Defects of B-cell terminal differentiation in patients with type-1 Kabuki syndrome

BACKGROUND

Kabuki syndrome (KS) is a complex multisystem developmental disorder associated with mutation of genes encoding histone-modifying proteins. In addition to craniofacial, intellectual, and cardiac defects, KS is also characterized by humoral immune deficiency and autoimmune disease, yet no detailed molecular characterization of the KS-associated immune phenotype has been reported.

OBJECTIVE

We sought to characterize the humoral immune defects found in patients with KS with lysine methyltransferase 2D (KMT2D) mutations.

METHODS

We comprehensively characterized B-cell function in a cohort (n = 13) of patients with KS (age, 4 months to 27 years).

RESULTS

Three quarters (77%) of the cohort had a detectable heterozygous KMT2D mutation (50% nonsense, 20% splice site, and 30% missense mutations), and 70% of the reported mutations are novel. Among the patients with KMT2D mutations (KMT2D(Mut/+)), hypogammaglobulinemia was detected in all but 1 patient, with IgA deficiency affecting 90% of patients and a deficiency in at least 1 other isoform seen in 40% of patients. Numbers of total memory (CD27(+)) and class-switched memory B cells (IgM(-)) were significantly reduced in patients with KMT2D(Mut/+) mutations compared with numbers in control subjects (P < .001). Patients with KMT2D(Mut/+) mutations also had significantly reduced rates of somatic hypermutation in IgG (P = .003) but not IgA or IgM heavy chain sequences. Impaired terminal differentiation was noted in primary B cells from patients with KMT2D(Mut/+) mutations. Autoimmune pathology was observed in patients with missense mutations affecting the SET domain and its adjacent domains.

CONCLUSIONS

In patients with KS, autosomal dominant KMT2D mutations are associated with dysregulation of terminal B-cell differentiation, leading to humoral immune deficiency and, in some cases, autoimmunity. All patients with KS should undergo serial clinical immune evaluations.

Identification of large NF1 duplications reciprocal to NAHR-mediated type-1 NF1 deletions

Approximately 5% of all patients with neurofibromatosis type-1 (NF1) exhibit large deletions of the NF1 gene region. To date, only nine unrelated cases of large NF1 duplications have been reported, with none of the affected patients exhibiting multiple café au lait spots (CALS), Lisch nodules, freckling, or neurofibromas, the hallmark signs of NF1. Here, we have characterized two novel NF1 duplications, one sporadic and one familial. Both index patients with NF1 duplications exhibited learning disabilities and atypical CALS. Additionally, patient R609021 had Lisch nodules, whereas patient R653070 exhibited two inguinal freckles. The mother and sister of patient R609021 also harbored the NF1 duplication and exhibited cognitive dysfunction but no CALS. The breakpoints of the nine NF1 duplications reported previously have not been identified and hence their underlying generative mechanisms have remained unclear. In this study, we performed high-resolution breakpoint analysis that indicated that the two duplications studied were mediated by nonallelic homologous recombination (NAHR) and that the duplication breakpoints were located within the NAHR hotspot paralogous recombination site 2 (PRS2), which also harbors the type-1 NF1 deletion breakpoints. Hence, our study indicates for the first time that NF1 duplications are reciprocal to type-1 NF1 deletions and originate from the same NAHR events.

Points to Consider: Ethical, Legal, and Psychosocial Implications of Genetic Testing in Children and Adolescents

In 1995, the American Society of Human Genetics (ASHG) and American College of Medical Genetics and Genomics (ACMG) jointly published a statement on genetic testing in children and adolescents. In the past 20 years, much has changed in the field of genetics, including the development of powerful new technologies, new data from genetic research on children and adolescents, and substantial clinical experience. This statement represents current opinion by the ASHG on the ethical, legal, and social issues concerning genetic testing in children. These recommendations are relevant to families, clinicians, and investigators. After a brief review of the 1995 statement and major changes in genetic technologies in recent years, this statement offers points to consider on a broad range of test technologies and their applications in clinical medicine and research. Recommendations are also made for record and communication issues in this domain and for professional education.

Case of Small Vessel Disease Associated with COL4A1 Mutations following Trauma

With this case report, we would like to heighten the awareness of clinicians about COL4A1 as a single-gene disorder causing cerebral small vessel disease and describe a previously unreported pathogenic missense substitution in COL4A1 (p.Gly990Val) and a new clinical presentation. We identified a heterozygous putatively pathogenic mutation of COL4A1 in a 50-year-old female with a history of congenital cataracts and glaucoma who presented with multiple diffusion-positive infarcts and areas of contrast enhancement following mild head trauma. We believe that this presentation of multiple areas of acute brain and vascular injury in the setting of mild head trauma is a new manifestation of this genetic disorder. Imaging findings of multiple acute infarcts and regions of contrast enhancement with associated asymptomatic old deep microhemorrhages and leukomalacia in adults after head trauma should raise a high suspicion for a COL4A1 genetic disorder. Radiographic patterns of significant leukoaraiosis and deep microhemorrhages can also be seen in patients with long-standing vasculopathy associated with hypertension, which our patient lacked. Our findings demonstrate the utility of genetic screening for COL4A1 mutations in young patients who have small vessel vasculopathy on brain imaging but who do not have significant cardiovascular risk factors.

A mutation in FRIZZLED2 impairs Wnt signaling and causes autosomal dominant omodysplasia

Autosomal dominant omodysplasia is a rare skeletal dysplasia characterized by short humeri, radial head dislocation, short first metacarpals, facial dysmorphism and genitourinary anomalies. We performed next-generation whole-exome sequencing and comparative analysis of a proband with omodysplasia, her unaffected parents and her affected daughter. We identified a de novo mutation in FRIZZLED2 (FZD2) in the proband and her daughter that was not found in unaffected family members. The FZD2 mutation (c.1644G>A) changes a tryptophan residue at amino acid 548 to a premature stop (p.Trp548*). This altered protein is still produced in vitro, but we show reduced ability of this mutant form of FZD2 to interact with its downstream target DISHEVELLED. Furthermore, expressing the mutant form of FZD2 in vitro is not able to facilitate the cellular response to canonical Wnt signaling like wild-type FZD2. We therefore conclude that the FRIZZLED2 mutation is a de novo, novel cause for autosomal dominant omodysplasia.

Predictive value of fetal lung volume in prenatally diagnosed skeletal dysplasia

OBJECTIVE

Pulmonary hypoplasia is a major cause of death in lethal skeletal dysplasias. We hypothesize that in fetuses with prenatally diagnosed skeletal dysplasia, comparison of observed-to-expected (O/E) lung volume will help predict lethality.

STUDY DESIGN

We conducted a retrospective chart review of patients referred for evaluation of suspected fetal skeletal anomalies. Twenty-three pregnancies were identified with confirmed fetal diagnosis of skeletal dysplasia for which fetal magnetic resonance imaging (MRI) was performed between 21 and 38 weeks of gestation and ultrasound biometry data were available. Femur length to abdominal circumference ratio (FL/AC) and O/E lung volumes were calculated. The association between O/E lung volume, FL/AC, and lethality was measured using logistic regression.

RESULTS

Lethality was significantly associated with O/E lung volume (p = 0.002) and FL/AC (p = 0.0476). Analysis with receiver-operating characteristic curves suggested that O/E lung volume of 47.9% or FL/AC of 0.124 could be useful clinical cutoffs in the prediction of lethality.

CONCLUSION

In fetuses with skeletal dysplasia, fetal MRI-derived O/E lung volume was predictive of lethality. When evaluating a fetal skeletal dysplasia, fetal MRI may be considered in cases for which ultrasound-based lethality prediction is ambiguous or uncertain in order to provide families with the most complete and accurate information.

Health supervision for children with Marfan syndrome

Marfan syndrome is a systemic, heritable connective tissue disorder that affects many different organ systems and is best managed by using a multidisciplinary approach. The guidance in this report is designed to assist the pediatrician in recognizing the features of Marfan syndrome as well as caring for the individual with this disorder.

Technical report: Ethical and policy issues in genetic testing and screening of children

The genetic testing and genetic screening of children are commonplace. Decisions about whether to offer genetic testing and screening should be driven by the best interest of the child. The growing literature on the psychosocial and clinical effects of such testing and screening can help inform best practices. This technical report provides ethical justification and empirical data in support of the proposed policy recommendations regarding such practices in a myriad of settings.

Neonates with Tongue-Based Airway Obstruction

Objective. In this systematic review, the authors summarize the current evidence in the literature regarding diagnosis, treatment, and long-term outcomes in neonates with tongue-based airway obstruction (TBAO) and assess the level of evidence of included studies.

Data Sources. The terms Pierre Robin syndrome/sequence, micrognathia, retrognathia, and cleft palate were combined with airway obstruction, treatment, tongue-lip plication, and osteogenesis distraction to perform an Ovid literature search, yielding 341 references. The authors excluded references containing patients with isolated choanal/nasal obstruction, patients older than 12 months, and expert opinion papers, yielding 126 articles.

Review Methods. The authors searched 3 electronic databases and reference lists of existing reviews from 1980 to October 2010 for articles pertaining to the diagnosis, treatment, and outcomes of TBAO. Reviewers assigned a level of evidence score based on Oxford’s Centre for Evidence Based Medicine scoring system and recorded relevant information.

Results. Most studies were case studies and single-center findings. The lack of standardization of diagnostic and treatment protocols and the heterogeneity of cohorts both within and between studies precluded a meta-analysis. There was little evidence beyond expert opinion and single-center evaluation regarding diagnosis, treatment, and long-term outcomes of neonates with TBAO.

Conclusions. The variability in the phenotype of the cohorts studied and the absence of standardized indications for intervention preclude deriving any definitive conclusions regarding diagnostic tools to evaluate this patient population, treatment choices, or long-term outcomes. A coordinated multicenter study with a standardized diagnostic and treatment algorithm is recommended to develop evidence for the diagnosis and treatment of neonates with TBAO.

Parental Perspectives of Children Born with Cleft Lip and/or Palate: A Qualitative Assessment of Suggestions for Healthcare Improvements and Interventions

Objective

To assess parental perspectives on effective interventions and to summarize parents’ suggestions for health care professionals to improve the care provided to their children born with cleft lip and/or palate.

Design

Qualitative interviews.

Setting

Comprehensive craniofacial center at a Midwest pediatric hospital.

Participants

Seventeen parents of children under the age of 1 who were born with CL/P.

Results

Interventions that parents identified as effective included repetition of information, showing pictures of other children (before and after surgery), and anticipatory guidance about surgeries and their child's development. Despite the high level of satisfaction, parents expressed a desire for health care professionals to use more written and visual information, to have more contact with other parents of children born with clefts, and for health care professionals outside the Craniofacial Center to be more knowledgeable about CL/P.

Conclusions

Although parents of children with CL/P were for the most part satisfied with their children's care, the parents who were interviewed for this study suggested attainable changes that may result in more constructive and positive involvement of parents as integral members of the craniofacial team.

Evaluation of growth in patients with isolated cleft lip and/or cleft palate

OBJECTIVE

The purpose of the study was to evaluate the growth of patients with isolated cleft lip (CL), with or without cleft palate (CP), or CP during the first few years of life.

METHODS

A retrospective analysis of data from birth to 5 years for 307 patients with isolated CL/CP or CP alone who were seen in a large craniofacial center between 1980 and 2007 was performed. We analyzed growth patterns and feeding interventions. Anthropometric values were plotted onto 2000 Centers for Disease Control and Prevention charts. Longitudinal analyses were performed to estimate age-related changes and to test whether feeding interventions or early education influenced age-related changes.

RESULTS

Including progressive weight, length, and head circumference values, a total of 1944 data points were available. The most frequent diagnosis was unilateral CL with CP (165 [53.7%] of 307 cases). No patients experienced significant failure to thrive during the study period, although predicted weight and length percentiles for age had initial decreases during the first year of life, with nadirs at 5.2 and 15 months, respectively. These decreases were followed by recovery that started at approximately 12 months for weight and at 20 months for length (P < .0001). Patients who had feeding interventions had a significantly (P = .047) increased gain rate over time for weight for length, compared with those who did not.

CONCLUSIONS

In this population, there were weight and length decreases during the first year of life, which were not clinically significant and were followed by statistically significant recovery. Recovery seemed to be related to successful education and feeding interventions. Head circumference and weight for length started at lower percentiles but showed consistent gain over time.

Intestinal malrotation in a patient with Pfeiffer syndrome type 2

Pfeiffer syndrome is a pleiotropic disorder characterized by multiple suture craniosynostosis, broad and medially deviated thumbs and great toes, and variable cutaneous syndactyly. We present the case of a 16-month-old boy with Pfeiffer syndrome type 2 who presented with intestinal malrotation for which the diagnosis was delayed. This is a rare complication of Pfeiffer syndrome, with few reported cases in the literature. This case illustrates the importance of recognizing gastrointestinal malrotation as a possible cause of feeding intolerance and persistent vomiting in patients with the severe forms of Pfeiffer syndrome.

DiGeorge anomaly in the absence of chromosome 22q11.2 deletion

OBJECTIVE

To test the hypothesis that the prevalence of deletion 22q11.2 among individuals who meet criteria for DiGeorge anomaly (DGA) is lower than the 90% commonly cited.

STUDY DESIGN

Participants were identified through retrospective chart reviews on all patients who underwent testing for deletion 22q11.2 and all patients with a diagnosis of "DiGeorge" or any of the major criteria associated with DGA at a large pediatric hospital over a period of 6 years. DGA was confirmed in 64 individuals, based on the presence of at least 2 of the following features: (1) cellular immune deficiency and/or absence of part or all of the thymus; (2) hypocalcemia and/or parathyroid deficiency; (3) congenital heart disease.

RESULTS

Of the 64 individuals with DGA, 29 (45%) did not have a chromosome 22q11.2 deletion. Among this deletion-negative subset, diabetic embryopathy and other chromosome abnormalities were the most commonly recognized underlying etiologies.

CONCLUSIONS

These findings challenge a widely held belief that nearly 90% of DGA is due to chromosome 22q11.2 deletion. This study also calls attention to the heterogeneity of DGA, highlights similarities and differences between those with and without a chromosome 22q11.2 deletion, and attempts to resolve some confusing features of conditions associated with DGA.

Characterization of congenital anomalies in individuals with choanal atresia

OBJECTIVE

To review a tertiary care pediatric hospital's experience with choanal atresia and stenosis (CA/S) related to associated congenital anomalies (birth defects, including minor abnormalities) and genetic disorders.

DESIGN

Retrospective case series.

SETTING

Tertiary care pediatric hospital.

PATIENTS

Individuals with CA/S.

MAIN OUTCOME MEASURES

Identification of congenital anomalies, neurologic abnormalities, and developmental disabilities in individuals with CA/S.

RESULTS

One hundred twenty-nine individuals with CA/S were evaluated between July 1, 1997, and July 1, 2007. Choanal atresia and stenosis was an isolated finding in 34 patients (26.4%) and was associated with other anomalies in 95 patients (73.6%). Specific conditions were diagnosed in 66 patients (51.2%); CHARGE (coloboma, heart defect, atresia choanae, retarded growth, genitourinary abnormalities, and ear anomalies) syndrome was the most common diagnosis (33 patients [25.6%]). Numerous conditions were seen, including chromosomal abnormalities, single-gene defects, deformations, and those caused by teratogens. Choanal atresia and stenosis was unilateral in 62 patients (48.1%) and was bilateral in 60 patients (46.5%). Unilateral cases were more likely to be isolated (30 patients [53.2%]). Bilateral cases were more likely to be associated with specific disorders or multiple congenital anomalies (60 patients [98.4%]). There was no difference in laterality among unilateral cases.

CONCLUSIONS

Choanal atresia and stenosis is associated with a wide range of disorders. Congenital anomalies, neurologic abnormalities, and developmental disabilities are commonly identified in affected individuals. Bilateral CA/S is more commonly seen in patients in whom specific diagnoses or other congenital anomalies are identified. Unilateral CA/S occurs more frequently in isolated cases. A comprehensive evaluation is recommended in individuals with CA/S to evaluate for other congenital anomalies, neurologic abnormalities, developmental delays, and evidence of a specific underlying disorder.

Interstitial deletion of 13q associated with polymicrogyria

Interstitial deletion of the long arm of chromosome 13 is a rare condition characterized by multiple clinical findings. We report a male dizygotic twin with an interstitial deletion of 13q and failure to thrive, hypotonia, polymicrogyria, bilateral foci of retinoblastoma, hearing loss, bilateral inguinal hernias, submucous cleft palate, and dysmorphic features including a triangular shaped face, broad forehead, small chin, prominent eyes, downslanting palpebral fissures, and a downturned mouth. Chromosome analysis showed an interstitial deletion of chromosome 13 which was confirmed by fluorescence in situ hybridization analysis to include the Rb locus, but spare the 13q subtelomeric region. The karyotype was 46,XY,del(13)(q14.1q31.2).ish del(13)(RB1-,D13S327+) de novo. Breakpoints were further characterized by SNP-based microarray. Retinoblastoma tumors are a well-known complication of deletion of the retinoblastoma susceptibility gene, located at chromosome 13q14.2. Growth retardation is another common feature that has been described in other patients with a deletion of 13q. Additionally, this patient had brain findings on MRI consistent with bilateral polymicrogyria with predominance of the frontal lobes, as well as prominent infratentorial and supratentorial vasculature. There are a variety of polymicrogyria syndromes that are distinguished by the cortical location of the abnormal folding. Several of the subtypes have known genetic loci associated with them. To our knowledge, this is the only report of polymicrogyria in association with a deletion of chromosome 13.

Age at first birth and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

An early age at first full-term birth is associated with a reduction in the subsequent development of breast cancer among women in the general population. A similar effect has not yet been reported among women who carry an inherited BRCA1 or BRCA2 mutation. We conducted a matched case-control study on 1816 pairs of women with a BRCA1 (n = 1405) or BRCA2 (n = 411) mutation in an attempt to elucidate the relationship between age at first full-term pregnancy and the risk of developing breast cancer. Information about the age at first childbirth and other pregnancy-related variables was derived from a questionnaire administered to women during the course of genetic counselling. There was no difference in the mean age at first full-term birth in the cases and controls (24.9 years vs. 24.8 years; P = 0.81, respectively). Compared to women whose first child was born at or before 18 years of age, a later age at first full-term birth did not influence the risk of developing breast cancer (OR = 1.00 per year; 95% CI 0.98-1.03; P-trend = 0.67). Stratification by mutation status did not affect the results. These findings suggest that an early first full-term birth does not confer protection against breast cancer in BRCA mutation carriers. Nonetheless, BRCA mutation carriers opting for a prophylactic oophorectomy as a breast and/or ovarian cancer risk-reducing strategy should complete childbearing prior to age 40 when this prevention modality is most effective.

Epidemiology of hemimegalencephaly: a case series and review

Hemimegalencephaly (HME) is a congenital brain malformation characterized by unilateral enlargement of the cerebral hemisphere. Clinically, HME is typically associated with hemiparesis, psychomotor retardation, and intractable seizures usually apparent soon after birth. HME is often an isolated finding, but it has been described as an occasional feature of a large number of syndromes, many of which may not be readily identified at birth. There are a multitude of case series and reports of HME in the English literature; however, there is no comprehensive, unbiased, detailed survey characterizing the proportion of cases of HME that are associated with a syndrome. We performed a retrospective study of all cases of HME seen at our institution from 1990 to 2003. Of the 15 cases of HME identified, 53% (8/15) were non-syndromic and 47% (7/15) of the cases were associated with a known or suspected genetic syndrome. In patients with syndromic HME, many of the syndromic features were not readily discernible at birth or in early infancy. It is, therefore, imperative to continually evaluate any infant with HME for signs and symptoms of these and other syndromes. Knowing the relative differential diagnosis will lead to a more comprehensive evaluation, improvement in expectant management, and appropriate counseling of families before considering radical surgical options such as hemispherectomy.

Spontaneous and therapeutic abortions and the risk of breast cancer among BRCA mutation carriers

Introduction

BRCA1 and BRCA2 mutation carriers are at increased risk for developing both breast and ovarian cancer. It has been suggested that carriers of BRCA1/2 mutations may also be at increased risk of having recurrent (three or more) miscarriages. Several reproductive factors have been shown to influence the risk of breast cancer in mutation carriers, but the effects of spontaneous and therapeutic abortions on the risk of hereditary breast cancer risk have not been well studied to date.

Methods

In a matched case-control study, the frequencies of spontaneous abortions were compared among 1,878 BRCA1 mutation carriers, 950 BRCA2 mutation carriers and 657 related non-carrier controls. The rates of spontaneous and therapeutic abortions were compared for carriers with and without breast cancer.

Results

There was no difference in the rate of spontaneous abortions between carriers of BRCA1 or BRCA2 mutations and non-carriers. The number of spontaneous abortions was not associated with breast cancer risk among BRCA1 or BRCA2 mutation carriers. However, BRCA2 carriers who had two or more therapeutic abortions faced a 64% decrease in the risk of breast cancer (odds ratio = 0.36; 95% confidence interval 0.16–0.83; p = 0.02).

Conclusion

Carrying a BRCA1 or BRCA2 mutation is not a risk factor for spontaneous abortions and spontaneous abortions do not appear to influence the risk of breast cancer in carriers of BRCA1 or BRCA2 mutations. However, having two or more therapeutic abortions may be associated with a lowered risk of breast cancer among BRCA2 carriers.

Age at menarche and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

Age at menarche is a strong and consistent predictor of breast cancer risk in the general population, but has not been well studied in women with a family history of breast cancer. We conducted this study to examine whether the presence of a deleterious BRCA1 or BRCA2 mutation influences age at menarche and to investigate whether or not there is an association between age at menarche and the risk of breast cancer in BRCA1 or BRCA2 mutation carriers. The presence of a deleterious BRCA1 or BRCA2 mutation did not appear to influence a woman's age at menarche. A matched case-control study was conducted on 1311 pairs of women who have been identified to be carriers of a deleterious mutation in either the BRCA1 (n = 945 pairs) or the BRCA2 gene (n = 366 pairs). Information about age at menarche was derived from a questionnaire routinely administered to carriers of a mutation in either gene. Among women who carried a deleterious BRCA1 mutation, age at menarche was inversely associated with the risk of breast cancer (p trend = 0.0002). This association was not observed among BRCA2 mutation carriers (p trend = 0.49). Compared with BRCA1 carriers whose age at menarche was < or =11 years, women with a menarcheal age between 14 and 15 years old had a 54% reduction in risk (OR = 0.46; 95% CI 0.30-0.69). This study implicates early age at menarche as a determinant of breast cancer among women with a BRCA1 mutation.

Valproate embryopathy: clinical and cognitive profile in 5 siblings

Valproate embryopathy is a well recognized syndrome caused by prenatal exposure to the anticonvulsant valproic acid (Depakote). We report five half-siblings with the same mother (four different fathers) who all have valproate embryopathy. Valproic acid was the sole anticonvulsant in all five pregnancies, with doses ranging from 500 to 2,000 mg per day. All children were examined by a clinical geneticist and developmental pediatrician, and had formal developmental testing. Mean birth weight at term was 2,900 g (range: 2,400-3,400 g). Common features in the five children included: flat, broad nasal bridge (5/5), hypoplastic midface (4/5), apparent hypertelorism/telecanthus (4/5), smooth philtrum (4/5), thin upper lip (5/5), long thin tapering fingers (4/5), hypoplastic 5th toenails (2/5), and irregularly placed toes (2/5). Less frequent features were micro/brachycephaly (2/5), cleft palate (1/5), duplication cyst of small intestine (1/5), and hemangioma (1/5). None had neural tube defect. Neuropsychologic testing of the three children older than 4 years of age showed cognitive ability in the low normal or borderline range (mean IQ = 83; range: 75-86), with significantly lower scores in adaptive behavior and motor skills. Study of this family offers insight into the potentially high risk of valproate embryopathy in exposed pregnancies, and affords a unique opportunity to study the variability of expression and cognitive profile of the syndrome within one family.

Family communication about positive BRCA1 and BRCA2 genetic test results

PURPOSE

The identification of a BRCA1 or BRCA2 genetic mutation can provide important health information to individuals who receive this result, but it can also provide crucial cancer risk information to family members. Most of the research on communication of genetic test results has focused on first degree relatives. The purpose of this retrospective study was to examine the process of communicating a positive BRCA1 or BRCA2 genetic test result to male and female first, second, and third degree relatives.

METHODS

Participants were 38 female mutation carriers who responded to a written survey assessing the number and relationship of relatives informed, methods used to inform relatives, topics discussed, and motivations and barriers for communication.

RESULTS

Overall, 59% (470/803) of first, second, and third degree relatives were informed. The proportion of informed parents, siblings, and offspring was nearly twice that of more distant relatives including nieces, nephews, aunts, uncles, grandchildren, and cousins (88% versus 45%; P = 0.02). The method of communication differed by the gender of the relative, as did some of the topics discussed. The most important reasons for discussing the genetic test results were (1) to inform the relatives of their risk, (2) to suggest that they be tested, and (3) to fulfill a perceived duty to inform. The major barrier to communication was little contact and/or emotionally distant relationships.

CONCLUSION

Female mutation carriers act on a perceived duty to inform close relatives of their positive test result; however, there is a need for genetic counseling strategies that address communication with more distant relatives.

Dilated ascending aorta in a child with ring chromosome 21 syndrome

Ring chromosome 21 syndrome is a rare condition with a well-characterized phenotype. Affected individuals have recognizable dysmorphic features, developmental delays, growth retardation, and a predisposition for congenital malformations involving the neurologic, craniofacial, digestive, genitourinary, skeletal, and hematologic systems. Structural cardiac anomalies have also been described, but dilated ascending aorta has not been previously reported in association with ring 21 (r(21)). Although rarely seen in this syndrome, the presence of ectopia lentis, abdominal herniae, and dilated ascending aorta suggest an underlying connective tissue disorder. A possible explanation is haploinsufficiency of the COL6A1, COL6A2, and/or COL18A genes located on the distal portion of chromosome 21q, which are lost when the ring chromosome is formed. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148-7299/suppmat/index.html.

Upper airway malformation associated with partial trisomy 11q

11q trisomy is associated with a recognizable pattern of multiple malformations. Review of the literature reveals the following recurrent themes common to complex and isolated 11q trisomy: mental retardation, pre- and postnatal growth retardation, hypotonia, a distinct pattern of facial features, congenital heart defects, and limb malformations. We report four patients with partial trisomy 11q, none of which arose from the common 11/22 translocation. Three of the four patients had the previously unreported finding of upper airway obstruction secondary to a malformed epiglottis. The critical region for this malformation appears to be 11q21-23.2.

Unexpected survival in a case of prenatally diagnosed non-mosaic trisomy 22: Clinical report and review of the natural history

Over 30 cases of complete non-mosaic trisomy 22 have been reported in the literature in the last 20 years [Crowe et al., 1997: Am J Med Genet 71:406-413]. Twenty-two infants were liveborn with an average life expectancy of four days. Of these, nine survived beyond the first two weeks of life. The life span ranged from minutes to 3 years of age. We report a case of an infant diagnosed prenatally with complete non-mosaic trisomy 22. Options such as aggressive medical/surgical intervention or limiting interventions to symptomatic care including home hospice were discussed openly. Given this information, the family elected to provide minimal supportive measures with pediatric hospice. The infant lived for 2 months with her family before her death. Numerous medical and surgical complications are associated with this disorder. Both the family and the medical team must be prepared for in utero fetal demise, stillbirth, or for limited life expectancy. Proper management, therefore, depends upon an understanding of the diagnosis.