MED13L-related intellectual disability: involvement of missense variants and delineation of the phenotype.

Molecular anomalies in MED13L, leading to haploinsufficiency, have been reported in patients with moderate to severe intellectual disability (ID) and distinct facial features, with or without congenital heart defects. Phenotype of the patients was referred to "MED13L haploinsufficiency syndrome." Missense variants in MED13L were already previously described to cause the MED13L-related syndrome, but only in a limited number of patients. Here we report 36 patients with MED13L molecular anomaly, recruited through an international collaboration between centers of expertise for developmental anomalies. All patients presented with intellectual disability and severe language impairment. Hypotonia, ataxia, and recognizable facial gestalt were frequent findings, but not congenital heart defects. We identified seven de novo missense variations, in addition to protein-truncating variants and intragenic deletions. Missense variants clustered in two mutation hot-spots, i.e., exons 15-17 and 25-31. We found that patients carrying missense mutations had more frequently epilepsy and showed a more severe phenotype. This study ascertains missense variations in MED13L as a cause for MED13L-related intellectual disability and improves the clinical delineation of the condition.

ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome.

Chromosomal abnormalities are implicated in a substantial number of human developmental syndromes, but for many such disorders little is known about the causative genes. The recently described 1q41q42 microdeletion syndrome is characterized by characteristic dysmorphic features, intellectual disability and brain morphological abnormalities, but the precise genetic basis for these abnormalities remains unknown. Here, our detailed analysis of the genetic abnormalities of 1q41q42 microdeletion cases identified TP53BP2, which encodes apoptosis-stimulating protein of p53 2 (ASPP2), as a candidate gene for brain abnormalities. Consistent with this, Trp53bp2-deficient mice show dilation of lateral ventricles resembling the phenotype of 1q41q42 microdeletion patients. Trp53bp2 deficiency causes 100% neonatal lethality in the C57BL/6 background associated with a high incidence of neural tube defects and a range of developmental abnormalities such as congenital heart defects, coloboma, microphthalmia, urogenital and craniofacial abnormalities. Interestingly, abnormalities show a high degree of overlap with 1q41q42 microdeletion-associated abnormalities. These findings identify TP53BP2 as a strong candidate causative gene for central nervous system (CNS) defects in 1q41q42 microdeletion syndrome, and open new avenues for investigation of the mechanisms underlying CNS abnormalities.

A series of 38 novel germline and somatic mutations of NIPBL in Cornelia de Lange syndrome.

Cornelia de Lange syndrome is a multisystemic developmental disorder mainly related to de novo heterozygous NIPBL mutation. Recently, NIPBL somatic mosaicism has been highlighted through buccal cell DNA study in some patients with a negative molecular analysis on leukocyte DNA. Here, we present a series of 38 patients with a Cornelia de Lange syndrome related to a heterozygous NIPBL mutation identified by Sanger sequencing. The diagnosis was based on the following criteria: (i) intrauterine growth retardation and postnatal short stature, (ii) feeding difficulties and/or gastro-oesophageal reflux, (iii) microcephaly, (iv) intellectual disability, and (v) characteristic facial features. We identified 37 novel NIPBL mutations including 34 in leukocytes and 3 in buccal cells only. All mutations shown to have arisen de novo when parent blood samples were available. The present series confirms the difficulty in predicting the phenotype according to the NIPBL mutation. Until now, somatic mosaicism has been observed for 20 cases which do not seem to be consistently associated with a milder phenotype. Besides, several reports support a postzygotic event for those cases. Considering these elements, we recommend a first-line buccal cell DNA analysis in order to improve gene testing sensitivity in Cornelia de Lange syndrome and genetic counselling.

Imaging features of lower limb malformations above the foot.

Lower limb malformations are generally isolated or sporadic events. However, they are sometimes associated with other anomalies of the bones and/or viscera in patients with constitutional syndromes or disorders of the skeleton. This paper reviews the main imaging features of these abnormalities, which generally exhibit a broad spectrum. This paper focuses on several different bone malformations: proximal focal femoral deficiency, congenital short femur and femoral duplication for the femur, tibial hemimelia (aplasia/hypoplasia of the tibia) and congenital bowing for the tibia, fibular hemimelia (aplasia/hypoplasia) for the fibula, and aplasia, hypoplasia and congenital dislocation for the patella.

What can we learn from old microdeletion syndromes using array-CGH screening?

Most microdeletion syndromes identified before the implementation of array-comparative genomic hybridization (array-CGH) were presumed to be well-defined clinical entities. However, the introduction of whole-genome screening led not only to the description of new syndromes but also to the recognition of a broader spectrum of features for well-known syndromes. Here, we report on 10 patients presenting with mental retardation associated with atypical features not suggestive of a known microdeletion and a normal standard karyotype. Array-CGH analyses revealed five microdeletions in the DiGeorge region, three microdeletions in the Williams-Beuren region and two microdeletions in the Smith-Magenis region. Reevaluation in these patients confirmed that the diagnosis remained difficult on clinical grounds and emphasized that well-known genomic disorders can have a phenotype that is heterogeneous and more variable than originally thought. The widespread use of array-CGH shows that such patients may be more readily achieved on the basis of genotype rather than phenotype.

IRF6 Screening of Syndromic and a priori Non-Syndromic Cleft Lip and Palate Patients: Identification of a New Type of Minor VWS Sign.

Van der Woude syndrome (VWS), caused by dominant IRF6 mutation, is the most common cleft syndrome. In 15% of the patients, lip pits are absent and the phenotype mimics isolated clefts. Therefore, we hypothesized that some of the families classified as having non-syndromic inherited cleft lip and palate could have an IRF6 mutation. We screened in total 170 patients with cleft lip with or without cleft palate (CL/P): 75 were syndromic and 95 were a priori part of multiplex non-syndromic families. A mutation was identified in 62.7 and 3.3% of the patients, respectively. In one of the 95 a priori non-syndromic families with an autosomal dominant inheritance (family B), new insights into the family history revealed the presence, at birth, of lower lip pits in two members and the diagnosis was revised as VWS. A novel lower lip sign was observed in one individual in this family. Interestingly, a similar lower lip sign was also observed in one individual from a 2nd family (family A). This consists of 2 nodules below the lower lip on the external side. In a 3rd multiplex family (family C), a de novo mutation was identified in an a priori non-syndromic CL/P patient. Re-examination after mutation screening revealed the presence of a tiny pit-looking lesion on the inner side of the lower lip leading to a revised diagnosis of VWS. On the basis of this data, we conclude that IRF6 should be screened when any doubt rises about the normality of the lower lip and also if a non-syndromic cleft lip patient (with or without cleft palate) has a family history suggestive of autosomal dominant inheritance.

[Prenatal diagnosis of hyperechogenic kidneys: A study of 17 cases]. / Diagnostic anténatal des reins hyperéchogènes : à propos de 17 cas.

OBJECTIVES: To evaluate the prenatal diagnosis and the prognostic value of ultrasound in case of fetal hyperechogenic kidneys. PATIENTS AND METHODS: Seventeen prenatally diagnosed cases of hyperechogenic kidneys were retrospectively reviewed at the University Hospital of Lille from 1997 to 2008. The clinical and ultrasound data were compared to the postnatal follow-up and the long-term prognosis. RESULTS: The aetiologies are nine recessive polycystic kidney diseases, three dominant, two Bardet-Biedl syndromes and three cases of transient renal hyperechogenicity. No renal ultrasonographic criterion is specific of aetiology. Five pregnancies were terminated. We observed one neonatal death and 11 survivors (median follow-up: 30months) including two infants with hypertension. All oligohydramnios (n=8) were associated with poor prenatal outcomes (terminations of pregnancy, neonatal death or hypertension) compared to the other nine with normal amniotic fluid volume (nine children symptom-free). Kidneys less or equal to +4 S.D. and a normal amniotic fluid volume were associated with a good prognosis (n=7, seven symptom-free). CONCLUSION: The fetal kidneys characteristics on prenatal ultrasound fail to provide an accurate etiological diagnosis. Only congenital defects and family history adjust the aetiology. Amniotic fluid volume and fetal kidney size are the best prenatal predictors of outcome.

Bilateral periventricular nodular heterotopia in France: frequency of mutations in FLNA, phenotypic heterogeneity and spectrum of mutations.

Bilateral periventricular nodular heterotopia (BPNH) is the most common form of periventricular heterotopia. Mutations in FLNA, encoding filamin A, are responsible for the X linked dominant form of BPNH (FLNA-BPNH). Recently, atypical phenotypes including BPNH with Ehlers-Danlos syndrome (BPNH-EDS) have been recognised. A total of 44 FLNA mutations have so far been reported in this phenotype. Most of these mutations lead to a truncated protein, but few missense mutations have also been described. Here, the results of a mutation screening conducted in a series of 32 BPNH patients with the identification of 12 novel point mutations in 15 patients are reported. Nine mutations were truncating, while three were missense. Three additional patients with BPNH-EDS and a mutation in FLNA are described. No phenotype-genotype correlations could be established, but these clinical data sustain the importance of cardiovascular monitoring in FLNA-BPNH patients.

[Genetics and orthopedics: genetic implications of congenital limb abnormalities]. / Génétique et orthopédie: gènes impliqués dans les malformations congénitales des membres.

Limb malformations are frequent. These malformations are isolated or associated with anomalies of other developmental fields and accurate diagnostic is essential for prognosis evaluation, treatment and genetic counseling. Animal embryology and molecular biology techniques, have given us a better understanding of the processes of growth and patterning of the limb buds. The key genes that are involved in these processes have been identified and their interactions recognized. Human genetics has been able to identify, or at least localize, several genes implicated in limb development. We here review the present knowledge on these genes and their mutations responsible for limb anomalies.

[Fatal neonatal respiratory distress in Niemann-Pick C2 and prenatal diagnosis with mutations in gene HE1/NPC2]. / Forme respiratoire néonatale létale de la maladie de Niemann-Pick C2 et diagnostic anténatal par l'étude des mutations du gène HE1/NPC2.

UNLABELLED: We report the fifth case of neonatal form of type C2 (NP-C2) Niemann-Pick disease with early and fatal respiratory distress. Eleven families presenting such cases are known to date in the world. Since December 2000, isolation of the underlying gene HE1/NPC2 and its mutations has allowed major advances in diagnosis. CASE REPORT: Elisa was born in May 2000. NP-C2 disease was associated with severe respiratory distress leading to death at the age of four months. On the next pregnancy in September 2000, prenatal diagnosis was performed by means of biological tests that required four weeks response time. In December 2000, isolation of the HE1/NPC2 gene located to 14q24.3 and of some of its mutations allowed to characterize the patient as being homozygote for the nonsense mutation E20X. On the the two next pregnancies, prenatal diagnosis was performed at 12 SA, in 48 hours, by the means of mutation analysis. The last fetus was heterozygote for the mutation E20X, allowing the birth at term of a healthy male newborn baby. CONCLUSION: Niemann-Pick type C disease is a rare lysosomal lipid storage disease with severe prognosis. It is characterized by abnormalities of intracellular transport of endocytosed cholesterol. Diagnosis relies on biological tests that require cultured cells. Genetic heterogeneity defines two different genetic complementation groups C1 and C2. Severe and early respiratory distress is more likely to be associated with the rare type C2. Since December 2000, after identification of the disease-causing mutations in the proband, mutation analysis of gene HE1/NPC2 on direct chorionic villus samples allows early and fast (48 hours) prenatal diagnosis.

[Dyggve-Melchior-Clausen syndrome: differential diagnosis of mucopolysaccharidosis type IV or Morquio disease]. / Le syndrome de Dyggve-Melchior-Clausen: diagnostic différentiel de la mucopolysaccharidose de type IV ou maladie de Morquio.

UNLABELLED: Dyggve-Melchior-Clausen syndrome (DMCS) is an autosomal recessive skeletal dysplasia. Clinical and radiological similarities with Morquio's syndrome can initially lead wrongly to this diagnosis. CASE REPORT: A nine-year-old boy had mental retardation and progressive postnatal dwarfism. Platyspondyly and dysplastic epiphyses and metaphyses resembled those of Morquio's disease; however, clinical and radiological data led to the diagnosis of DMCS. CONCLUSION: Clinical and paraclinical features allowing the differentiation of Morquio's syndrome and DMCS are discussed. Initial clinical presentation may be similar, but the intellectual prognosis is different.

Radioulnar synostosis, radial ray abnormalities, and severe malformations in the male: a new X-linked dominant multiple congenital anomalies syndrome?

We describe a multiple congenital anomalies (MCA) syndrome dominantly transmitted through three generations. Radial ray abnormalities with wide variability of expression were observed in four female patients. Moreover, a 14-week-gestation male fetus had severe radial ray malformation, anencephaly, unilateral renal agenesis, and a common dorsal mesentery. Results of high-resolution karyotyping were normal in the malformed fetus and his affected mother. Furthermore, several spontaneous abortions of male fetuses had occurred in this pedigree. To our knowledge, a similar association has not been described previously. It could represent a new X-linked dominant MCA syndrome, or an autosomal dominant condition with severe expression limited to males.

The Richieri-Costa and Pereira form of acrofacial dysostosis: first case in a non-Brazilian infant.

We report on a French boy with cleft mandible, pre/postaxial hand anomalies, and clubfoot born to consanguineous parents. These findings are comparable to those of previous cases of the autosomal recessive Richieri-Costa and Pereira syndrome of short stature, Robin sequence, cleft mandible, pre/postaxial hand anomalies, and clubfoot. This is the first case in a non-Brazilian infant.

Unreported RSK2 missense mutation in two male sibs with an unusually mild form of Coffin-Lowry syndrome.

An unreported missense mutation of the ribosomal S6 kinase 2 (RSK2) gene has been identified in two male sibs with a mild form of Coffin-Lowry syndrome (CLS) inherited from their healthy mother. They exhibit transient severe hypotonia, macrocephaly, delay in closure of the fontanelles, normal gait, and mild mental retardation, associated in the first sib with transient autistic behaviour. Some dysmorphic features of CLS (in particular forearm fullness and tapering fingers) and many atypical findings (some of which were reminiscent of FG syndrome) were observed as well. The moderate phenotypic expression of this mutation extends the CLS phenotype to include less severe mental retardation and minor, hitherto unreported signs. The missense mutation identified may be less deleterious than those previously described. As this mutation occurs in a protein domain with no predicted function, it could be responsible for a conformational change affecting the protein catalytic function, since a non-polar amino acid is replaced by a charged residue.