Agenesis of corpus callosum in three sibs

Summary We report on a rare familial cases with complete agenesis of the corpus callosum found in three sibs, in which autosomal recessive mode of inheritance was suggested.     

Agenesis of the corpus callosum and hepatoblastoma

Agenesis of the corpus callosum is a congenital brain malformation that can occur in isolation or as a component of a congenital syndrome. Hepatoblastoma (HB) is a rare tumor that comprises two thirds of primary hepatic neoplasms in children and adolescents. Up to 20% of children with HB have associated congenital anomalies. In addition to defined genetic syndromes such as Familial Adenomatous Polyposis, Beckwith–Wiedemann syndrome, Trisomy 13, and Trisomy 18, HB is significantly associated with kidney/bladder abnormalities. We present two children with multiple congenital anomalies, including agenesis of the corpus callosum, who were subsequently diagnosed with HB. Review of the literature revealed two patients with clinically‐diagnosed Aicardi syndrome and HB. Due to the rarity of both agenesis of the corpus callosum and HB, this is likely a true association. Further investigation into the underlying genetic and molecular basis of this probable association is warranted.     

Agenesis of the corpus callosum in a mother and son

Most reported familial cases of agenesis of the corpus callosum have followed either an autosomal recessive or an X-linked recessive pattern of inheritance. To the best of our knowledge, there is only one previous report of a family showing clear-cut autosomal dominant inheritance. We present the second such family, among whom a mother and her son had moderately severe coordination problems and low-normal intelligence. We suggest that agenesis of the corpus callosum, when transmitted as an autosomal dominant trait, is clinically characterized by a relatively milder phenotype than that occurring when inheritance is either autosomal or X-linked recessive and may be more common than has been thought. Am. J. Med. Genet. 69:152–154, 1997. © 1997 Wiley-Liss, Inc.     

Agenesis of the corpus callosum and macrocephaly in siblings

A brother and sister with developmental delay, relative macrocephaly and agenesis of the corpus callosum are described. The brother also had unilateral cerebellar hypoplasia and malrotation of the large bowel. Published cases of familial agenesis of the corpus callosum are reviewed and the value of ultrasonography in demonstrating agenesis of the corpus callosum in the neonate is emphasised.     

Corpus callosum agenesis, severe mental retardation, epilepsy, and dyskinetic quadriparesis due to a novel mutation in the homeodomain of ARX

We report on a patient with agenesis of the corpus callosum (ACC), severe mental retardation, infantile spasms and subsequent intractable epilepsy, spastic/dyskinetic quadriparesis, severe limb contractures, and scoliosis. This complex, newly described phenotype, is due to a novel non-conservative missense mutation in the ARX homeodomain (c.1072A>T; p.R358W), inherited from the unaffected mother. Differently from previously reported non-conservative mutations falling within the same domain, p.R358W did not cause XLAG. It is therefore possible that differences in clinical manifestations between our patient and those with XLAG, are related to the different position of the amino acid substitution in the homeodomain, or to the different chemical properties introduced by the substitution itself. To test the hypothesis that the patient's mother was asymptomatic because of non-random X chromosome inactivation (XCI), we performed DNA methylation studies of the human androgen receptor gene, demonstrating skewing of the XCI ratio (85:15). The complex phenotype described here combines different traits that had previously been linked to various ARX mutations, including conservative missense mutations in the homeodomain and expansion in the first ARX polyalanine tract and contributes to the expanding pleiotropy associated with ARX mutations.     

“C” Trigonocephaly syndrome: Report of a child with agenesis of the corpus callosum and tetralogy of Fallot,and review

We report on a new case of the Opitz “C” trigonocephaly syndrome. Our patient had agenesis of the corpus callosum, an anomaly seen only twice previously, and tetralogy of Fallot, described only once before. A review shows that a combination of conotruncal heart defects and midline brain anomalies characterizes patients with this entity. © 1995 Wiley-Liss, Inc.     

Frontonasal dysplasia, lipoma of the corpus callosum and tetralogy of Fallot

Meguid NA. Frontonasal dysplasia, lipoma of the corpus callosum and tetralogy of Fallot.
Clin Genet 1993: 44: 95–97. © Munksgaard, 1993
A 6-year-old Egyptian boy with frontonasal dysplasia (FND) and lipoma of the corpus callosum associated with tetralogy of Fallot is reported. The main features were severe hypertelorism, downward slanted palpebral fissures, bilateral epicanthal folds, a grossly deformed nose with notched alae nasi, absent nasal tip and long philtrum. A computerized tomography (CT) scan of the brain showed cerebral atrophy and lipoma of the corpus callosum. While marked neurological symptoms have been reported in cases with lipoma of the corpus callosum in the absence of FND, the present case and previous reports showed minor neurological alterations when lipoma of the corpus callosum was associated with FND. From the findings in this case and previous reports, it is possible to conclude that lipoma of the corpus callosum associated with FND is always located in the anterior part of the corpus callosum. The etiology of FND remains uncertain. While multifactorial inheritance has been proposed, parental consanguinity with young parental age in the present case cannot exclude autosomal recessive inheritance.     

Partial agenesis of the corpus callosum, hippocampal atrophy, and stable intellectual disability associated with Roifman syndrome

In 2006, we reported the cognitive and behavioral phenotype of the seventh case of Roifman syndrome (OMIM 300258). Aged 11 years 6 months, the patient displayed significant intellectual disability with proportionate impairments in attentional-executive, memory, and visuo-spatial abilities despite appearing socially "able." This discrepancy may be explained by good social-emotional skills masking his intellectual disability, by decline in cognitive abilities over time, or by unusual neuroradiological abnormalities not previously examined in Roifman syndrome. Here, we present results from a structural MRI scan, neurocognitive evaluations repeated 2 and 5 years post-baseline and assessments of face and emotional processing. The MRI revealed partial agenesis of the corpus callosum, bilateral hypoplastic hippocampi but bilaterally intact amygdala. No evidence was found for decline in the patient's neurocognitive profile. Emotional processing data indicated an age-appropriate pattern of reactivity to emotional stimuli and preserved facial identity recognition abilities, but impairments in recognition of negative facial expressions. The results confirmed a stable pattern of intellectual disability, and indicated that Roifman syndrome may be associated with major structural neuro-anatomical abnormalities. We suggest that the relative strengths in emotion and face processing are consistent with the patient's apparently able social behavior, and with intact amygdalar function.     

Agenesis of the corpus callosum and gray matter heterotopia in three patients with constitutional mismatch repair deficiency syndrome

Constitutional mismatch repair deficiency (CMMR-D) syndrome is a rare inherited childhood cancer predisposition caused by biallelic germline mutations in one of the four mismatch repair (MMR)-genes, MLH1, MSH2, MSH6 or PMS2. Owing to a wide tumor spectrum, the lack of specific clinical features and the overlap with other cancer predisposing syndromes, diagnosis of CMMR-D is often delayed in pediatric cancer patients. Here, we report of three new CMMR-D patients all of whom developed more than one malignancy. The common finding in these three patients is agenesis of the corpus callosum (ACC). Gray matter heterotopia is present in two patients. One of the 57 previously reported CMMR-D patients with brain tumors (therefore all likely had cerebral imaging) also had ACC. With the present report the prevalence of cerebral malformations is at least 4/60 (6.6%). This number is well above the population birth prevalence of 0.09–0.36 live births with these cerebral malformations, suggesting that ACC and heterotopia are features of CMMR-D. Therefore, the presence of cerebral malformations in pediatric cancer patients should alert to the possible diagnosis of CMMR-D. ACC and gray matter heterotopia are the first congenital malformations described to occur at higher frequency in CMMR-D patients than in the general population. Further systematic evaluations of CMMR-D patients are needed to identify possible other malformations associated with this syndrome.     

Associated anomalies in cases with agenesis of the corpus callosum

Agenesis of corpus callosum (ACC) is an uncommon congenital anomaly, its etiology is unclear and its pathogenesis is controversial. Cases with ACC often have other non‐ACC associated congenital anomalies. The purpose of this study was to assess the prevalence and the types of these associated anomalies in a defined population. The associated anomalies in cases with ACC were collected in all live births, stillbirths, and terminations of pregnancy during 29 years in 387,067 consecutive births in the area covered by our population‐based registry of congenital malformations. Of the 99 cases with ACC, representing a prevalence of 2.56 per 10,000, 73 (73.7%) had associated anomalies. There were 16 (16.2%) cases with chromosomal abnormalities, and 13 (13.2%) nonchromosomal recognized dysmorphic conditions including syndromes two each: Aicardi, Dandy–Walker, and fetal alcoholism. Forty‐four (44.4%) of the cases had nonsyndromic multiple congenital anomalies (MCA). Anomalies in the musculoskeletal, the urogenital, the central nervous, the cardiovascular, and the digestive systems were the most common other anomalies in the cases with MCA. The anomalies associated with ACC could be classified into a recognizable malformation syndrome in 29 out of the 73 cases (39.7%) with associated anomalies. This study included special strengths: it is population‐based, each affected child was examined by a geneticist, all elective terminations were ascertained, and the surveillance for anomalies was continued until 2 years of age. In conclusion the overall prevalence of associated anomalies, three of four cases, emphasizes the need for a screening for other anomalies in cases with ACC.     

X-linked lissencephaly with absent corpus callosum and ambiguous genitalia

Lissencephaly has been described in over 10 distinct malformation syndromes. Recently, we have recognized 5 children from four unrelated families with an almost identical disorder comprising lissencephaly with a posterior-to-anterior gradient and only moderate increase in thickness of the cortex, absent corpus callosum, neonatal-onset epilepsy, hypothalamic dysfunction including deficient temperature regulation, and ambiguous genitalia in genotypic males. Our observation of 5 affected males in one of these families is consistent with an X-linked pattern of inheritance. However, it differs in many regards from the X-linked form of isolated lissencephaly sequence that is associated with mutations of the XLIS (DCX) gene. Therefore, we propose that this disorder comprises a new X-linked malformation syndrome, which we refer to as X-linked lissencephaly with ambiguous genitalia (XLA-G). Am. J. Med. Genet. 86:331–337, 1999. © 1999 Wiley-Liss, Inc.     

胎儿胼胝体发育不全的磁共振成像与超声检查对比研究

目的:本研究以磁共振成像(MRI)为参考标准,评价了产前超声检查诊断胎儿胼胝体发育不全(ACC)的能力,并评估了MR图像的神经解剖学特征。方法:超声检查发现胎儿神经发育异常可能的孕妇共计263例,对其胎儿头颅MR图像进行评估。结果:胎儿MRI累计诊断25例ACC,其中24例未被超声检查发现。超声检查诊断ACC的准确性为91%。另外,MRI发现了3例具有相似形态学特征的ACC,即非典型泪滴征。结论:与超声检查相比,MRI检测ACC更加准确。非典型泪滴征是ACC少见且特殊的MRI征象。     

Patient with an Xp21 contiguous gene deletion syndrome in association with agenesis of the corpus callosum

The so-called Xp21 contiguous deletion syndrome or complex glycerol kinase deficiency (GKD) usually presents with classical Duchenne muscular dystrophy (DMD) or a milder dystrophic myopathy, adrenal hypoplasia, and GKD. A number of syndromic and nonsyndromic cases of agenesis of the corpus callosum (ACC) also map to that location. To date, none of the cases of complex GKD have been associated with ACC. Here, we report on a patient with a complex phenotype as a result of the Xp21 contiguous deletion syndrome in association with ACC. Biochemical, cytogenetic, and molecular analyses were performed to detect and establish the size of the genomic deletion. It is at least 3 million base pairs in length; however, exact limits could not be determined in the present study. Nevertheless, we suggest the presence of a primary gene involved in the embryogenesis of the corpus callosum between Xp21.1 and Xp22.11. Am. J. Med. Genet. 70:216–221, 1997. © 1997 Wiley-Liss, Inc.     

Severe pre- and postnatal growth retardation, developmental delay with hypotonia and marked hypotrophy of the distal extremities, dental anomalies, and eczematous skin. A new autosomal recessive entity

We report on three young children, two girls and one boy, with pre- and postnatal growth deficiency, hypotonia, psychomotor retardation with notably impaired speech development, hypotrophy of the distal extremities, small hands and feet, small and widely spaced teeth, eczematous skin, and, in two of them, a partial agenesis of the corpus callosum. To our knowledge this specific combination of features has not been reported before. Since the two girls are sisters and the boy is the product of a consanguineous marriage, the inheritance of this new syndrome appears to be autosomal recessive.     

A homozygous deleterious CDK10 mutation in a patient with agenesis of corpus callosum,retinopathy, and deafness

The primary cilium is a key organelle in numerous physiological and developmental processes. Genetic defects in the formation of this non‐motile structure, in its maintenance and function, underlie a wide array of ciliopathies in human, including craniofacial, brain and heart malformations, and retinal and hearing defects. We used exome sequencing to study the molecular basis of disease in an 11‐year‐old female patient who suffered from growth retardation, global developmental delay with absent speech acquisition, agenesis of corpus callosum and paucity of white matter, sensorineural deafness, retinitis pigmentosa, vertebral anomalies, patent ductus arteriosus, and facial dysmorphism reminiscent of STAR syndrome, a suspected ciliopathy. A homozygous variant, c.870_871del, was identified in the CDK10 gene, predicted to cause a frameshift, p.Trp291Alafs*18, in the cyclin‐dependent kinase 10 protein. CDK10 mRNAs were detected in patient cells and do not seem to undergo non‐sense mediated decay. CDK10 is the binding partner of Cyclin M (CycM) and CDK10/CycM protein kinase regulates ciliogenesis and primary cilium elongation. Notably, CycM gene is mutated in patients with STAR syndrome. Following incubation, the patient cells appeared less elongated and more densely populated than the control cells suggesting that the CDK10 mutation affects the cytoskeleton. Upon starvation and staining with acetylated‐tubulin, γ‐tubulin, and Arl13b, the patient cells exhibited fewer and shorter cilia than control cells. These findings underscore the importance of CDK10 for the regulation of ciliogenesis. CDK10 defect is likely associated with a new form of ciliopathy phenotype; additional patients may further validate this association.     

Craniotubular dysplasia with severe postnatal growth retardation,mental retardation,ectodermal dysplasia,and loose skin: Lenz-Majewski-Like syndrome

The heterogeneous group of craniotubular dysplasias is characterized by modeling errors of the craniofacial and tubular bones. Some conditions in this category cause not only skeletal abnormalities but also a variety of mesoectodermal dysplasias, as exemplified in Lenz-Majewski syndrome (MIM 151050), which comprises craniodiaphyseal dysplasia, failure to thrive, mental retardation, proximal symphalangism, enamel hypoplasia, and loose skin. We report on a boy with a hitherto unknown multisystem disorder, including skeletal changes that were regarded as a form of craniotubular dysplasia. The patient had a large head, exophthalmos, a broad nasal root, anteverted nostrils, large auricles, thick lips, micrognathia, severe postnatal growth retardation with emaciation, severe mental retardation, sparse hair growth, enamel hypoplasia, and thin, loose skin with hyperlaxity. Skeletal changes consisted of thickened calvaria, sclerosis of the skull base and facial bones, thick ribs, and metaphyseal undermodeling of the tubular bones. In addition, generalized osteopenia was evident. The present disorder overlaps phenotypically with Lenz-Majewski syndrome; nevertheless, the absence of diaphyseal hyperostosis and proximal symphalangism in the present patient was not consistent with Lenz-Majewski syndrome. Am. J. Med. Genet. 71:87–92, 1997. © 1997 Wiley-Liss, Inc.     

Hallux duplication,postaxial polydactyly,absence of the corpus callosum,severe mental retardation,and additional anomalies in two unrelated patients: A new syndrome

Two unrelated patients, a 4-year-old boy and a 2 1/2-year-old girl, presented with a similar pattern of abnormalities. Both had severe mental retardation, macrocephaly, absence of the corpus callosum, unusual facial appearance, duplication of hallucal phalanges, postaxial hexadactyly of finger phalanges, and 2/3-syndactyly of toes. The boy also had postaxial hexadactyly of toe phalanges, inguinal hernias and umbilical hernia, and growth retardation. We suspect a common cause of this apparently “new” syndrome, most likely a gene mutation.