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.

Amniotic band syndrome is an uncommon congenital pathological condition that may lead to malformations and foetal-infant death. We report an autoptic case. The patient was a male preterm infant. At 14 weeks of gestation, a routine ultrasonography showed severe craniofacial anomalies and a close contiguity of the foetal head with the amnios. The neonate survived three days, after which an autopsy was carried out. The infant had a frontoparietal meningoencephalocele; a fibrous band was attached to the skin, close to the meningoencephalocele base. Cleft lip and palate, nose deformation and agenesis of the right eye were also present. At the opening of the cranial cavity, occipital hyperostosis was observed. The herniated brain showed anatomical abnormalities that made identification of normal structures difficult. Microscopically, the nervous parenchyma had architectural disorganization and immaturity, and the fibrous band consisted of amniotic membranes. As evident from this case report, amniotic band syndrome may cause severe malformations and foetal-infant death.

Anhidrotic/hypohidrotic ectodermal dysplasia is a rare disorder, genetically heterogeneous, commonly X-linked recessive inherited, characterized by hypoplasia up to the absence of the eccrine glands with hypo-anhidrosis and secondary hyperpyrexia, hypodontia and some typical craniofacial features. Some papers have described how these patients may show poor growth, while other recent research shows normal growth. We report a boy with anhidrotic/hypohidrotic ectodermal dysplasia and growth hormone neurosecretory dysfunction, an association not previously reported, and we discuss the possible causes as well as the patient's response to growth hormone treatment until he reached final height.

We describe a patient with the clinical spectrum of Young-Simpson syndrome. This rare genetic disorder is characterized by congenital hypothyroidism, mental retardation and blephar-ophimosis. Young-Simpson syndrome is, at present, poorly known to endocrinologists and pediatricians, and should be included in the differential diagnosis of congenital hypothyroidism. It is important to underline that the association of congenital hypothyroidism, blepharophimosis and ptosis allows an exact clinical diagnosis, since the majority of other clinical aspects are common to other disorders.

Craniofrontonasal syndrome (CFNS [MIM 304110]) is an X‐linked malformation syndrome characterized by craniofrontonasal dysplasia and extracranial manifestations in heterozygous females. In the majority of patients CFNS is caused by mutations in the EFNB1 gene (MIM 300035). We identified three girls with classical CFNS and mild developmental delay harboring de novo deletions of the EFNB1 gene. Applying haplotype analysis, Southern blot hybridization and array‐comparative genomic hybridization, deletion of EFNB1 was found to be part of contiguous gene deletions in the patients. In one patient the deletion interval includes the genes for oligophrenin‐1 (OPHN1 [MIM 300127]) and praja 1 (PJA1 [MIM 300420]). In the second patient the deletion includes OPHN1, PJA1 and the gene for ectodysplasin A (EDA [MIM 300451]). In the third patient EFNB1 gene deletion may include deletion of regulatory regions 5′ of OPHN1. Previously, the OPHN1 gene has been shown to be responsible for recessive X‐linked mental retardation. Although it is too early to predict the future cognitive performance of the two infant patients with contiguous gene deletions of OPHN1–EFNB1–PJA1, mild learning disabilities have been recognized in the older, third patient. It is important for genetic counseling to be aware that their male offspring may not only be carriers of CFNS but may also be affected by mental retardation and anhidrotic ectodermal dysplasia.

Human Monozygotic (MZ) Twins estimated to occur once in 250 live births, result from an abnormal behavior by embryonic cell(s) to develop as separate embryos. The MZ twins are considered genetically identical and the reduced phenotypic, genetic or chromosomal concordance represents a very important challenge for geneticists. Determination of zygosity by molecular studies usefully provides a superior replacement for the conventional studies of placenta and chorionic membranes. We utilized a protocol based on the CODIS polymorphic markers battery, by using an infrared LI-COR 4200 instrument (LICOR, Nebraska, USA), and we associated the statistical analysis method with formulae derived by the DNA-View's Kinship Module to better evaluate the genetic identity in a group of MZ twins. (C) 2003 Elsevier B.V. All rights reserved.

Williams syndrome is a well-recognized disorder, having an incidence of 1 in 20,000 live births. However, thyroid function in these patients is rarely studied. This paper reports thyroid hypoplasia of the left lobe in two girls affected by Williams syndrome, suggesting that it may be a feature of this syndrome.

We report on the cytogenetic, fluorescence in situ hybridization (FISH), and molecular results obtained for a patient with a mild and nonspecific pattern of minor anomalies and developmental delay. In the proband's karyotype one chromosome 18 was replaced by a ring chromosome 18 in all metaphases, with deletion of the terminal regions. Furthermore, 56% of the metaphases contained a supernumerary small ring chromosome. Microdissection followed by FISH analysis demonstrated that the small ring chromosome consisted of material from the pericentromeric region of chromosome 18. The karyotype was defined as 46,XX,r(18)(p11.3q23)[88]/47,XX,r(18)(p11.3q23)+r(18)(p11.22q12.2)[112]. Thus, the patient has a deletion at 18pter and at 18qter, and a mosaic partial trisomy of the pericentromeric region of chromosome 18. We undertook molecular analysis using DNA samples of the patient and her parents in order to clarify the origin and possible mode of formation of the chromosome abnormalities. Our results show a paternal origin of the structurally normal chromosome 18 and a maternal origin for both ring chromosomes 18. Interestingly, the smaller ring chromosome did not arise postzygotically from the larger ring, since the two ring chromosomes contain genetic material derived from the two different maternal chromosomes 18. The abnormalities appear to have arisen during a meiotic division, and it could be speculated that both ring chromosomes 18 arose simultaneously due to complex pairing and recombination events. After fertilization, the small ring chromosome was lost in a subset of cells, thus leading to mosaicism.

We report a direct DNA sequencing analysis of the MECP2 gene undertaken on a further 64 Italian patients with Rett syndrome by using a LICOR 4200 Automated Sequencer. All of the girls entering the study had a consistent clinical diagnosis for this disorder. All coding regions and the flanking intronic splice site sequences were amplified as three non-overlapping fragments by using both forward and reverse primers. The results were then compared to the MECP2 reference sequences published in GenBank. Mutations of the MECP2 gene were identified in 64 of 75 (85.33%) unrelated sporadic Rett syndrome girls. Genotype/phenotype correlation studies, in particular in groups of patients with the same mutation, did not offer definitive and interesting data.

Exclusion or confirmation of incest as the cause of Mendelian disorders was performed on three families, in our laboratories, by using a set of STRs DNA markers. In the first family, the father/daughter incest was confirmed; in the same time, due to the mechanism of genetic transmission, the incest was excluded to be the cause of the X-linked MR alpha-Thalassaemia syndrome, observed in the child. In the second family, the father/daughter incest was confirmed, and also related to the Cystic Fibrosis in the child. In the third family, a father/daughter incest, presumed to be the cause of a genetic disorder (Escobar Syndrome), transmitted as Autosomal Recessive character, in two sisters, was excluded.