechanism in this new multiple congenital anomaly/mental retardation (MCA/MR) syndrome.

Late-onset inversa recessive dystrophic epidermolysis bullosa caused by glycine substitutions in collagen type VII

Dystrophic epidermolysis bullosa (DEB) is a rare hereditary skin disorder caused by mutations in COL7A1, encoding collagen type VII.1 Clinical manifestations of COL7A1 mutations range from generalized skin blistering to mild localized blistering or nail dystrophy.2 The investigation of the molecular basis of DEB has revealed more than 540 different mutations that cannot entirely explain phenotypic variations (HGMD Professional 2010.3, https://portal.biobase-international. com/hgmd/). Inversa recessive DEB (RDEB-I) is a subtype characterized by generalized blistering in the neonatal period. The condition improves with age, and in adults blistering is restricted to intertriginous areas, and severe lesions of the oral and genital mucosa and nail changes occur in the majority of described patients.2 Recent data suggested that amino-acid substitutions affecting arginines or glycines at borders of collagenic subdomains might cause this phenotype.3 We report a German patient with an unusually mild RDEB-I harbouring compound heterozygous mutations in COL7A1.

Pilomatricomas in Rubinstein-Taybi syndrome

Pilomatricomas are quite rare, benign epithelial neoplasms of follicular cell derivation. The most common sites are the head and neck, less frequently the arms and trunk. Most pilomatricomas arise either between 2 to 15 years or 45 to 65 years of age. They occur mostly in female gender and present clinically as firm, well-circumscribed, 0.5–5 cm, skincolored or erythematous, dermal or subcutaneous nodules. Inflammation or erosion through the skin surface (perforating variant) are rare. Of importance for the clinician is the association of multiple pilomatricomas with Rubinstein-Taybi (Table 1), Gardner, and Turner syndromes as well as trisomy 9 and myotonic dystrophy (which is caused by a mutation in the dystrophia myotonica protein kinase [DMPK] gene) [1–5]. In September 2012, a 49-year-old woman was admitted to our clinic for excision of a pedunculated cutaneous horn on the scalp. The patient was affected by diabetes mellitus type II, arterial hypertension, glaucoma and intellectual disability/developmental delay since birth, attributed to an early childhood brain injury. She was on multiple routine medications for her underlying diseases. A 2 x 5 cm pedunculated friable cutaneous horn was present on the right parietal region (Figure 1a). Furthermore, keloids secondary to skin tumor removal in childhood were found on the left retroauricular area, left shoulder and upper chest (Figure 1b). The patient also showed a nevus flammeus on the nose, microcephaly, heavy arched eyebrows and long eye-lashes, prominent forehead, hypertelorism and strabismus. Her nose was beaked with a broad fleshy bridge with the nasal septum extending below the alae nasi. She also was showing signs of retrognathism and she had a small mouth, a highly arched palate, crowded irregular teeth and hirsutism (Figure 1d, e). Her thumbs and big toes were disproportionally broad (Figure 1c). She had a stiff gait as well as a tendency to constipation and infections. Dermatopathology of the scalp lesion showed an irregular, but sharply defined multilobular tumor, with masses of shadow cells and keratin, accompanied by inflammation consisting of lymphocytes and multinucleated giant cells (Figure 1f). The tumor was classified as a secondary inflamed pilomatricoma (epithelioma calcificans Malherbe). The clinical features and symptoms led us to suspect Rubinstein-Taybi syndrome. Molecular genetic testing by PCR and direct DNA sequencing revealed the mutation c.6127C>T, p.Q2043*, in exon 31 of the CREBBP gene in a heterozygous state (Figure 1g). Rubinstein-Taybi syndrome is a multisystem developmental disorder and is clinically defined by a moderate to severe intellectual disability, broad thumbs and halluces and characteristic facial features, including heavy arched eyebrows and long lashes, downslant of the palpebral fissures, epicanthal folds, a prominent beaked nose with long columella, protruding below the level of the nasal alae, and in some cases a deviated septum, retrognathism, microstomia and low-set angulated ears with thickened helices [6–8]. Important dermatological findings include hemangiomas, hypertrichosis, keloids, supernumerary nipple, unusual dermatoglyphics and a predisposition to developing pilomatricomas. [1–4] The patients often have a tendency towards constipation, recurrent

New Recognized Ophthalmic Morphologic Anomalies in CHARGE Syndrome Caused by the R2319C Mutation in the CHD7 Gene

Purpose: To report new findings in the CHARGE syndrome with phenotypic anomalies associated with the R2319C mutation in the CHD7 gene. Methods: Fundoscopic photography, ultrasonography, fluorescein angiography, optical coherence tomography (OCT). Mutational analysis of the CHD7 gene in lymphocyte DNA. Results: Large pale optic discs with a fibrous elevation and colobomata and arterio-venous anastomoses with enlarged veins in optic discs were detected. OCT revealed numerous flat cystic spaces. The genetic study revealed the R2319C mutation in the CHD7 gene. Conclusions: The CHARGE syndrome associated with the R2319C mutation in the CHD7 gene comprised: cystic spaces in the colobomatous optic disc and intrapapillary arterio-venous anastomoses.

Feingold syndrome associated with two novel MYCN mutations in sporadic and familial cases including monozygotic twins

Feingold syndrome is a developmental disorder with considerable phenotypic variability [Courtens et al., 1997; Feingold et al., 1997; Buttiker et al., 2000; Herman and Siegel, 2004; Holder-Espinasse et al., 2004; van Bokhoven et al., 2005; Teszas et al., 2006]. Major characteristic features are microcephaly, typical malformations of hands and feet (clinodactyly of 2nd and 5th fingers, and syndactyly 4–5 of toes), and duodenal or esophageal atresia. Cardiac and renal malformations, vertebral anomalies, imperforate anus, and deafness are less frequent. Feingold syndrome is caused by mutations in the MYCN gene, leading to haploinsufficiency [van Bokhoven et al., 2005]. Fourteen different mutations have been described, 12 of which were found in exon 3 [van Bokhoven et al., 2005; Teszas et al., 2006; Layman-Pleet et al., 2007]. MYCN consists of three exons with the ATG for the canonical protein (the most commonly referred isoform encoded by exons 2 and 3) located in exon 2. Initially, no mutations were found in exon 2. To explain this observation, van Bokhoven et al. offered the hypothesis that mutations in exon 2 would only affect the transcript containing exon 2, whereas the transcript consisting of exons 1 and 3 would not be affected. This hypothesis would also imply that exon 2 might not encode domains as important for development as those encoded by exon 3 [van Bokhoven et al., 2005]. Recently, the first mutation was detected in exon 2 [Teszas et al., 2006]. In this family, a boy was affected with esophageal atresia, microcephaly, clinodactyly of his 5th fingers, and absent middle phalanges of the second and third toes, as well as significant developmental delay. The mother and the maternal grandmother of the boy also had the same non-sense mutation in exon 2, but with a milder phenotype referred to as ‘‘microcephaly digital anomalies-normal intelligence syndrome’’ (OMIM#602585). Another case with an exon 2 non-sense mutation was recently reported [Layman-Pleet et al., 2007]. This boy had esophageal atresia with tracheo-esophageal fistula, a dysplastic right kidney, microcephaly, and bilateral hypoplasia of the 5th fingers with clinodactyly as well as some dysmorphic facial features. His mother also carried the Trp77Stop (p.W77X) mutation, but she was affected only with similar digital anomalies and a head size corresponding to the 10th centile. Since these are the only exon 2 mutations currently reported, it remained questionable what phenotypic range will be associated with such molecular defects. Here we report on two novel mutations in MYCN. The first one is a de novo frameshift mutation in exon 2 in a sporadic case of Feingold syndrome, and the second is a novel heterozygous missense mutation in exon 3 in a familial case, first found in a pair of monozygotic twins. Patient 1: The proposita is the first of two daughters of healthy, no consanguineous parents of Turkish origin. At birth the mother was 34 years old and the father was 31 years old. The pregnancy was

New mutation leading to the full variety of typical features of the Netherton syndrome.

Netherton syndrome is a rare autosomal recessive inherited disease with an incidence of 1 / 200 000, first described by Comel in 1949 and by Netherton in 1959 [1–3]. The characteristic symptoms are ichthyosis linearis circumflexa, trichorrhexis invaginata, an elevated susceptibility to recurrent infections and an allergic diathesis. We report a female patient showing the typical features of Netherton syndrome caused by compound heterozygous mutations of SPINK5 gene one of which being unknown. A 23-year-old woman presented with widespread pruritic erythematous, serpiginous skin eruptions with double-edged scales at the periphery. Her skin was very dry with flexural lichenification, while eyebrows and eyelashes were sparse (Figure 1a). Her hair was fragile and easy to break. A chronic cystitis was present with therapy-resistant vaginal discharge. The generalized erythroderma with exfoliative scaling started on the second day of her life. Past medical history revealed allergic rhinitis and asthma as well as allergic reactions to banana, apple, kiwi and nut. Family history was significant for her mother having asthma and a nickel allergy. Her father and brother are healthy. On the basis of clinical findings the diagnosis of Netherton syndrome had already been made in childhood. Laboratory blood tests were normal except for elevated IgE levels (1 373 kU/l). Skin tests were positive to grass, birch, alder, osier, mugwort, acarid, rye and hazel pollen. Histopathology revealed changes resembling a chronic dermatitis (Figure 2). Microscopic analysis of the hair shaft showed typical „bamboo hairs“ of trichorrhexis invaginata with invaginated nodules (Figure 1b). The analysis of the SPINK5 gene (NM_001127698.1, NC_000005.9) reveals a heterozygous mutation c.316_317delGA, p.D106Wfs*7 in Exon 5 and c.2468dupA, p.K824Efs*4 in Exon 26. Both mutations generate a premature stop codon. Analysis of the SPINK5 gene of the parents shows a heterozygous mutation in c.316_317delGA, p.D106Wfs*7, in Exon 5 by the father and a heterozygous mutation c.2468dupA, p.K824Efs*4 in Exon 26 of the mother. The mutation c.316_317delGA, p.D106Wfs*7, in Exon 5 has never been described before and therefore represents a novel deletion mutation contributing to Netherton syndrome. Clinical Letter

Eine neue Mutation führt zum gesamten Spektrum der typischen Merkmale des Netherton-Syndroms

das Netherton-Syndrom ist eine seltene, autosomal-rezessiv vererbte Krankheit mit einer Inzidenz von 1/200 000, die erstmals von Comel im Jahr 1949 sowie von Netherton im Jahr 1959 beschrieben wurde [1–3]. Ihre charakteristischen Symptome sind Ichthyosis linearis circumflexa, Trichorrhexis invaginata, erhöhte Anfälligkeit gegenüber rezidivierenden Infekten und allergische Diathese. Wir berichten hier über eine Patientin mit den typischen Merkmalen des Netherton-Syndroms, die durch compound-heterozygote Mutationen des SPINK5-Gens verursacht werden, von welchen eine unbekannt ist. Eine 23-jährige Patientin stellte sich vor mit ausgedehntem pruritischem, erythematösem, serpinginösem Exanthem mit doppelrandigen Schuppen an der Peripherie. Ihre Haut war sehr trocken und wies Lichenifikation in den Gelenkbeugen auf. Ihre Augenbrauen und Wimpern waren spärlich ausgebildet (Abbildung 1a), ihre Haare waren dünn und brüchig. Außerdem lag eine chronische Cystitis mit therapieresistentem vaginalem Ausfluss vor. Generalisierte Erythrodermie mit exfoliativer Schuppung zeigte sich bereits an ihrem zweiten Lebenstag. Die Anamnese ergab allergische Rhinitis und Asthma sowie allergische Reaktionen auf Bananen, Äpfel, Kiwi und Nüsse. Die Familienanamnese war insofern relevant, als ihre Mutter an Asthma und einer Nickelallergie leidet, ihr Vater und ihr Bruder sind dagegen gesund. Auf der Grundlage der klinischen Befunde war die Diagnose Netherton-Syndrom bereits in der Kindheit gestellt worden. Die Laborwerte waren unauffällig, abgesehen von einem erhöhten IgE-Spiegel (1373 kU/l). Der Hauttest war positiv für Gräser-, Birken-, Erlen-, Korbweiden-, Beifuß-, Roggenpollen und Haselnusspollen. Bei der Histopathologie wurden Veränderungen nachgewiesen, die denen einer chronischen Dermatitis ähnelten (Abbildung 2). Die mikroskopische Untersuchung der Haarschäfte zeigte die typischen „Bambushaare“ einer Trichorrhexis invaginata mit eingestülpten Knoten (Abbildung 1b). Die Analyse des SPINK5-Gens Clinical Letter