Sixteenth-century German woodcut of a male infant with possible disorganization.

History has preserved a beautiful 16th century woodcut print, which depicts an infant with several malformations. The German inscription describes the infant's hypotonia and ectopic growths, and the image itself shows a child with an ectopic accessory third lower limb, a large papilla, and an omphalocele-like growth. The 'case' bears striking similarity to reported human cases of the disorganization (Ds) syndrome. This article describes the woodcut, describes Ds, and then explains how the image may represent the earliest depiction of Ds in history.

A maternal hypomethylation syndrome presenting as transient neonatal diabetes mellitus.

The expression of imprinted genes is mediated by allele-specific epigenetic modification of genomic DNA and chromatin, including parent of origin-specific DNA methylation. Dysregulation of these genes causes a range of disorders affecting pre- and post-natal growth and neurological function. We investigated a cohort of 12 patients with transient neonatal diabetes whose disease was caused by loss of maternal methylation at the TNDM locus. We found that six of these patients showed a spectrum of methylation loss, mosaic with respect to the extent of the methylation loss, the tissues affected and the genetic loci involved. Five maternally methylated loci were affected, while one maternally methylated and two paternally methylated loci were spared. These patients had higher birth weight and were more phenotypically diverse than other TNDM patients with different aetiologies, presumably reflecting the influence of dysregulation of multiple imprinted genes. We propose the existence of a maternal hypomethylation syndrome, and therefore suggest that any patient with methylation loss at one maternally-methylated locus may also manifest methylation loss at other loci, potentially complicating or even confounding the clinical presentation.

Pediatric otolaryngologists' knowledge and understanding of genetic testing for deafness.

OBJECTIVE: To assess the level of a cohort of pediatric otolaryngologists' knowledge and understanding of genetics and genetic testing for deafness and hard of hearing (D/HOH). METHODS: A questionnaire was designed to assess the level of knowledge and understanding of the genetic basis and genetic testing for deafness among a cohort of pediatric otolaryngologists. Three hundred questionnaires were made available to attendees of the 14th (1999) Annual Meeting of the American Society of Pediatric Otolaryngology, Palm Desert, Calif. A series of questions asked to gauge the respondent's level of knowledge of genetics and hearing impairment addressed estimating recurrence risks for deaf and normal-hearing parents and the likelihood of detecting a mutation in connexin 26 in specific clinical scenarios. RESULTS: A total of 28 questionnaires were completed and returned. All respondents reported that they regularly saw patients for D/HOH. Almost half commonly refer these patients for genetic testing and counseling. Seventeen (71%) of 24 otolaryngologists stated they offered genetic testing in all situations, while 6 offered counseling only at parental request or to address recurrence risk issues. One otolaryngologist offered genetic testing if there was a deaf sibling. Twelve (67%) of 18 offered pretest counseling, which was most frequently provided by a genetic counselor. Although 3 (19%) of 16 otolaryngologists provided the counseling themselves, 2 (13%) reported that they and a genetic counselor provided the counseling. While 24 (89%) of the 27 correctly stated that nonsyndromic D/HOH is usually autosomal recessive, recurrence risks were incorrectly estimated in several examples. CONCLUSIONS: While the surveyed pediatric otolaryngologists have a good knowledge of genetics and genetic testing for D/HOH, recurrence risks were often inaccurate. Since D/HOH testing is clinically available, it is imperative that physicians are educated about genetics and genetic testing and are able to communicate this to their patients and their patients' families.

Distal 5q deletion syndrome: phenotypic correlations.

We describe the phenotypes of two male sibs with partial monosomy of chromosome 5 [46,XY,der(5)inv ins(1;5)(p32;q35.4q34)]; maternally derived from a balanced insertion of 1 and 5 [inv ins (1;5)(p.32;q35.4q34)]. One sib had microcephaly, cleft lip and palate, facial anomalies, atrial (ASD) and ventricular (VSD) septal defects, camptodactyly 4th and 5th fingers, and developmental delay. The other sib showed microcephaly, facial anomalies, ASD, hypotonia, primary optic nerve hypoplasia, and developmental delay. Only seven other patients with 5q deletions distal to 5q33 have been reported and none showed the putative breakpoints identified in our two patients. All nine showed developmental delay or malformations of the CNS and facial anomalies; six of nine had defects of cardiac septation. Our two patients and one other were shown to have only one copy of the cardiac specific hCSX gene that defines in part the etiology of their ASD and VSD. The other components of their phenotypes cannot be related at present to genes identified in the deleted segments.

Disorganization in mice and humans.

Disorganization (Ds) is an autosomal dominant mouse mutant that produces a remarkable array of birth defects. So variable is the phenotype that no two mice appear identical. Ds also has markedly reduced penetrance, with 85-99% of Ds mice having no apparent anomalies. Paired structures are often affected, but always asymmetrically. Although the Ds gene has yet to be identified, it is thought that Ds is a gain-of-function mutation, and that Ds malformations are thought to arise through a two-hit mechanism. Unlike the two-hit model that has been used to describe the development of retinoblastoma, the "second hit" for Ds is thought not to arise in the other Ds allele. Although there is a long list of anomalies seen in Ds mice, two stand out as most characteristic: hamartomatous skin papillae, and mirror-image limb duplications. Through the observation of these unusual anomalies in human cases, the possibility of a human homologue of Ds was suggested. However, in reviewing types of anomalies seen in Ds mice, it is apparent that cases with these unusual defects represent only one end of the spectrum of the Ds phenotype. Ds may be the genetic basis for more usual and seemingly sporadic human birth defects as well.

Genetic advances in central nervous system malformations in the fetus and neonate.

Malformations of the central nervous system (CNS) are commonly encountered by the pediatric neurologist when called to evaluate a fetus or newborn. Such malformations may be isolated or appear as part of a genetic syndrome. In the past few years there have been great advances in identifying the genes and genetic alterations for many isolated CNS malformations and syndromes with CNS malformations. Therefore, it is important to look for associated anomalies in any infant with a CNS malformation, as well as consideration of the rest of the family. We have chosen four malformations (holoprosencephaly, hydrocephalus, lissencephaly, and schizencephaly) to serve as a paradigm for genetic malformations of the CNS. Understanding the underlying genetic etiology of a disorder allows us to give more accurate recurrence risk counseling, to better estimate potential complications, and to better manage the patient's care. As research continues, additional malformations and syndromes will be understood on the genetic level, and combining this genetic information with neurologic understanding will translate into better medical care for the patient.

Genetic testing and genetic counseling for deafness: the future is here.

Today, genetic testing is an option for individuals who have deafness and hard-of-hearing conditions (D/HOH) and their families for diagnosis and carrier detection. As more and more D/HOH genes are identified, genetic testing will become commonplace. However, genetic testing is different from other tests that physicians commonly order and therefore should be conducted differently. The objective of this study was to determine the best manner in which to conduct genetic testing for individuals who have D/HOH. Numerous studies have shown that pretest and post-test genetic counseling is beneficial for patients and families undergoing genetic testing for a variety of conditions. The need for counseling was emphasized by our recently completed study in which we found that the majority of individuals whose children had genetic testing for D/HOH had a poor understanding of many genetic issues concerning recurrence risks for D/HOH and the meaning of the test results. We think that genetic counseling should be an integral part of genetic testing for individuals who have D/HOH.

What information do parents of newborns with cleft lip, palate, or both want to know?

BACKGROUND: The unexpected birth of a baby with a cleft lip and palate (CL/P) is a shocking and traumatic experience, generating anxiety for parents as well as the attendant health care team. Parents frequently leave the hospital with many unanswered questions because health care professionals do not educate them adequately. OBJECTIVE: To determine what information these parents felt was "critical" for them during the immediate newborn period and to determine how the "informer" was perceived during these encounters. DESIGN: Retrospective, self-administered questionnaire. SUBJECTS AND METHODS: Biologic parents of children with isolated CL/P aged 6 years and younger were surveyed. The questionnaire asked parents whether they remembered discussing diagnosis, prognosis, management, home care, and psychosocial issues. Parents were also asked to rank how "critical" it would have been for the "informer" to have discussed certain issues with them during this first day. RESULTS: Parents gave the highest priority to feeding and learning to identify illness in their baby; 95% wanted to be shown all normal aspects of their baby's exam, and 87% wanted to be told that the CL/P was not their fault. Usage of proper terminology to describe abnormal findings and receiving assurance that their child was not in pain were also important. Unfortunately, many parents reported that the informers did not address these issues. CONCLUSIONS: Parents of newborns with CL/P want basic information in the immediate newborn period, especially regarding feeding and recognizing illness. These data suggest that informers are not adequately discussing these issues with parents.

Parental attitudes toward genetic testing for pediatric deafness.

Recent molecular genetic advances have resulted in genetic testing becoming an option for deaf individuals and their families. However, there is little information about the interest in such testing. To investigate this issue, parents with normal hearing who have one or more deaf children were surveyed about their attitudes toward diagnostic, carrier, and prenatal genetic testing for deafness. This population was chosen because it represents the majority of individuals who are encountered in clinical practice, given that 90%-95% of deaf individuals are born to persons with normal hearing. Of 328 surveys distributed, 96 were completed and returned. Of the respondents, 96% recorded a positive attitude toward genetic testing for deafness, including prenatal testing, although none would use this information to terminate an affected pregnancy. All respondents had a poor understanding of genetics, with 98% both incorrectly estimating the recurrence risk of deafness and misunderstanding the concept of inheritance. Notably, these findings were similar in the group who had had genetic testing for their children and in the group who had not, suggesting either that the parents who received genetic testing did not receive genetic counseling or that the counseling was not effective. On the basis of these results, it was concluded that this population is interested in the use of genetic testing and that testing should not be done without first providing formal genetic counseling. Appropriate counseling can help parents to understand the risks, benefits, and limitations of genetic testing.

Adult with an interstitial deletion of chromosome 10 [del(10)(q25. 1q25.3)]: overlap with Coffin-Lowry syndrome.

We recently evaluated a mentally retarded 48 year old man found to have a cytogenetic deletion of chromosome 10 [46,XY,del(10) (q25. 1q25.3)]. Of interest, he shares many clinical findings with those described in Coffin-Lowry syndrome (CLS). These include severe mental retardation, short stature and a coarse facial appearance with widely spaced eyes, and patulous lips. He also had an extra transverse hypothenar crease, a finding that is seen in CLS. Furthermore, he has characteristic radiographic hand findings described in 95% of patients with CLS. The CLS gene, located at Xp22. 2, has recently been identified, and mutations in the Rsk-2 gene have been identified in several CLS patients. Rsk2 is part of a gene family implicated in cell cycle regulation through the mitogen-activated protein (MAP) kinase cascade. None of the currently recognized components of this pathway maps to the region deleted in our patient, nor are we able to identify any likely candidate genes in the deleted region, although several G protein coupled receptors have been cloned from the region. This patient's findings have some overlap with those seen in CLS, suggesting that a gene involved in MAP kinase signaling may be present in the deleted region of chromosome 10q25.1-25.3. Patients with a phenotype consistent with CLS, but lacking a family history suggestive of an X-linked disorder, should be evaluated with chromosome analysis paying particular attention to the region 10q25.

Epiglottic hypoplasia associated with lacrimo-auriculo-dental-digital syndrome.

We present a case of a young boy with clinical manifestations of lacrimo-auriculo-dental-digital syndrome (LADD) with the additional finding of a hypoplastic epiglottis that caused airway obstruction at birth. We also reviewed the 30 cases of LADD that have been reported since 1967. It is a rare syndrome that includes lacrimal system, aural, digital, and dental anomalies. Our patient has lacrimal duct obstruction, deficient tissue in the inferior portion of the ear pinnae, and a hypoplastic epiglottis with collapse of the supraglottic tissue. Many findings of LADD are recognizable at birth. The clinical spectrum has widened with more case reports. Our patient adds a life-threatening airway abnormality, a hypoplastic epiglottis, to the clinical spectrum of LADD.

Serum alpha-fetoprotein levels in Beckwith-Wiedemann syndrome.

We conducted a retrospective study that compared serial alpha-fetoprotein (AFP) concentrations obtained from 22 children with Beckwith-Wiedemann syndrome (BWS) with levels established for healthy children. The AFP concentration is greater in patients with BWS and declines during the postnatal period at a significantly slower rate than what is reported in healthy children. AFP levels obtained in the course of routine tumor screening in children with BWS should be interpreted with a normal curve established specifically for BWS rather than with previously published data for healthy infants and children.

Genetic counseling in primary care. What questions are patients likely to ask, and how should they be answered?

Clues to genetic disorders are often first discovered during routine healthcare visits. This can create a dilemma for both the physician and the patient about what to do next. Because human genetics is a rapidly advancing field, many physicians are wondering which elements of a patient's medical history warrant a visit to the genetics clinic and which should be simply watched. In this article, Ms Facher and Dr Robin answer specific questions that the primary care physician is likely to have or to be asked about the evolving science of genetic testing.

Agenesis of the corpus callosum associated with DiGeorge-velocardiofacial syndrome: a case report and review of the literature.

We report a patient with clinical and cytogenetic findings consistent with DiGeorge-velocardiofacial syndrome and agenesis of the corpus callosum. This patient represents the first report of a case of DiGeorge-velocardiofacial syndrome associated with such a central nervous system abnormality. This case, together with previous reports in the literature, suggests that structural brain abnormalities, and in particular abnormalities of the corpus callosum, are part of the complex syndrome associated with the chromosomal microdeletion 22q11.2. We suggest that the diagnosis of DiGeorge-velocardiofacial syndrome be entertained in patients with agenesis of the corpus callosum in the context of other common clinical features of this syndrome.

The mutational spectrum of the sonic hedgehog gene in holoprosencephaly: SHH mutations cause a significant proportion of autosomal dominant holoprosencephaly.

Holoprosencephaly (HPE) is a common developmental anomaly of the human forebrain and midface where the cerebral hemispheres fail to separate into distinct left and right halves. We have previously reported haploinsufficiency for Sonic Hedgehog ( SHH ) as a cause for HPE. We have now performed mutational analysis of the complete coding region and intron-exon junctions of the SHH gene in 344 unrelated affected individuals. Herein, we describe 13 additional unrelated affected individuals with SHH mutations, including nonsense and missense mutations, deletions and an insertion. These mutations occur throughout the extent of the gene. No specific genotype-phenotype association is evident based on the correlation of the type or position of the mutations. In conjunction with our previous studies, we have identified a total of 23 mutations in 344 unrelated cases of HPE. They account for 14 cases of familial HPE and nine cases of sporadic HPE. Mutations in SHH were detected in 10 of 27 (37%) families showing autosomal dominant transmission of the HPE spectrum, based on structural anomalies. Interestingly, three of the patients with an SHH mutation also had abnormalities in another gene that is expressed during forebrain development. We suggest that the interactions of multiple gene products and/or environmental elements may determine the final phenotypic outcome for a given individual and that variations among these factors may cause the wide variability in the clinical features seen in HPE.

Microcephaly-lymphedema-chorioretinal dysplasia: a unique genetic syndrome with variable expression and possible characteristic facial appearance.

We report on a follow-up examination of a family with microcephaly and lymphedema. The finding of chorioretinal dysplasia with variable visual deficit in multiple relatives, which was not previously discovered, supports the concept of microcephaly, lymphedema, and chorioretinopathy as being a single autosomal dominant genetic entity with variable expression. We recommend that fundoscopic examination be performed in all patients with microcephaly with or without lymphedema.

Clinical and molecular studies of brachydactyly type D.

We report on the clinical manifestations in six affected individuals from a four-generation family that segregates brachydactyly type D (BDD). All affected individuals have either bilateral and symmetric or unilateral first distal phalangeal hypoplasia. Metacarpal-phalangeal profiles show that some affected individuals also have a more generalized involvement of the apical skeleton. However, other than first distal phalangeal hypoplasia, there is no consistent pattern of associated skeletal involvement. Linkage analyses were preformed between the BDD phenotype in this family and six loci known to contain genes involved in apical skeletal patterning. No statistically significant linkage was detected.