The Brachmann-de Lange syndrome in two siblings of normal parents

Germline mosaicism in Cornelia de Lange syndrome

Cornelia de Lange syndrome (CdLS) is a genetic disorder associated with delayed growth, intellectual disability, limb reduction defects, and characteristic facial features. Germline mosaicism has been a described mechanism for CdLS when there are several affected offspring of apparently unaffected parents. Presently, the recurrence risk for CdLS has been estimated to be as high as 1.5%; however, this figure may be an underrepresentation. We report on the molecularly defined germline mosaicism cases from a large CdLS database, representing the first large case series on germline mosaicism in CdLS. Of the 12 families, eight have been previously described; however, four have not. No one specific gene mutation, either in the NIPBL or the SMC1A gene, was associated with an increased risk for germline mosaicism. Suspected or confirmed cases of germline mosaicism in our database range from a conservative 3.4% up to 5.4% of our total cohort. In conclusion, the potential reproductive recurrence risk due to germline mosiacism should be addressed in prenatal counseling for all families who have had a previously affected pregnancy or child with CdLS.

Paternal gonadal mosaicism of NIPBL mutation in a father of siblings with Cornelia de Lange syndrome

OBJECTIVES

We report two siblings, a boy and a girl, with Cornelia de Lange syndrome (CdLS), born to unaffected parents, and attempt to delineate the underlying molecular mechanism leading to familial recurrence.

METHODS

Nipped-B-like (NIPBL) gene mutations were screened using in denaturing high-performance liquid chromatography and sequencing in peripheral blood samples, from one of the affected siblings and her parents, as well as from a sperm sample from the father.

RESULTS

A heterozygous missense NIPBL mutation, D2433G, was identified in the peripheral blood sample of the affected girl, but not in the peripheral blood samples of her parents. The D2433G mutation was also found in the sperm sample of the father.

CONCLUSION

Gonadal mosaicism represents an underappreciated feature of the inheritance pattern of CdLS. To our knowledge, the girl represents the first CdLS patient whose father was documented to have a population of mutant sperm. When a sperm analysis indicates the presence of a mutant allele, it may be reasonable to offer prenatal genetic testing to the family in subsequent pregnancies, given that the sensitivity of fetal ultrasonography is relatively low.

NIPBL mutational analysis in 120 individuals with Cornelia de Lange syndrome and evaluation of genotype-phenotype correlations

The Cornelia de Lange syndrome (CdLS) is a multisystem developmental disorder characterized by facial dysmorphia, upper-extremity malformations, hirsutism, cardiac defects, growth and cognitive retardation, and gastrointestinal abnormalities. Both missense and protein-truncating mutations in NIPBL, the human homolog of the Drosophila melanogaster Nipped-B gene, have recently been reported to cause CdLS. The function of NIPBL in mammals is unknown. The Drosophila Nipped-B protein facilitates long-range enhancer-promoter interactions and plays a role in Notch signaling and other developmental pathways, as well as being involved in mitotic sister-chromatid cohesion. We report the spectrum and distribution of NIPBL mutations in a large well-characterized cohort of individuals with CdLS. Mutations were found in 56 (47%) of 120 unrelated individuals with sporadic or familial CdLS. Statistically significant phenotypic differences between mutation-positive and mutation-negative individuals were identified. Analysis also suggested a trend toward a milder phenotype in individuals with missense mutations than in those with other types of mutations.

Dominant paternal transmission of Cornelia de Lange syndrome: a new case and review of 25 previously reported familial recurrences

The Cornelia de Lange syndrome (CdLS) is an autosomal dominant multisystem disorder characterized by somatic and cognitive retardation, characteristic facial features, limb abnormalities, hearing loss, and other organ system involvement. The vast majority of cases (99%) are sporadic, with rare familial occurrences having been reported. Most individuals with CdLS do not reproduce as a result of the severity of the disorder. Maternal transmission has been well documented, as have several cases of multiple-affected children being born to apparently unaffected parents. Paternal transmission has rarely been reported. A case is reported here of a father with classic features of CdLS with a similarly affected daughter. A review of the reported familial cases of CdLS is summarized.

De Lange syndrome: subjective and objective comparison of the classical and mild phenotypes

Classical de Lange syndrome presents with a striking face, pronounced growth and mental retardation, and variable limb deficiencies. Over the past five years, a mild variant has been defined, with less significant psychomotor retardation, less marked pre- and postnatal growth deficiency, and an uncommon association with major malformations, although mild limb anomalies may be present. We have evaluated 43 subjects with de Lange syndrome, 30 with classical features, aged from birth to 21 years, and 13 with the mild phenotype, aged from 18 months to 30 years. In addition to assessment of gestalt and facial change with time, detailed craniofacial measurements have been obtained on each subject and composite pattern profiles compiled. The characteristic face of classical de Lange syndrome is present at birth and changes little throughout life, although there is some lengthening of the face with age and the jaw becomes squared. In mild de Lange syndrome, the characteristic classical appearance may be present at birth, but in some subjects it may be two or three years before the typical face is obvious. In general, the overall impression is less striking, perhaps because of increased facial expression and greater alertness. With age, the face loses the characteristic appearance, the nasal height increases, the philtrum does not seem as long, and the upper vermilion is full and everted, although the crescent shaped mouth with downturned corners remains. Eyebrows may be full and bushy. Objective comparison of the face in mild and classical de Lange syndrome, through the use of craniofacial pattern profiles, shows marked similarity of patterns at 4 to 9 years; both groups have microbrachycephaly, but the individual dimensions of the mild group are slightly closer to normal than their classical counterparts. The correlation coefficient is high (0.83). In the adult groups, similarity of patterns remains but is less marked. The normalisation of scores in the mild group is more dramatic. The correlation coefficient is lower (0.71). These objective findings substantiate clinical impressions of a phenotypic dichotomy. Early in life, the craniofacial features in mild de Lange syndrome may be indistinguishable from the classical phenotype and alternative discriminators must be sought in order to identify those subjects in whom the prognosis is more optimistic. Birth weight of more than 2500 g and absence of major limb anomalies may help in this regard.

A further report of Brachmann-de Lange syndrome in two sibs with normal parents

We report on a family in which a girl and a boy in the same sibship show variable manifestations of a less severe type of Brachmann-de Lange syndrome without significant prenatal growth deficiency and reduction deformities of the forearms. Both parents are healthy and phenotypically normal, and no other family members are affected. All the affected sibs except one described so far with normal parents presented the severe type of Brachmann-de Lange syndrome (now sometimes classified as type I: "classic" or "full" Brachmann-de Lange syndrome), with major upper limb anomalies, severe growth and mental retardation and, frequently, early death. We discuss the possible role of genomic imprinting in the etiology of this syndrome.

Partial trisomy 3q causing mild Cornelia de Lange phenotype

A brother and sister are reported with developmental delay and facial features suggestive of the Cornelia de Lange syndrome. Cytogenetic analysis showed them to be trisomic for the region 3q25.1-26.2 because of the inheritance of an unbalanced interchromosomal insertion from their father, who was a balanced insertion carrier. The clinical phenotype and cytogenetic analysis (including chromosome painting studies) in relation to the possible localisation of the Cornelia de Lange gene are discussed.

Clinical variability within Brachmann-de Lange syndrome: a proposed classification system

Seven patients, including two sibs, with the Brachmann-de Lange syndrome (BDLS) are presented as representative of the different types of BDLS in a proposed classification system. Type I ("classic") patients have the characteristic facial and skeletal changes of BDLS using the criteria in the diagnostic index of Preus and Rex. Type I is distinguished from the other subtypes by prenatal growth deficiency (< 2.5 S.D. below mean for gestation) becoming more severe postnatally (< 3.5 S.D. below the mean), moderate to profound psychomotor retardation, and major malformations which result in severe disability or death. Type II ("mild") BDLS patients have similar facial and minor skeletal abnormalities to those seen in type I; however, these changes may develop with time or may be partially expressed. Patients with type II BDLS are distinguished from those with other types by mild to borderline psychomotor retardation, less severe pre- and postnatal growth deficiency, and the absence of (or loss severe) major malformations. Behavioral problems can be a significant clinical problem in type II BDLS. Type III ("phenocopies") BDLS includes patients who have phenotypic manifestations of BDLS which are causally related to chromosomal aneuploidies or teratogenic exposures.

de Lange syndrome: a clinical review of 310 individuals

Three hundred ten individuals with a clinical diagnosis of de Lange syndrome were seen and examined in conjunction with the parent support group. One hundred thirty-four males and 176 females whose ages ranged from birth to 37 years made up the study group. Examination findings were recorded for those features described by de Lange in her original report of the syndrome to determine the frequency and significance of each. In addition, questionnaires were completed by 128 of these families and medical, growth and developmental records were collected. The clinical diagnosis seems best supported by the facial features of the syndrome including the long eyelashes and confluent eyebrows (synophrys), although additional characteristics are needed. Only 27% had the upper limb deficiencies commonly associated with the syndrome. Growth was retarded in nearly all individuals, often of prenatal onset. Medical problems occurred frequently and most often involved the eye and ear, as well as the cardiac and gastrointestinal systems. Of 14 deaths, almost half were secondary to cardiac or gastrointestinal complications. The recurrence risk in 377 sibs of the patients was calculated to be less than 1%. Although development lagged significantly in speech, most individuals developed good self-help skills. The study demonstrated a higher proportion of patients affected mildly with the syndrome than is commonly appreciated. This underscores the importance of early recognition and appropriate medical and developmental support.

Brachmann-de Lange syndrome: diagnostic difficulties posed by the mild phenotype

We describe 4 patients with facial changes of Brachmann-de Lange syndrome but without limb defects. Mental retardation ranged from moderate to severe and the degree of prenatal and postnatal growth deficiency was variable. These patients exemplify the diagnostic difficulties and counseling dilemmas posed by the mild Branchmann-de Lange phenotype. The relationship of the mild phenotype to the full syndrome will not be understood until the pathogenetic or causal factor(s) are delineated.

Familial Brachmann-de Lange syndrome: further evidence for autosomal dominant inheritance and review of the literature

We report on a mother and daughter with the Brachmann-de Lange syndrome which supports the view that in some families this disorder is due to autosomal dominant inheritance. A review of the literature concerning autosomal and recessive inheritance of this syndrome is presented.

A de novo translocation t(3;17)(q26.3;q23.1) in a child with Cornelia de Lange syndrome

A female infant with Cornelia de Lange syndrome and severe limb reduction defects is described. Chromosome analysis showed a de novo translocation with breakpoints at 3q26.3 and 17q23.1. This is the first reported case of a de novo translocation associated with this syndrome.