Hypophosphatasia: nonlethal disease despite skeletal presentation in utero (17 new cases and literature review)

Hypophosphatasia (HPP) is caused by deactivating mutation(s) within the gene that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). Patients manifest rickets or osteomalacia and dental disease ranging from absence of skeletal mineralization in utero to only loss of adult dentition. Until recently, HPP skeletal disease in utero was thought to always predict a lethal outcome. However, several reports beginning in 1999 emphasized a benign prenatal form of HPP (BP-HPP) where skeletal disease detected in utero had a mild postnatal course. Here we describe prenatal and postnatal findings of 17 additional BP-HPP patients among our 178 pediatric HPP patients. Their findings are compared with those of their siblings with HPP, carrier parents, and others with identical TNSALP mutations. New information concerning 7 previously published BP-HPP patients accompanies a review of the HPP literature. Among our 17 BP-HPP patients, prenatal ultrasound showed normal chest or abdominal circumferences where recorded. Sometimes, poor skeletal mineralization, fetal crowding, and third-trimester improvement were observed. Postnatally, extremity bowing further improved (13 patients). BP-HPP severity postnatally spanned the "infantile" to "odonto" HPP phenotypes, resembling our patients who harbored identical TNSALP mutation(s). Eight had autosomal dominant (AD) and 9 had autosomal recessive (AR) BP-HPP. Fourteen of our 15 mothers were HPP carriers or affected. Of the 41 cumulative BP-HPP patients (24 literature cases meriting a BP-HPP diagnosis since 1996 plus our 17 patients), 63% had AR BP-HPP. Maternally transmitted HPP involved 11 of the 13 total AD BP-HPP probands (p = 0.01), supporting a maternal in utero effect on the baby. Fetal crowding, normal fetal mineralization and chest size, and TNSALP heterozygosity seem to identify BP-HPP. However, bowed fetal long bones with AR HPP, specific TNSALP mutations, or poor skeletal mineralization before the third trimester do not reliably diagnose HPP lethality.

20p11 deletion in a female child with panhypopituitarism, cleft lip and palate, dysmorphic facial features, global developmental delay and seizure disorder

Deletions of 20p are rare with the majority of reported cases involving individuals with 20p12 deletions associated with Alagille syndrome. We report on a child with a de novo mosaic 20p11 deletion who presents with panhypopituitarism; hypoplastic pituitary gland and ectopic posterior pituitary gland on MRI of the brain; cleft lip and palate; kyphosis with anterior beaking of L1 and L2 vertebral bodies; pulmonic stenosis; dysmorphic facial features including flat nasal bridge, hypoplastic premaxilla, hypotelorism, preauricular pit, and cupped ears; seizure disorder; variable muscle tone; and global developmental delay. Array comparative genomic hybridization revealed this deletion to be approximately 5.4 Mb in size, containing 35 genes. Previously, an infant with 20p11.22 deletion who had panhypopituitarism, craniofacial, and genital abnormalities was reported, but the precise parameters of that deletion are unavailable. Several other reported cases of 20p11 deletions also have phenotypic overlap with our case. The similarities in clinical features of these patients suggest that the genes at 20p11 have a critical role in development of midline brain structures.

Health supervision for children with fragile X syndrome

Fragile X syndrome (an FMR1-related disorder) is the most commonly inherited form of mental retardation. Early physical recognition is difficult, so boys with developmental delay should be strongly considered for molecular testing. The characteristic adult phenotype usually does not develop until the second decade of life. Girls can also be affected with developmental delay. Because multiple family members can be affected with mental retardation and other conditions (premature ovarian failure and tremor/ataxia), family history information is of critical importance for the diagnosis and management of affected patients and their families. This report summarizes issues for fragile X syndrome regarding clinical diagnosis, laboratory diagnosis, genetic counseling, related health problems, behavior management, and age-related health supervision guidelines. The diagnosis of fragile X syndrome not only involves the affected children but also potentially has significant health consequences for multiple generations in each family.

Molecular analysis expands the spectrum of phenotypes associated with GLI3 mutations

A range of phenotypes including Greig cephalopolysyndactyly and Pallister-Hall syndromes (GCPS, PHS) are caused by pathogenic mutation of the GLI3 gene. To characterize the clinical variability of GLI3 mutations, we present a subset of a cohort of 174 probands referred for GLI3 analysis. Eighty-one probands with typical GCPS or PHS were previously reported, and we report the remaining 93 probands here. This includes 19 probands (12 mutations) who fulfilled clinical criteria for GCPS or PHS, 48 probands (16 mutations) with features of GCPS or PHS but who did not meet the clinical criteria (sub-GCPS and sub-PHS), 21 probands (6 mutations) with features of PHS or GCPS and oral-facial-digital syndrome, and 5 probands (1 mutation) with nonsyndromic polydactyly. These data support previously identified genotype-phenotype correlations and demonstrate a more variable degree of severity than previously recognized. The finding of GLI3 mutations in patients with features of oral-facial-digital syndrome supports the observation that GLI3 interacts with cilia. We conclude that the phenotypic spectrum of GLI3 mutations is broader than that encompassed by the clinical diagnostic criteria, but the genotype-phenotype correlation persists. Individuals with features of either GCPS or PHS should be screened for mutations in GLI3 even if they do not fulfill clinical criteria.

Identification of a previously unrecognized microdeletion syndrome of 16q11.2q12.2

We report the identification of microdeletions of 16q11.2q12.2 by microarray-based comparative genomic hybridization (aCGH) in two individuals. The clinical features of these two individuals include hypotonia, gastroesophageal reflux, ear anomalies, and toe deformities. Other features include developmental delay, mental retardation, hypothyroidism, and seizures. The identification of common clinical features in these two individuals and those of one other report suggests microdeletion of 16q12.1q12.2 is a rare, emerging syndrome. These results illustrate that aCGH is particularly suited to identify rare chromosome abnormalities in patients with apparently non-syndromic idiopathic mental retardation and birth defects.

Aggressive Osteoblastoma: A Case Report Involving a Unique Chromosomal Aberration

Osteoblastomas are rare bone-producing neoplasms that generally occur in the young and can be misdiagnosed as an osteosarcoma if correlation with clinical history, radiology, and histology is not carefully considered or if the several variants of osteoblastoma are not recognized. These variants lie on a morphologic spectrum between conventional osteoblastoma and osteosarcoma. Aggressive osteoblastoma is one such subtype. As the name implies, the histologic features of aggressive osteoblastoma may appear malignant, and its biologic behavior may separate it from conventional osteoblastoma. We report a case of aggressive osteoblastoma occurring in the femoral diaphysis of a 12-year-old girl; this osetoblastoma was dyssynchronous from the radiologic appearance and a diagnostic challenge. Cytogenetic evaluation of the neoplasm revealed a pseudodiploid clone with a balanced translocation involving chromosomes 4, 7, and 14. Using the premise that cytogenetics might be useful as a diagnostic tool for a more specific classification, we reviewed the literature in order to compare our findings with known chromosomal aberrations.

Expanding the clinical phenotype of the 3q29 microdeletion syndrome and characterization of the reciprocal microduplication

Background

Interstitial deletions of 3q29 have been recently described as a microdeletion syndrome mediated by nonallelic homologous recombination between low-copy repeats resulting in an ~1.6 Mb common-sized deletion. Given the molecular mechanism causing the deletion, the reciprocal duplication is anticipated to occur with equal frequency, although only one family with this duplication has been reported.

Results

In this study we describe 14 individuals with microdeletions of 3q29, including one family with a mildly affected mother and two affected children, identified among 14,698 individuals with idiopathic mental retardation who were analyzed by array CGH. Eleven individuals had typical 1.6-Mb deletions. Three individuals had deletions that flank, span, or partially overlap the commonly deleted region. Although the clinical presentations of individuals with typical-sized deletions varied, several features were present in multiple individuals, including mental retardation and microcephaly. We also identified 19 individuals with duplications of 3q29, five of which appear to be the reciprocal duplication product of the 3q29 microdeletion and 14 of which flank, span, or partially overlap the common deletion region. The clinical features of individuals with microduplications of 3q29 also varied with few common features. De novo and inherited abnormalities were found in both the microdeletion and microduplication cohorts illustrating the need for parental samples to fully characterize these abnormalities.

Conclusion

Our report demonstrates that array CGH is especially suited to identify chromosome abnormalities with unclear or variable presentations.

Health supervision for children with neurofibromatosis

Neurofibromatosis 1 is a multisystem disorder that primarily involves the skin and nervous system. Its population prevalence is 1 in 3500. The condition usually is recognized in early childhood, when cutaneous manifestations are apparent. Although neurofibromatosis 1 is associated with marked clinical variability, most affected children do well from the standpoint of their growth and development. Some features of neurofibromatosis 1 are present at birth, and others are age-related abnormalities of tissue proliferation, which necessitate periodic monitoring to address ongoing health and developmental needs and to minimize the risk of serious medical complications. This clinical report provides a review of the clinical criteria needed to establish a diagnosis, the inheritance pattern of neurofibromatosis 1, its major clinical and developmental manifestations, and guidelines for monitoring and providing intervention to maximize the growth, development, and health of an affected child.

Intellectual abilities and adaptive behavior of children and adolescents with Kabuki syndrome: A preliminary study

Very little is known about the intellectual abilities and adaptive behavior of individuals who have Kabuki syndrome, beyond the fact that most individuals with this syndrome have mental retardation. To fill this gap, we have completed psychological assessments of 11 children and adolescents with Kabuki syndrome. Results indicated that most of the participants functioned in the range of mild mental retardation, with both intellectual and adaptive behavior in the mildly deficient range and problem behaviors, if any, limited to mild difficulties with inattention and/or hyperactivity-impulsivity and mild problems with obsession/anxiety. At the lower extreme, one child evidenced severe mental retardation and profound adaptive behavior impairment accompanied by serious externalizing and internalizing problem behaviors. At the upper extreme, one adolescent had average intelligence and adaptive behavior, with problem behaviors well within the normal range for his chronological age. Most participants evidenced relative intellectual strengths in verbal and reasoning abilities and a relative weakness in visuospatial construction abilities. This pattern affected adaptive behavior as well, yielding a relative strength in Social Interaction and Communicative Skills and considerable weakness in Motor Skills and Personal Living Skills.

Patient with terminal duplication 3q and terminal deletion 5q: comparison with the 3q duplication syndrome and distal 5q deletion syndrome

Partial duplication of chromosome 3q is a well-described condition of multiple congenital anomalies and developmental delay that resembles the Brachmann-de Lange syndrome. Similarly, an emerging phenotype of a distal 5q deletion syndrome has recently been described. The combination of both chromosome abnormalities has not been previously described. We report on a child with both a de novo duplication of distal 3q (q27 --> qter) and terminal deletion of 5q (q35.2 --> qter). The patient had facial anomalies, hypoplastic toenails, lymphedema of the dorsum of the feet, type I Chiari malformation, a seizure disorder, and moderate developmental delays. The phenotype is compared and contrasted to the few reports of patients with similar terminal 3q duplications and 5q deletions. Our patient did not have the characteristic phenotype of the 3q duplication syndrome, suggesting that the chromosome region responsible for this phenotype is more proximal than the terminal 3q27 region. In addition, comparison with three other reported cases of terminal 5q35 deletions suggests a possible association of terminal 5q deletions with central nervous system (CNS) structural abnormalities.

Partial duplication 4q and deletion 1p36 in monozygotic twins with discordant phenotypes

We report on monozygotic (MZ) twins with a de novo chromosome abnormality consisting of a partial duplication of chromosome 4 (q25-qter) and deletion of chromosome 1p36. These infants had dysmorphic facial features and other clinical manifestations similar to those described with the previously delineated duplication 4q and deletion 1p36 phenotypes and two other reported cases of combined partial duplication 4q and deletion 1p36. However, the twins were discordant for a number of congenital anomalies. The discordant phenotypes described in these genetically identical infants demonstrate that nongenetic factors may play a significant role in the phenotypic differences in patients with recognized chromosome duplication and deletion syndromes, which are usually attributed to the individual genotypic differences in the duplicated and/or deleted chromosome segments.

Developmental field defects: coming together of associations and sequences during blastogenesis

We report on two patients with an unusual combination of multiple congenital anomalies including holoprosencephaly, encephalocele, and additional defects commonly observed in the VACTERL and schisis "associations." One of the infants had a chromosome abnormality characterized by partial duplication and deletion of chromosome 18. VACTERL association was characterized recently as a primary developmental field defect (DFD) [Martínez-Frías et al., 1998: Am J Med Genet 76:291-296]. In some cases, sequences may also represent uncomplicated DFDs. We suggest that findings in both of these cases represent abnormalities of blastogenesis involving the primary field resulting in holoprosencephaly and VACTERL and schisis anomalies, and show that similar primary DFDs are causally heterogeneous.

Craniosynostosis, telecanthus, scalp hair abnormalities, and sensorineural deafness in two sibs

A sister and a brother with anomalous skull configuration, facial abnormalities, abnormal scalp hair growth, sensorineural hearing loss and, in the boy, proven craniosynostosis, severe mental retardation, and autism were reported in 1986 in an abstract by Hersh et al. We reexamined this family and here review the literature focusing on the major clinical findings, and suggest that their clinical manifestations may represent a previously unreported syndrome.

Fetal valproate syndrome and autism: additional evidence of an association

Autism has been described in association with a variety of medical and genetic conditions. We previously reported on a patient whose clinical phenotype was compatible with both fetal valproate syndrome (FVS) and autism. Here we present five additional patients with FVS and autism. In all five of our patients, there was evidence of cognitive deficits, manifestations of autism, and typical phenotypic characteristics of FVS. The association between this known teratogen and autism has both clinical and research implications.

Investigation of illness associated with exposure to hydrogen sulfide among Pennsylvania school students

During 1998, the Pennsylvania Department of Health received complaints about hydrogen sulfide odors believed to be associated with mushroom-composting operations in southeastern Pennsylvania. Many residents were concerned about possible illness in students attending an elementary school near the composting operations. In response, the department conducted health surveys during the spring and autumn at the exposed school and at a nearby control school. The surveys assessed whether exposures to hydrogen sulfide were associated with excess adverse health effects by comparing health effects among students from the exposed school with those among students from the control school. School nurses were trained to complete health questionnaires for the students. The state environmental agency measured daily ambient hydrogen sulfide concentrations at both schools. No consistent association was found between exposure to low levels of hydrogen sulfide and any adverse health effects. It was concluded that the students attending the elementary school near the mushroom-composting operations were not exposed to any significant public health hazard.

Case of partial duplication 2q3 with characteristic phenotype: rare occurrence of an unbalanced offspring resulting from a parental pericentric inversion

We report on a male infant with partial trisomy 2q (q34-->qter) resulting from a maternal pericentric inversion of chromosome 2 (p25. 2q34). The infant had clinical findings similar to the characteristic phenotype associated with a partial duplication of chromosome 2q3. Carriers of pericentric inversions of chromosome 2 have an increased risk of pregnancy loss but have only rarely been reported to have a liveborn offspring with an unbalanced chromosome constitution. This case further confirms the risks associated with a pericentric inversion of chromosome 2 and is the second report with manifestations of the trisomy 2q3 phenotype.

Neonatal progeroid (Wiedemann-Rautenstrauch) syndrome: report of five new cases and review

The neonatal progeroid syndrome (NPS), or Wiedemann-Rautenstrauch, is a rare autosomal recessive disorder comprised of generalized lipoatrophy except for fat pads in the suprabuttock areas, hypotrichosis of the scalp hair, eyebrows, and eyelashes, relative macrocephaly, triangular face, natal teeth, and micrognathia. We report on 5 new patients who demonstrate phenotypic variability and who represent the single largest series of NPS reported to date. Two of the patients are from an African-American kindred, an ethnic occurrence not reported previously. The fact that there are 2 pairs of sibs among the 5 patients further supports that NPS is an autosomal recessive condition. This report also includes a review of the previously reported 16 patients and compares them with the 5 new patients. Abnormalities in endocrine and lipid metabolism were found in 3 of 5 patients. Skeletal findings in 2 of our patients demonstrated some new findings as well as the typical radiological abnormalities previously noted in NPS. It is apparent, based on the 21 cases, that mild to moderate mental retardation is common in NPS. Long term follow-up of patients with NPS should provide more information relative to their ultimate psychomotor development. NPS is usually lethal by 7 months; however, on rare occasions, patients have survived into the teens. Our 3 surviving patients range in age from 16-23 months. Variability in the phenotype of NPS is clear; however, the phenotype remains distinct enough to allow a secure diagnosis.

Predictive value of fetal ultrasonography in the diagnosis of a lethal skeletal dysplasia

BACKGROUND

Certain ultrasonographic findings identified in a fetus suspected of having a skeletal dysplasia may be predictive of a lethal outcome.

METHODS

We evaluated 27 fetuses suspected of having a skeletal dysplasia using targeted ultrasonography between 16 and 31 weeks' gestation. Clinical examination and skeletal radiography were done after delivery.

RESULTS

A skeletal dysplasia was confirmed and a diagnosis established in all but one case. The skeletal dysplasia was lethal in 23 cases and, in each case, the outcome was accurately predicted prenatally; however, three of the infants survived several months. In 11 of the 23 cases (48%), the specific diagnosis was correctly determined before birth. Ultrasonographic findings not considered to reflect a lethal outcome, were accurately predicted in two other cases. In an additional two, sonographic examination suggested a lethal osteochondrodysplasia, though both survived. Findings consistent with a lethal skeletal dysplasia included a femur length < 1st centile, combined with either a bell-shaped thorax, decreased bone echogenicity, or both. Using these criteria provided a positive-predictive value for neonatal deaths of 80% (20/25), and 92% (23/25) if the three that died in infancy were included.

CONCLUSIONS

In the fetus suspected of having a skeletal dysplasia, certain findings on targeted ultrasonography frequently are predictive of a lethal outcome; the ability to predict this appears greatest when more than one of these abnormalities is present.

Molecularly proven hypochondroplasia with cloverleaf skull deformity: a novel association

We report on a case of cloverleaf skull deformity in a patient with hypochondroplasia, a disorder which has not been previously associated with this anomaly. Hypochondroplasia is a bone dysplasia caused by mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. Cloverleaf skull is a trilobar skull deformity which is etiologically and genetically heterogeneous and occurs in association with a number of disorders which result from mutations in the fibroblast growth factor receptor genes. Our patient demonstrated one of the common FGFR3 mutations identified in hypochondroplasia, a C-to-A change at nucleotide 1620 (C1620A) in the tyrosine kinase domain. The occurrence of a cloverleaf skull deformity appears to represent an example of variable expressivity in hypochondroplasia and suggests that additional factors other than a specific mutation can modify the phenotype in this disorder. In addition, identification of another FGFR mutation associated with cloverleaf skull further illustrates the genetic heterogeneity of this anomaly.

Changing phenotype in Floating-Harbor syndrome

We report on a girl with Floating-Harbor syndrome, trigonocephaly due to metopic suture synostosis, preauricular pit, hypoplastic thumb, subluxated radial head, and Sprengel deformity. A review suggests that trigonocephaly may be an important craniofacial manifestation in this syndrome that is recognizable in infancy. With time, this finding appears to become less noticeable, and the face develops a triangular shape, accentuated by a broad and bulbous nose.

The surgical management of the upper extremity anomalies associated with Du Pan syndrome

Du Pan syndrome is a rare condition comprising complex brachydactyly with fibular hypoplasia that is inherited in an autosomal recessive manner. This article describes experience gained through the management of four patients with this disorder. The surgical management of the upper limb abnormalities is discussed and a detailed timetable for their treatment is suggested.

Greig cephalopolysyndactyly syndrome: altered phenotype of a microdeletion syndrome due to the presence of a cytogenetic abnormality

A male had several features of Greig cephalopolysyndactyly syndrome (GCPS) and significant developmental delay. He was found to have a de novo chromosomal deletion of chromosome no. 7 involving p13; this resulted in loss of the zinc finger gene, GLI3, which is the candidate gene in this syndrome. Modification of the CGPS phenotype in a sporadic case emphasizes the importance of searching for a chromosomal origin of this autosomal dominant disorder. Detection of a chromosomal deletion in these patients may be associated with a poor prognosis from the standpoint of cognitive development, and the potential for other structural abnormalities not normally associated with GCPS.

A male with fetal valproate syndrome and autism

Fetal valproate syndrome (FVS) is characterized by minor craniofacial anomalies, major organ malformations, and developmental delay. We report on a patient who has a clinical phenotype compatible with both FVS and autism. The presence of an autistic disorder in a previously reported case of FVS and similar findings in our patient suggest that a relation between this known teratogen and autism may exist.

Expansion of the phenotype in Hennekam syndrome: a case with new manifestations

We report on a female with lymphedema, facial anomalies, intestinal lymphangiectasia, and moderate mental retardation consistent with the diagnosis of Hennekam syndrome. In addition, she had a number of other anomalies not previously described in this autosomal recessive disorder, including a congenital heart defect, atretic ear canals, vesicoureteral reflux, and rectal prolapse.

Anophthalmia, intracerebral cysts, and cleft lip/palate: expansion of the phenotype in oculocerebrocutaneous syndrome?

We report on a patient with multiple congenital anomalies including anophthalmia, cleft lip and palate, and central nervous system anomalies similar to the case reported by Leichtman et al. [1994: Am J Med Genet 50:39-41] and to oculocerebrocutaneous (Delleman) syndrome. Although the two cases and those with oculocerebrocutaneous syndrome may represent separate but overlapping entities, our patient and the case described by Leichtman et al. [1994: Am J Med Genet 50:39-41] may represent a more severe form of oculocerebrocutaneous syndrome.

XY gonadal dysgenesis associated with a multiple pterygium syndrome phenotype

Most phenotypic females with an XY male karyotype do not have significant extragenital anomalies; however, some patients with additional abnormalities have been described. We report on an individual with XY gonadal dysgenesis, mental retardation, microcephaly, growth retardation, and multiple pterygia. Although not previously reported, the possible relationship between these findings is discussed in the context of evident heterogeneity of XY gonadal dysgenesis.

A clinical and molecular study of mosaicism for trisomy 17

Trisomy 17 has never been reported in a live birth. We present a case of mosaic trisomy 17 in a male presenting with mental retardation, seizures, attention deficit hyperactivity and autistic disorders, hearing loss, growth retardation, microcephaly, and minor anomalies. Although peripheral blood lymphocyte chromosomes were normal, trisomy 17 was present in the skin fibroblasts. The percentage of abnormal cells appears to have increased from 18% in an initial skin biopsy at age 3 years 8 months to 80% at age 8 years 8 months. Molecular analysis using 13 highly polymorphic markers spanning the length of chromosome 17 demonstrated the extra chromosome 17 in the skin to be of paternal origin. Three alleles were never seen in the trisomic cell line, suggesting that the extra chromosome arose through a mitotic duplication error after conception. Uniparental disomy was excluded in the euploid blood sample. Although Smith-Magenis syndrome involves a deletion of proximal 17p, some of the clinical features of this mosaic trisomy 17 patient, such as decreased REM sleep and increased tolerance to pain, are suggestive of phenotypic features observed in Smith-Magenis syndrome. We speculate that there are dosage-sensitive genes located in 17p11.2 that produce these phenotypes for either deficiencies or over-expression of their gene products.

Mirror image duplication of the hands and feet: report of a sporadic case with multiple congenital anomalies

Mirror image duplication of the hands and feet is a rare entity. Based on 3 previous reports, findings include nasal abnormalities, dimelia of ulna and fibula, tibial hypoplasia and mirror image duplication of hands and feet. We report on a sporadic case in which mirror image duplication was associated with multiple congenital anomalies. Although these cases may represent variable expression of the same dominantly transmitted complex polysyndactyly syndrome, it is possible that mirror image duplication of the hands and feet is a manifestation common to a number of distinct clinical entities. During limb bud development, duplication and aberrant positioning of the zone of polarizing activity in relation to the apical ectodermal ridge may account for the anatomic abnormalities of the hands and feet in these patients.

The impact of major congenital malformations on mortality in a neonatal intensive care unit

Neonatal mortality due to congenital malformations or genetic disorders has not decreased despite a decrease in overall neonatal deaths with recent advances in medical technology. As a consequence, an increasing percentage of neonatal deaths is attributable to congenital malformations and genetic disorders. This study retrospectively reviewed neonatal deaths associated with congenital malformations over an 11-year period in the neonatal intensive care unit (NICU) at Kosair Children's Hospital, Louisville, Kentucky. Presently, congenital malformations are responsible for approximately 45% (range 32% to 61%) of deaths in the NICU with congenital heart disease, lethal genetic disorders, and pulmonary hypoplasia being the main contributors. Other major causes of neonatal death included extreme prematurity, respiratory disorders, necrotizing enterocolitis, sepsis, asphyxia, and primary pulmonary hypertension. It is important that clinicians are aware that improved survival is expected for most diseases because of technological advances, but that further significant reductions in neonatal mortality will depend on genetic counseling and prevention of congenital malformations.

De novo 1;10 balanced translocation in an infant with thanatophoric dysplasia: a clue to the locus of the candidate gene

A female infant with thanatophoric dysplasia was found to have a de novo translocation involving chromosomes 1 and 10. The chromosome abnormality may represent an important clue in identifying the locus for the candidate gene responsible for this lethal skeletal dysplasia.

A non-trophoblastic tumor co-existing with a triploid fetus

Non-trophoblastic neoplasms are the most frequent, benign tumors of the placenta, occurring in approximately 1% of all placentas examined. A case is described of a 24-year-old woman who presented with severe, early-onset pre-eclampsia, high human chorionic gonadotropin (hCG) levels, and a triploid fetus and who was found to have a small choriohemangioma. The woman, gravida 2 para 1, was referred to our hospital for perinatal evaluation. The fetus, gestational age 18 weeks 3 days, had fetal growth restriction with multiple congenital anomalies. The fetal karyotype was 69,XXY. Compared with the normal range for this gestational age, the beta-hCG level was significantly elevated (1,054,000 mIU/ml) as was the maternal serum alpha-feto-protein measurement (539.1 ng/ml). Sonographically, the placenta appeared hydropic, irregularly shaped, and gelatinous. A suction dilatation and evacuation under sonographic guidance was performed. Histological examination of placental tissue revealed hydropic degeneration of the chorionic villi. The specific histological features of a partial molar pregnancy were not present. However, there were changes consistent with a choriohemangioma. Flow cytometric DNA analysis performed on formalin-fixed, paraffin-embedded tissue blocks of placenta showed triploidy. Immunohistochemical staining with human placental alkaline phosphatase was consistent with a hydropic degeneration pattern. We conclude, first, that triploidy does not always imply the presence of a partial mole. Second, the dictum, that pre-eclampsia, if it occurs under 20 weeks' gestation, must be associated with a molar pregnancy, may not hold when placental aneuploidy is present. Although the findings in this pregnancy could have been incidental, there may be an association between a choriohemangioma and polyploidy.

Microcephalic osteodysplastic dysplasia

We present two patients with a distinct facial phenotype, short stature, brachydactyly, clubfoot deformities, cataracts, microcephaly, and normal intelligence. Similar radiographic abnormalities of the spine, long bones, hands, and feet were noted. These patients are similar to 2 males previously described by Saul and Wilson [1990: Am J Med Genet 35:388-393]. These 4 patients appear to have a unique skeletal dysplasia characterized by microcephaly, distinct facial phenotype, multisystem abnormalities, and short stature of postnatal onset.

The role of genetic counseling in visually impaired adolescents

The presence of genetic disorders in a high percentage of adolescents with significant visual impairments emphasizes the important role that genetic counseling can play in this population. However, its intended goals have been controversial. Responses to structured interviews about genetic counseling services from three groups of former students from the Kentucky School for the Blind were compared. One group consisted of students who had received genetic counseling; another, of students who had declined it; and a third, of students who had graduated before the service was available. In all groups, genetic counseling was viewed as a valuable service which would have been pursued by the majority of those who did not have the opportunity to receive it, and by many of those who refused it initially. Although genetic counseling did little to enhance knowledge of the cause of the specific visual impairment, it appeared to be useful in providing information regarding the risk of visual impairment in future offspring. A relatively high rate of unplanned pregnancies was noted in the group who had refused genetic counseling. The significance of this observation is uncertain. One interpretation is that the group refusing genetic counseling may have consisted of individuals who had fewer concerns as adolescents about family planning issues. These observations suggest that it may be appropriate to recommend to adolescents with significant visual impairments to defer childbearing until independent life experiences are accumulated outside the school setting. Then, prior to considering childbearing, genetic counseling should be sought.

Identification of two single base substitutions in the UGT1 gene locus which abolish bilirubin uridine diphosphate glucuronosyltransferase activity in vitro

Accumulating evidence indicates that mutations in the human UGT1 gene locus abolish hepatic bilirubin UDP-glucuronosyltransferase activity and cause the subsequent accumulation of bilirubin to toxic levels in patients with Crigler-Najjar type 1 (CN-I). Genetic and biochemical criteria are required to link CN-I with mutations in UGT1. Here we present analysis of mutations at the UGT1 locus in three individuals that were clinically diagnosed with CN-I (two related and one unrelated). Each patient carries a single base substitution that alters conserved residues in the transferase enzyme molecule, serine to phenylalanine at codon 376 and glycine to glutamic acid at codon 309. Each was homozygous for the defect as demonstrated by sequencing and RFLPs. Mutant cDNAs, constructed by site-directed mutagenesis, inserted into expression vectors, and transfected into COS-1 cells, supported the synthesis of the bilirubin transferase protein but only cells transfected with the wild-type cDNA expressed bilirubin UDP-glucuronosyltransferase activity. The data provide conclusive evidence that alterations at Gly 309 and Ser 376 are the genetic basis for CN-I in these families. These results suggest that the two codons, located in conserved regions of the molecule, are part of the active site of the bilirubin enzyme.

Urethral obstruction sequence and lower limb deficiency: evidence for the vascular disruption hypothesis

We reviewed five unreported examples and 23 previously reported cases of urethral obstruction sequence with associated lower limb deficiency. There was no evidence of amniotic bands or exposure to vasoactive drugs during pregnancy in any case. In three infants a gangrenous lesion at the distal part of the affected leg was found; in another three infants, necrotic tissue was noted in the stump of the affected leg. This type of lesion can be explained only on a vascular ischemic basis. In five cases, signs of compression of the external iliac artery by the grossly distended bladder, by grossly distended ureters, or both were found. A vascular disruption in the territory of the external iliac artery caused by compression by the distended urinary tract is the proposed mechanism for the associated limb deficiency.

Trichothiodystrophy and associated anomalies: a variant of SIBIDS or new symptom complex?

Trichothiodystrophy is characterized by sparse, short, sulfur-deficient hair. Numerous symptom complexes have been described in which the hair abnormality represents a constant feature. We report a boy with trichothiodystrophy, ichthyotic skin changes, onychodystrophy, chronic neutropenia, osteosclerosis, hypothyroidism, nystagmus, growth and mental retardation, and microcephaly, who developed a progressive encephalopathy with ataxia and optic atrophy at 2.5 years of age. In addition to a deficient cystine level identified on a hair sample, a disturbance in the composition of other amino acids was present. Although features were reminiscent of osteosclerosis, ichthyosis, brittle hair due to trichothiodystrophy, impaired intelligence, decreased fertility, and short stature (SIBIDS) and could represent a variant of this disorder, findings in our patient may reflect a new trichothiodystrophy symptom complex that carries a poor prognosis for survival beyond childhood.

Aplasia cutis congenita, cleft palate, epidermolysis bullosa, and ectrodactyly: a new syndrome?

Aplasia cutis congenita (ACC) is a skin disorder in which localized or widespread areas of skin are absent at birth. It has been associated with numerous anomalies and recognizable syndromes. We report a newborn infant with ACC of the scalp, multiple facial abnormalities including cleft palate but not cleft lip, hypoplasia of the distal phalanges of the hands, ectrodactyly of the feet, and epidermolysis bullosa of the extremities and lower trunk. Although this patient had some features that overlapped with ectrodactyly-ectodermal dysplasia-clefting syndrome, the absence of cleft lip and presence of additional skin abnormalities made that diagnosis unlikely. This could represent a newly recognized syndrome of numerous malformations in which ACC is associated with a constellation of previously undescribed structural anomalies.

Natal teeth in monozygotic twins with Van der Woude syndrome

The second monozygotic twin pair concordant for Van der Woude syndrome is reported. Clinical manifestations of this autosomal dominant clefting syndrome included bilateral lower lip pits, cleft lip, and cleft palate. Both sibs were found to have a natal tooth. No other cases of Van der Woude syndrome with this feature have been described previously. It is uncertain whether the presence of a natal tooth in this instance represents a low-frequency association of this disorder. However, it appears more likely that its occurrence was incidental, since natal teeth have been reported before in twin pairs as an isolated finding.

Risk of malignancy in Sotos syndrome

A questionnaire survey identified a possibly increased risk of malignancy for patients with Sotos syndrome. Because the sites and types of neoplasm found in these patients vary, no routine screening except for periodic clinical evaluation seems feasible.