Mutations in JARID1C are associated with X-linked mental retardation, short stature and hyperreflexia.

BACKGROUND: Mutations in the JARID1C (Jumonji AT-rich interactive domain 1C) gene were recently associated with X-linked mental retardation (XLMR). Mutations in this gene are reported to be one of the relatively more common causes of XLMR with a frequency of approximately 3% in males with proven or probable XLMR. The JARID1C protein functions as a histone 3 lysine 4 (H3K4) demethylase and is involved in the demethylation of H3K4me3 and H3K4me2. METHODS: Mutation analysis of the JARID1C gene was conducted in the following cohorts: probands from 23 XLMR families linked to Xp11.2, 92 males with mental retardation and short stature, and 172 probands from small XLMR families with no linkage information. RESULTS: Four novel mutations consisting of two missense mutations, p.A77T and p.V504M, and two frame shift mutations, p.E468fsX2 and p.R1481fsX9, were identified in males with mental retardation. Two of the mutations, p.V504M and p.E468fsX2, are located in the JmjC domain of the JARID1C gene where no previous mutations have been reported. Additional studies showed that the missense mutation, p.V504M, was a de novo event on the grandpaternal X chromosome of the family. Clinical findings of the nine affected males from the four different families included mental retardation (100%), short stature (55%), hyperreflexia (78%), seizures (33%) and aggressive behaviour (44%). The degree of mental retardation consisted of mild (25%), moderate (12%) and severe (63%). CONCLUSION: Based on the clinical observations, male patients with mental retardation, short stature and hyperreflexia should be considered candidates for mutations in the JARID1C gene.

Multiple mechanisms are implicated in the generation of 5q35 microdeletions in Sotos syndrome.

BACKGROUND: Sotos syndrome is characterised by learning difficulties, overgrowth, and a typical facial appearance. Microdeletions at 5q35.3, encompassing NSD1, are responsible for approximately 10% of non-Japanese cases of Sotos. In contrast, a recurrent approximately 2 Mb microdeletion has been reported as responsible for approximately 50% of Japanese cases of Sotos. METHODS: We screened 471 cases for NSD1 mutations and deletions and identified 23 with 5q35 microdeletions. We investigated the deletion size, parent of origin, and mechanism of generation in these and a further 10 cases identified from published reports. We used "in silico" analyses to investigate whether repetitive elements that could generate microdeletions flank NSD1. RESULTS: Three repetitive elements flanking NSD1, designated REPcen, REPmid, and REPtel, were identified. Up to 18 cases may have the same sized deletion, but at least eight unique deletion sizes were identified, ranging from 0.4 to 5 Mb. In most instances, the microdeletion arose through interchromosomal rearrangements of the paternally inherited chromosome. CONCLUSIONS: Frequency, size, and mechanism of generation of 5q35 microdeletions differ between Japanese and non-Japanese cases of Sotos. Our microdeletions were identified from a large case series with a broad range of phenotypes, suggesting that sample selection variability is unlikely as a sole explanation for these differences and that variation in genomic architecture might be a contributory factor. Non-allelic homologous recombination between REPcen and REPtel may have generated up to 18 microdeletion cases in our series. However, at least 15 cannot be mediated by these repeats, including at least seven deletions of different sizes, implicating multiple mechanisms in the generation of 5q35 microdeletions.

Partial urorectal septum malformation sequence: a report of 25 cases.

We have identified 25 cases with what we are calling the partial urorectal septum malformation (URSM) sequence, which were seen in our institution over the past 27 years. The partial URSM sequence is defined as a single perineal/anal opening that drains a common cloaca in combination with an absent (imperforate) anus. In the 25 patients reported here, the partial URSM sequence was more common in females, with a female to male ratio of 18 to 7. Ambiguous genitalia were common in both sexes. Internal pelvic structures typically showed a cloaca with the bladder and rectum (and vagina in females) coalescing into a common canal that connected to the external surface in the perineal or anal area. Abnormalities of the internal genitalia were also common, with 12 females having a bifid or septate vagina and 11 having a bicornuate uterus. Renal anomalies were frequent in both sexes, with 10 of 25 patients having unilateral cystic renal dysplasia and 7 of 25 patients having unilateral renal agenesis. Twenty-one of 25 patients survived long term. By definition, the partial URSM sequence is a milder expression of the full URSM sequence, which is defined as having no perineal or anal openings and is typically associated with an internal cloaca. The URSM spectrum, which encompasses the partial and full URSM sequences, is believed to be caused by abnormalities of septation of the primitive cloaca. The URSM spectrum is distinct from the VATER association and conditions caused by sex hormone abnormalities, such as congenital adrenal hyperplasia.

Weaver syndrome with neuroblastoma and cardiovascular anomalies.

We report on an infant with Weaver syndrome, neoplasia and cardiovascular anomalies. Stage 4S neuroblastoma underwent spontaneous resolution. Three neoplasms have been reported in Weaver syndrome: another stage 4S neuroblastoma [Muhonen and Menezes, 1990: J Pediatr 116:596-599], an ovarian endodermal sinus tumor [Derry et al., 1999: J Med Genet 36:725-728], and a sacrococcygeal teratoma [Kelly et al., 2000: Am J Med Genet 95:492-495]. No case was associated with cardiovascular anomalies. Our patient had VSD and PDA, and although several other patients with Weaver syndrome have had cardiovascular anomalies, they were shown not to have neoplasia.

Distal 13q Deletion Syndrome and the VACTERL association: case report, literature review, and possible implications.

We present a case of a child with del(13) (q31.1qter), VACTERL association, and penoscrotal transposition. Deletion of the distal long arm of chromosome 13 is associated with variable phenotypes. These phenotypes are divided into three clusters; each cluster represents a specific deleted segment of 13q. Individuals with deletions of a critical region at 13q32 have multiple congenital malformations that include components of the VACTERL association. Our patient had all six manifestations of VACTERL association. In addition, he had complete penoscrotal transposition, a unique malformation reported rarely in VACTERL association and only twice previously in deletion of distal 13q. We reviewed all reported cases of distal 13q deletions to date. Of these 137 patients, 15 could be classified into the VACTERL association. Ours was the only patient with distal 13q deletion and all VACTERL association features and also the only one with tracheoesophageal fistula. Neither holoprosencephaly nor the other central nervous system malformations that have been seen in individuals with distal 13q deletions were apparent in him. The patient presented here appears to be unique among individuals with distal 13q deletion. His cluster of malformations strengthens the argument that distal 13q deletion is a cause for VACTERL association, and that this causal relationship implies a syndromic form of VACTERL. In addition, this case and those ascertained from the literature suggest that penoscrotal transposition should be considered part of both the distal 13q-deletion syndrome and some forms of VACTERL association.

Familial choanal atresia with maxillary hypoplasia, prognathism, and hypodontia.

We report on two sibs and a cousin with bilateral choanal atresia. At 2 months, one sib died of complications following surgical correction of her defects. We evaluated her brother and cousin at age 7 and 9 years, respectively. Both had a tall forehead, maxillary hypoplasia, prognathism, and absence of certain deciduous and permanent teeth. Psychomotor development was appropriate for age. Roentgenocephalometric analyses of several relatives showed that one grandfather of these children and two of the five uncles and aunts also had maxillary hypoplasia and/or prognathism. To our knowledge, this condition has not been described previously and may represent a newly recognized autosomal dominant condition with incomplete penetrance and variable expressivity caused by a defect of neural crest development.

Hypogonadism and CHARGE association.

The G of the CHARGE association represents genital hypoplasia, which is typically recognized only in males (micropenis/cryptorchidism). The cause of genital hypoplasia in this disorder has not been determined. We now report the cases of nine individuals with CHARGE association and hypogonadotropic hypogonadism, manifested by hypogenitalism and gonadotropins at or below minimal detectable levels at ages when these hormones should be readily measurable. We suggest that central hypogonadism is responsible not only for the genital hypoplasia in male patients but also for the lack of secondary sexual development in patients of both sexes. Since hypogonadotropic hypogonadism appears to be the usual cause of genital and pubertal abnormalities in CHARGE association, measurement of serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations in infants up to 2-3 months of age who are suspected of having this disorder could help establish the diagnosis. Determination of serum LH and FSH concentrations in teenagers with CHARGE association could result in early diagnosis of hypogonadotropic hypogonadism, allowing for treatment of hormonal deficiencies and minimization of potential secondary psychosocial and medical problems.

Exclusion of the branchio-oto-renal syndrome locus (EYA1) from patients with branchio-oculo-facial syndrome.

In addition to craniofacial, auricular, ophthalmologic, and oral anomalies, the distinctive phenotype of the branchio-oculo-facial (BOF) syndrome (MIM 113620) includes skin defects in the neck or infra/supra-auricular region. These unusual areas of thin, erythematous wrinkled skin differ from the discrete cervical pits, cysts, and fistulas of the branchio-oto-renal (BOR) syndrome (MIM 113650). Although the BOF and BOR syndromes are sufficiently distinctive that they should not be confused, both can be associated with nasolacrimal duct stenosis, deafness, prehelical pits, malformed pinna, and renal anomalies. Furthermore, a reported father and son [Legius et al., 1990, Clin Genet 37:347-500] had features of both conditions. It was not clear whether they had an atypical presentation of either BOR or BOF syndrome, or represented a private syndrome. In light of these issues, we selected the BOR locus (EYA1) as a possible gene mutation for the BOF syndrome. In five BOF patients, there were no mutations detected in the EYA1 gene, suggesting that it is not allelic to the BOR syndrome.

Mild autosomal dominant hypophosphatasia: in utero presentation in two families.

We describe four pregnancies in two families in which mild hypophosphatasia, apparently transmitted as an autosomal dominant trait, manifested in utero as severe long bone bowing. Postnatally, there was spontaneous improvement of the skeletal defects. Recognition of this presentation for hypophosphatasia by family investigation and assessment of the fetal skeleton for degree of ossification and chest size using ultrasonography is important. The prognosis for this condition is considerably better than for more severe forms of hypophosphatasia and for many other disorders that cause skeletal defects with long bone bowing in utero.

Bone mineral density and laboratory evaluation of a type II autosomal dominant osteopetrosis carrier.

Type II autosomal dominant osteopetrosis (ADO2) is an inherited disorder characterized by increased skeletal mass and characteristic abnormalities evident on radiography. Although previous investigators have described nonpenetrant individuals (carriers), it is not known whether carriers manifest subtle abnormalities. We hypothesized that ADO2 carriers would have an abnormality of osteoclast function that would lead to changes in bone mineral density (BMD), in serum tartrate-resistant acid phosphatase (TRAP), or in creatine kinase isoenzyme BB (CK-BB) levels that would permit carrier recognition. We identified a female carrier in a well-established ADO2 family and measured BMD, serum TRAP, and CK-BB concentrations. She had normal BMD, serum TRAP, and CK-BB concentrations. Thus, these measurements cannot be used to exclude carrier status in individuals who are seen for genetic counseling. However, measurements in other asymptotic carriers are necessary before concluding that these measurements are normal in all or most nonpenetrant individuals.

De novo 10q22 interstitial deletion.

We describe a 4 month old male with a de novo interstitial deletion of chromosome 10q22. His clinical features included growth deficiency, developmental delay, ocular hypertelorism, posteriorly rotated ears, retrognathia, and fifth finger clinodactyly. He later developed dental lamina cysts of the alveolar ridge. To our knowledge, this is the first reported case of an interstitial deletion of 10q22.

Genitourinary anomalies in the CHARGE association.

PURPOSE: We identified the incidence and types of genital and urinary anomalies, and established a plan for evaluating the urinary system in the CHARGE association. MATERIALS AND METHODS: We retrospectively reviewed the charts of 32 patients in whom the CHARGE association was diagnosed. RESULTS: Of the 32 patients identified 22 (69%) had genitourinary abnormalities. Genital anomalies, including micropenis, penile agenesis, hypospadias, chordee, cryptorchidism, a bifid scrotum, atresia of the uterus, cervix and vagina, and hypoplastic labia majora, labia minora and clitoris, were present in 18 patients (56%). Of the 24 patients who underwent renal ultrasound 10 (42%) were diagnosed with urinary tract anomalies including a solitary kidney, hydronephrosis, renal hypoplasia and duplex kidneys. Further evaluation revealed vesicoureteral reflux, neurogenic bladder secondary to spinal dysraphism, nephrolithiasis, ureteropelvic junction obstruction and a nonfunctioning upper pole in both duplex kidneys. CONCLUSIONS: There is a high incidence of genitourinary anomalies in the CHARGE association. Because of this high incidence of anomalies, patients with this condition should undergo a careful genitourinary evaluation, including renal and bladder ultrasound, and voiding cystourethrography screening.

Weaver syndrome: autosomal dominant inheritance of the disorder.

Weaver syndrome (WS), a condition first described in 1974 by Weaver et al., consists of macrosomia, advanced skeletal age, characteristic pattern of facial and radiographic anomalies, and contractures. Although there have been three reports of close relatives (sibs or both parent and offspring) affected with this condition, the syndrome generally occurs sporadically, and the recurrence risk in sporadic cases appears to be low. We report here on a family in which the propositus and his sister were born with the facial phenotype, club feet, and macrosomia characteristic of WS. Their father had macrosomia and macrocephaly as an adult, and childhood photos show clearly that he has WS. Two sisters of the propositus have had normal growth and development. The syndrome in this family appears to be inherited in an autosomal dominant fashion.

49,XXXXY: a distinct phenotype. Three new cases and review.

Over 100 cases of 49,XXXXY syndrome have been published to date. Classic findings include radioulnar synostosis, hypogonadism, and mental retardation. The majority of reported cases have not distinguished the 49,XXXXY syndrome from Klinefelter syndrome (47,XXY), and these patients are frequently labelled as having Klinefelter syndrome or as being a "Klinefelter variant." Because of distinct clinical features, we delineate the 49,XXXXY syndrome as separate from Klinefelter syndrome, and emphasise the prevalence of congenital heart defects. We also report three new cases of 49,XXXXY syndrome and briefly discuss patient management.

Livedo reticularis, developmental delay and stroke-like episode in a 7-year-old male.

Livedo reticularis is a vascular abnormality of the skin resulting in an erythematous reticular rash. The combination of livedo reticularis and stroke-like episodes in adults is known as Sneddon syndrome [Sneddon, IB (1965). Br J Dermatol 77:180-188]. A similar combination of stroke-like episodes and livedo reticularis has been reported to occur in children [Baxter P et al. (1993). Dev Med Child Neuro 35:917-926]. We present here a 7-year-old male with congenital livedo reticularis, obesity, developmental delay, stroke-like episode, hypertension and cystic kidneys. We summarize our patient's findings and family history, and compare his disorder to other possibly related conditions.

Lethal syndrome of skeletal dysplasia and progressive central nervous system degeneration.

We describe 3 sibs (2 males and 1 female) with multiple congenital anomalies, poor growth, seizures, and progressive central nervous system (CNS) degeneration leading to death in infancy. Radiographic changes in all 3 were similar, and included moderate shortness of long bones, platyspondyly, and hypoplastic pelvis. Autopsies showed diffuse encephalomyelopathy and enlargement of the lateral and third ventricles. Lysosomal enzyme activities were normal. Collagen type II analysis on 2 of the sibs indicated normal collagen. Chromosomes appeared normal. Even though the radiographic and chondroosseous morphologic findings in these sibs have a certain similarity to Dyggve-Melchior-Clausen syndrome, their clinical course does not fit this condition. These infants appear to represent a new syndrome of bone dysplasia and CNS degeneration inherited as an autosomal recessive trait.

Molecular cytogenetic identification of four X chromosome duplications.

Four cases with previously unidentified X-chromosome abnormalities were studied by standard cytogenetic techniques and FISH in order to demonstrate the origin of the extra segment on the abnormal X chromosomes. All cases were identified as X-chromosome duplications by using a chromosome-specific painting probe. Application of appropriate locus-specific DNA probes as an adjunct to GTG- and RBG-banding proved useful in defining the breakpoints and the extent of the duplications. Although the duplicated X chromosome in female cases was selectively inactivated, as demonstrated by its late-replicating pattern, abnormal clinical findings were manifested in 3 female patients.

Urorectal septum malformation sequence: report of thirteen additional cases and review of the literature.

We present the findings of 13 additional cases of the urorectal septum malformation (URSM) sequence, and review the literature. The URSM sequence consists of ambiguous genitalia concurrent with absence of perineal and anal openings. The sex ratio of the 13 new cases was 7 males to 6 females and from the literature 21 males and 28 females. In addition, 11 of the 13 new cases had anorectal atresia with 5 of the cases also having partial agenesis of the colon. Bilateral renal agenesis was present in 3 of the 13 cases, unilateral renal agenesis occurred in 6, and dysplastic kidneys were found in 10. The URSM sequence is a lethal condition with long-term survival reported in only 3 of a total of 62 literature and new cases. Recurrence of this condition has not been reported.

Oculo-auriculo-vertebral spectrum and the CHARGE association: clinical evidence for a common pathogenetic mechanism.

We describe two infants with features of both the oculo-auriculo-vertebral spectrum (OAVS) and the CHARGE association (CA). Both patients are more severely affected than the typical patient with the OAVS. Each has facial asymmetry, mandibular hypoplasia, ear abnormalities, hearing impairment, microphthalmia, heart defects, and developmental delay. They also have features that are not characteristic of either OAVS or CA including torticollis, plagiocephaly, and heminostril. Based on the findings of these patients and other reported in the literature, there appears to be a significant overlap of features between OAVS and CA, and we suggest that these conditions in fact may be produced by the same pathogenetic mechanism. One such mechanism to explain the overlap of these disorders is that both conditions are part of the axial mesodermal spectrum, and represent a dysblastogenetic process. This mechanism may also explain the presence of some of the additional features not normally seen in OAVs and CA but seen in these two infants.