Rosalie Goldberg

Mutations in PTPN11 , encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome

Noonan syndrome (MIM 163950) is an autosomal dominant disorder characterized by dysmorphic facial features, proportionate short stature and heart disease (most commonly pulmonic stenosis and hypertrophic cardiomyopathy). Webbed neck, chest deformity, cryptorchidism, mental retardation and bleeding diatheses also are frequently associated with this disease. This syndrome is relatively common, with an estimated incidence of 1 in 1,000–2,500 live births. It has been mapped to a 5-cM region (N-SH2) on chromosome 12q24.1, and genetic heterogeneity has also been documented. Here we show that missense mutations in PTPN11 (MIM 176876)—a gene encoding the nonreceptor protein tyrosine phosphatase SHP-2, which contains two Src homology 2 (SH2) domains—cause Noonan syndrome and account for more than 50% of the cases that we examined. All PTPN11 missense mutations cluster in interacting portions of the amino N-SH2 domain and the phosphotyrosine phosphatase domains, which are involved in switching the protein between its inactive and active conformations. An energetics-based structural analysis of two N-SH2 mutants indicates that in these mutants there may be a significant shift of the equilibrium favoring the active conformation. This implies that they are gain-of-function changes and that the pathogenesis of Noonan syndrome arises from excessive SHP-2 activity.

Velo-cardio-facial syndrome associated with chromosome 22 deletions encompassing the DiGeorge locus

The large clinical overlap between DiGeorge syndrome and velo-cardio-facial syndrome suggests an aetiological connection. DiGeorge syndrome is associated with microdeletions of chromosome 22q11 and is therefore likely to be caused by reduced dosage of genes within this region. We present preliminary data that velocardiofacial syndrome patients have similar chromosome deletions, a finding consistent with the hypothesis that these disorders represent part of a spectrum of abnormalities seen with monosomy for 22q11.

Molecular Definition of 22q11 Deletions in 151 Velo-Cardio-Facial Syndrome Patients

Velo-cardio-facial syndrome (VCFS) is a relatively common developmental disorder characterized by craniofacial anomalies and conotruncal heart defects. Many VCFS patients have hemizygous deletions for a part of 22q11, suggesting that haploinsufficiency in this region is responsible for its etiology. Because most cases of VCFS are sporadic, portions of 22q11 may be prone to rearrangement. To understand the molecular basis for chromosomal deletions, we defined the extent of the deletion, by genotyping 151 VCFS patients and performing haplotype analysis on 105, using 15 consecutive polymorphic markers in 22q11. We found that 83% had a deletion and >90% of these had a similar approximately 3 Mb deletion, suggesting that sequences flanking the common breakpoints are susceptible to rearrangement. We found no correlation between the presence or size of the deletion and the phenotype. To further define the chromosomal breakpoints among the VCFS patients, we developed somatic hybrid cell lines from a set of VCFS patients. An 11-kb resolution physical map of a 1,080-kb region that includes deletion breakpoints was constructed, incorporating genes and expressed sequence tags (ESTs) isolated by the hybridization selection method. The ordered markers were used to examine the two separated copies of chromosome 22 in the somatic hybrid cell lines. In some cases, we were able to map the chromosome breakpoints within a single cosmid. A 480-kb critical region for VCFS has been delineated, including the genes for GSCL, CTP, CLTD, HIRA, and TMVCF, as well as a number of novel ordered ESTs.

Association of codon 108/158 catechol‐O‐methyltransferase gene polymorphism with the psychiatric manifestations of velo‐cardio‐facial syndrome

Velo-cardio-facial-syndrome (VCFS) is a common congenital disorder associated with typical facial appearance, cleft palate, cardiac defects, and learning disabilities. The majority of patients have an interstitial deletion on chromosome 22q11. In addition to physical abnormalities, a variety of psychiatric illnesses have been reported in patients with VCFS, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. The psychiatric manifestations of VCFS could be due to haploin-sufficiency of a gene(s) within 22q11. One candidate that has been mapped to this region is catechol-O-methyltransferase (COMT). We recently identified a polymorphism in the COMT gene that leads to a valine-->methionine substitution at amino acid 158 of the membrane-bound form of the enzyme. Homozygosity for COMT158met leads to a 3-4-fold reduction in enzymatic activity, compared with homozygotes for COMT158val. We now report that in a population of patients with VCFS, there is an apparent association between the low-activity allele, COMT158met, and the development of bipolar spectrum disorder, and in particular, a rapid-cycling form.

Genetic Heterogeneity of Saethre-Chotzen Syndrome, Due to TWIST and FGFR Mutations

Thirty-two unrelated patients with features of Saethre-Chotzen syndrome, a common autosomal dominant condition of craniosynostosis and limb anomalies, were screened for mutations in TWIST, FGFR2, and FGFR3. Nine novel and three recurrent TWIST mutations were found in 12 families. Seven families were found to have the FGFR3 P250R mutation, and one individual was found to have an FGFR2 VV269-270 deletion. To date, our detection rate for TWIST or FGFR mutations is 68% in our Saethre-Chotzen syndrome patients, including our five patients elsewhere reported with TWIST mutations. More than 35 different TWIST mutations are now known in the literature. The most common phenotypic features, present in more than a third of our patients with TWIST mutations, are coronal synostosis, brachycephaly, low frontal hairline, facial asymmetry, ptosis, hypertelorism, broad great toes, and clinodactyly. Significant intra- and interfamilial phenotypic variability is present for either TWIST mutations or FGFR mutations. The overlap in clinical features and the presence, in the same genes, of mutations for more than one craniosynostotic condition-such as Saethre-Chotzen, Crouzon, and Pfeiffer syndromes-support the hypothesis that TWIST and FGFRs are components of the same molecular pathway involved in the modulation of craniofacial and limb development in humans.

Cardiac malformations in the velocardiofacial syndrome

Abstract A similar pattern of congenital anomalies found in 27 children, 9 male and 18 female, aged 2 weeks to 17 years, allows the conclusion that they represent a newly recognized malformation syndrome. All patients had velopharyngeal insufficiency, a submucous or overt cleft of the secondary palate and learning disabilities. A similar facies, characterized by a long vertical face, a large fleshy nose with broad nasal bridge, flattened malar region, narrow palpebral fissures and deep overbite with retruded mandible, was usually present. Other noncardiac anomalies also occurred frequently. Twenty-three (85 percent) had congenital cardiovascular malformations whose occurrence as single or combined lesions far exceeded the expected incidence in children with congenital heart disease. A ventricular septal defect was present in 15, tetralogy of Fallot in 5. Prolapse of the right aortic cusp was present in two patients with a ventricular septal defect, and aortic valve disease with insufficiency in one patient with tetralogy. The aortic arch was right-sided in 12 patients, in conjunction with a ventricular septal defect in 5, in association with tetralogy of Fallot in 4 and in the absence of associated cardiac disease in 3. The right aortic arch descended on the right in 10 patients; in 2 with a ventricular septal defect it crossed retroesophageally to descend on the left, and in one of these it presented as the “third aortic arch syndrome.” Aberrant origin of the left subclavian artery was present in five patients with a right aortic arch. A patent ductus arteriosus had caused congestive heart failure in infancy in one patient with a small ventricular septal defect; three others with a ventricular defect had additional clinically minor anomalies. Two children were brother and sister. Their mother and the mothers of two other children showed evidence of the same syndrome, suggesting the possibility of autosomal dominant or X chromosome-linked dominant transmission.

Variable phenotypes in velocardiofacial syndrome with chromosomal deletion

Velocardiofacial syndrome (VCF) has overlapping features with DiGeorge sequence; both result from a developmental field defect and probably represent contiguous gene deletion syndromes. The association of chromosome 22q11 deletion with DiGeorge sequence led us to do molecular analysis of chromosome 22 in 18 patients with VCF, who ranged in age from 6 to 42 years. All 18 patients had monosomy for the chromosome region 22q11. Retrospectively, we correlated the presence of the deletion with various clinical findings: 100% had cleft palate, 67% the facial phenotype, 83% cardiac disease, 94% learning disabilities, 70% ophthalmologic findings, 50% short stature, 22% psychiatric disorders, and 17% hypocalcemia. Both severely phenotypically affected and mildly affected patients had the deletion. These findings stress the importance of continued surveillance of all patients with VCF for the many medical problems that may not be present at initial diagnosis. We conclude that the presence of the gene deletion does not predict the phenotypic expression in VCF. Further studies to characterize the size of the gene deletion may facilitate better prediction of the phenotype.

Ocular Findings in the Facioauriculovertebral Sequence (Goldenhar-Gorlin Syndrome)

We reviewed the ocular findings in 57 consecutive patients with the facioauriculovertebral sequence (Goldenhar-Gorlin syndrome). Epibulbar choristomas were detected in 18 cases (32%), a much lower occurrence than reported previously. Various motility disorders (11 cases, 19%), blepharoptosis or narrow palpebral fissures (seven cases, 12%), eyelid colobomas (six cases, 11%), and lacrimal drainage system anomalies (six cases, 11%) were more frequent than previously noted. These ocular findings were more common in the patients with epibulbar choristomas. Of the various features of the Goldenhar-Gorlin syndrome (skin tags, microtia, hemifacial microsomia, and vertebral anomalies), only skin tags correlated positively with the laterality of epibulbar choristomas. Preauricular and facial tags represent choristomas, explaining their association with epibulbar choristomas and the laterality they share.

Shprintzen-Goldberg syndrome: a clinical analysis.

Shprintzen-Goldberg syndrome is one of a group of disorders characterized by craniosynostosis and marfanoid habitus. Eleven cases were reported previously. We present 4 new patients and review one of the patients of the original report of Shprintzen and Goldberg [1982: J Craniofac Genet Dev Biol 2:65-74], 15 years later. The clinical and radiologic findings on our patients are compared with those of the previously reported patients and also with those of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224], who share many of the characteristics of Shprintzen-Goldberg syndrome. Some of the clinical data are helpful in determining if the patients of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224] have a separate syndrome or represent a variant of Shprintzen-Goldberg syndrome. However, radiologic investigations appear to be more specific, since an abnormality of the first and second cervical vertebrae, hydrocephalus, dilatation of the lateral ventricles, and a Chiari-I malformation of the brain were found only in the patients with Shprintzen-Goldberg syndrome. The apparently diagnostic findings of the 15 patients with this syndrome may be helpful in differentiating between Shprintzen-Goldberg syndrome and other syndromes with craniosynostosis and marfanoid habitus.

Ocular Findings in the Velo-cardio-facial Syndrome

Velo-cardio-facial syndrome is a common genetic syndrome of cleft palate, learning disability, heart disease, and abnormal facial appearance. Ocular findings include retinal vascular tortuosity, posterior embryotoxon, narrow palpebral fissures, suborbital discoloration, small optic nerves, iris nodules, and cataracts. Retinal vascular tortuosity was found to be associated intrinsically with the syndrome and not secondary to the heart disease. The ocular and systemic findings suggest a primary developmental anomaly of neural crest derivatives in the pathogenesis of the syndrome.