COACH syndrome: report of two brothers with congenital hepatic fibrosis, cerebellar vermis hypoplasia, oligophrenia, ataxia, and mental retardation

Case report: Rare genetic liver disease - a case of congenital hepatic fibrosis in adults with autosomal dominant polycystic kidney disease

Congenital hepatic fibrosis (CHF) is considered to be a rare autosomal recessive hereditary fibrocystic liver disease, mainly found in children. However, cases of adult CHF with autosomal dominant polycystic kidney disease (ADPKD) caused by PKD1 gene mutation are extremely rare. We report a 31-year-old female patient admitted for esophageal and gastric variceal bleeding. Physical examination revealed significant splenomegaly, biochemical tests showed a slight increase in liver enzymes, and a decrease in platelet count. Imaging examinations showed significant dilatation of the common bile duct and intrahepatic bile ducts, as well as multiple renal cysts. Liver biopsy revealed enlarged portal areas, bridging fibrosis, and numerous variably shaped small bile ducts. Genetic testing identified two unique mutations in the PKD1 gene, identified as biallelic mutations compound heterozygous mutations composed of a mutation inherited from the father (c.8296 T > C) and one from the mother (c.9653G > C). Based on multiple test results, the patient was diagnosed with the portal hypertension type CHF associated with ADPKD. During her initial hospital stay, the patient underwent endoscopic treatment for gastrointestinal bleeding. To date, the patient has recovered well. Moreover, a significant reduction in varices was observed in a gastroscopy examination 18 months later.

The role of liver transplantation in COACH syndrome (Joubert syndrome with congenital hepatic fibrosis): A review of the literature

BACKGROUND

COACH syndrome is a rare autosomal recessive genetic disease characterized by liver fibrosis, which leads to severe complications related to portal hypertension. However, only a few patients with COACH syndrome undergoing liver transplantation (LT) have been reported.

MATERIALS AND METHODS

We herein report the outcomes of four children who underwent LT for COACH syndrome at our institute and review three previously reported cases to elucidate the role of LT in COACH syndrome.

RESULTS

All four patients in our institute were female, and three received living donors LT. All patients were diagnosed with COACH syndrome by genetic testing. LT was performed in these patients at 3, 7, 9, and 14 years old. The indication for LT was varices related to portal hypertension in all patients. One showed an intrapulmonary shunt. Blood tests revealed renal impairment due to nephronophthisis in three patients, and one developed renal insufficiency after LT. The liver function was maintained in all patients. A literature review revealed detailed information for three more patients. The indication for LT in these three cases was portal hypertension, such as bleeding from esophageal varices. One patient had chronic renal failure on hemodialysis at LT and underwent combined liver and kidney transplantation. Of these three previous patients, one died from hepatic failure due to de novo HCV infection 3 years after LT.

CONCLUSIONS

LT should be considered an effective treatment for COACH syndrome in patients with severe portal hypertension. However, a detailed follow-up of the renal function is necessary.

Access to transplantation for persons with intellectual disability: Strategies for nondiscrimination

Disqualifying patients with intellectual disabilities (ID) from transplantation has received growing attention from the media, state legislatures, the Office of Civil Rights, and recently the National Council on Disability, as well as internationally. Compared with evidence-based criteria used to determine transplant eligibility, the ID criterion remains controversial because of its potential to be discriminatory, subjective, and because its relationship to outcomes is uncertain. Use of ID in determining transplant candidacy may stem partly from perceived worse adherence and outcomes for patients with ID, fear of penalties to transplant centers for poor outcomes, and stigma surrounding the quality of life for people with ID. However, using ID as a contraindication to solid organ transplantation is not evidence-based and reduces equitable access to transplantation, disadvantaging an already vulnerable population. Variability and lack of transparency in referral and evaluation allows for gatekeeping, threatens patient autonomy, limits access to lifesaving treatment, and may be seen as unfair. We examine the benefits and harms of using ID as a transplant eligibility criterion, review current clinical evidence and ethical considerations, and make recommendations for transplant teams and regulatory agencies to ensure fair access to transplant for individuals with ID.

Genetics of syndromic ocular coloboma: CHARGE and COACH syndromes

Optic fissure closure defects result in uveal coloboma, a potentially blinding condition affecting between 0.5 and 2.6 per 10,000 births that may cause up to 10% of childhood blindness. Uveal coloboma is on a phenotypic continuum with microphthalmia (small eye) and anophthalmia (primordial/no ocular tissue), the so-called MAC spectrum. This review gives a brief overview of the developmental biology behind coloboma and its clinical presentation/spectrum. Special attention will be given to two prominent, syndromic forms of coloboma, namely, CHARGE (Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, and Ear anomalies/deafness) and COACH (Cerebellar vermis hypoplasia, Oligophrenia, Ataxia, Coloboma, and Hepatic fibrosis) syndromes. Approaches employed to identify genes involved in optic fissure closure in animal models and recent advances in live imaging of zebrafish eye development are also discussed.

Goldston syndrome with congenital hepatic fibrosis: A rare cause of neonatal cholestasis

Goldston syndrome (GS) is a rare association of Dandy-Walker malformation (DWM) and cystic renal dysplasia with or without hepatic fibrosis. It is considered to be a milder variant of Meckel Gruber syndrome (MGS) and shares features with Miranda syndrome. We reported a 22 day old infant with DWM and autosomal recessive polycystic kidney disease (ARPKD) who presented with cholestasis and acholic stools. Ultrasonography and magnetic resonance cholangiopancreatography (MRCP) confirmed the diagnosis of congenital hepatic fibrosis (CHF). The child improved with supportive treatment. CHF is a rare condition which may present as a syndromic association.

Characteristics of Liver Disease in 100 Individuals With Joubert Syndrome Prospectively Evaluated at a Single Center

BACKGROUND AND AIMS

Joubert Syndrome (JS) is a rare, inherited, ciliopathy defined by cerebellar and brainstem malformations and is variably associated with liver, kidney, and ocular dysfunction. This study characterizes the hepatic findings in JS and identifies factors associated with probable portal hypertension.

METHODS

Hundred individuals with JS were prospectively evaluated at the National Institutes of Health Clinical Center. Laboratory tests, imaging, and DNA sequencing were performed. Patients were stratified based on the spleen length/patient height ratio as a marker of splenomegaly, used as a surrogate for probable portal hypertension.

RESULTS

Forty-three patients (43%) had liver involvement based on elevated liver enzymes and/or liver hyperechogenicity and/or splenomegaly. None of the patients had macroscopic liver cysts or bile duct dilatation. Based on the spleen length/patient height ratio, 13 patients were stratified into a probable portal hypertension group. We observed significant elevations in alkaline phosphatase (269 vs 169 U/L, P ≤ 0.001), alanine aminotransferase (92 vs 42 U/L, P = 0.004), aspartate aminotransferase (77 vs 40 U/L, P = 0.002), and gamma-glutamyl transferase (226 vs 51 U/L, P ≤ 0.001) in the probable portal hypertension group. Platelets were lower in the probable portal hypertension cohort (229 vs 299 × 10 cells/μL, P = 0.008), whereas synthetic function was intact in both groups. Probable portal hypertension was also more prevalent in patients with kidney disease (P = 0.001) and colobomas (P = 0.02), as well as mutations in the TMEM67 gene (P = 0.001).

CONCLUSIONS

In JS, probable portal hypertension is associated with abnormal hepatic enzymes, as well as presence of kidney disease, coloboma, and/or mutation in TMEM67. These findings may allow early identification of JS patients who have or are more likely to develop liver disease.

Consideration of children with intellectual disability as candidates for solid organ transplantation-A practice in evolution

Children with intellectual disability were historically excluded from consideration as recipients of solid organ transplants. In light of an evolution in provider practices, this commentary will define intellectual disability and review the relevant provider attitudes and guidelines and known outcomes of solid organ transplant in this population.

Targeted exome sequencing resolves allelic and the genetic heterogeneity in the genetic diagnosis of nephronophthisis-related ciliopathy

Nephronophthisis-related ciliopathy (NPHP-RC) is a common genetic cause of end-stage renal failure during childhood and adolescence and exhibits an autosomal recessive pattern of inheritance. Genetic diagnosis is quite limited owing to genetic heterogeneity in NPHP-RC. We designed a novel approach involving the step-wise screening of Sanger sequencing and targeted exome sequencing for the genetic diagnosis of 55 patients with NPHP-RC. First, five NPHP-RC genes were analyzed by Sanger sequencing in phenotypically classified patients. Known pathogenic mutations were identified in 12 patients (21.8%); homozygous deletions of NPHP1 in 4 juvenile nephronophthisis patients, IQCB1/NPHP5 mutations in 3 Senior–Løken syndrome patients, a CEP290/NPHP6 mutation in 1 Joubert syndrome patient, and TMEM67/MKS3 mutations in 4 Joubert syndrome patients with liver involvement. In the remaining undiagnosed patients, we applied targeted exome sequencing of 34 ciliopathy-related genes to detect known pathogenic mutations in 7 (16.3%) of 43 patients. Another 18 likely damaging heterozygous variants were identified in 13 NPHP-RC genes in 18 patients. In this study, we report a variety of pathogenic and candidate mutations identified in 55 patients with NPHP-RC in Korea using a step-wise application of two genetic tests. These results support the clinical utility of targeted exome sequencing to resolve the issue of allelic and genetic heterogeneity in NPHP-RC.

Prevalence and Outcomes of Liver Transplantation in Children With Intellectual Disability

OBJECTIVE

We sought to describe the prevalence and outcomes of liver transplantation in children with intellectual disability (ID). We hypothesized that recipients with ID have comparable short-term outcomes compared with those without ID.

METHODS

We performed a retrospective cohort analysis of children receiving a first liver-alone transplant in the United Network for Organ Sharing dataset from 2008 to 2013. Recipients with definite or probable ID were compared to children without ID using χ tests. Kaplan-Meier curves were constructed for patient and graft survival. Cox proportional hazard models were used to estimate the association between ID and graft failure and patient survival.

RESULTS

During the study period, 254 children with definite (115) or probable (139) ID underwent first liver transplant, accounting for 15% of all first pediatric liver transplants (1721). Recipients with definite ID tended to be male have a metabolic indication for transplant, a lower pediatric end-stage liver disease score at listing than recipients with no ID, and were less likely to receive a living donor transplant. Recipients with ID were more likely to have public insurance and had more treatment-related hospitalizations in the first year than those without ID. Functional status tended to improve in all recipients at follow-up. ID was not significantly associated with patient or graft survival.

CONCLUSIONS

Children with ID form a significant portion of total liver transplant recipients, and their short-term graft and patient survival are comparable with children without ID. Further research is needed to examine long-term outcomes of transplant in this population.

Liver involvement in children with ciliopathies

Abnormalities in primary cilia lead to diseases called ciliopathies. Multiple organ involvement is the norm since primary cilia are present in most cells. When cholangiocyte cilia are abnormal, ductal plate malformation ensues leading to such conditions as congenital hepatic fibrosis, Caroli disease or syndrome, or other fibrocystic disease.

Dealing with congenital hepatic fibrosis? Remember COACH syndrome

Coach Syndrome is a rare cause of Congenital Hepatic Fibrosis associated with neurological features. COACH is a mnemonic comprising of Cerebellar vermis hypo/aplasia, Oligophrenia (developmental delay/mental retardation), Ataxia, Coloboma and Hepatic fibrosis. Here we describe a 12 years boy who presented with hepatic encephalopathy. He was subsequently found to have marked developmental delay, bilateral ptosis and ataxia. CT scan revealed brain stem molar tooth sign, ophthalmoscopy showed optic disc coloboma and elastography showed hepatic fibrosis to confirm him as a case of COACH Syndrome.

Joubert syndrome: congenital cerebellar ataxia with the molar tooth

Joubert syndrome is a congenital cerebellar ataxia with autosomal recessive or X-linked inheritance, the diagnostic hallmark of which is a unique cerebellar and brainstem malformation recognisable on brain imaging-the so-called molar tooth sign. Neurological signs are present from the neonatal period and include hypotonia progressing to ataxia, global developmental delay, ocular motor apraxia, and breathing dysregulation. These signs are variably associated with multiorgan involvement, mainly of the retina, kidneys, skeleton, and liver. 21 causative genes have been identified so far, all of which encode for proteins of the primary cilium or its apparatus. The primary cilium is a subcellular organelle that has key roles in development and in many cellular functions, making Joubert syndrome part of the expanding family of ciliopathies. Notable clinical and genetic overlap exists between distinct ciliopathies, which can co-occur even within families. Such variability is probably explained by an oligogenic model of inheritance, in which the interplay of mutations, rare variants, and polymorphisms at distinct loci modulate the expressivity of the ciliary phenotype.

Fatty liver disease and hypertransaminasemia hiding the association of clinically silent Duchenne muscular dystrophy and hereditary fructose intolerance

We report a case with the association of well self-compensated hereditary fructose intolerance and still poorly symptomatic Duchenne type muscular dystrophy. This case illustrates the problems of a correct diagnosis in sub-clinical patients presenting with “cryptogenic” hypertransaminasemia.

Clinical and molecular features of Joubert syndrome and related disorders

Joubert syndrome (JBTS; OMIM 213300) is a rare, autosomal recessive disorder characterized by a specific congenital malformation of the hindbrain and a broad spectrum of other phenotypic findings that is now known to be caused by defects in the structure and/or function of the primary cilium. The complex hindbrain malformation that is characteristic of JBTS can be identified on axial magnetic resonance imaging and is known as the molar tooth sign (MTS); other diagnostic criteria include intellectual disability, hypotonia, and often, abnormal respiratory pattern and/or abnormal eye movements. In addition, a broad spectrum of other anomalies characterize Joubert syndrome and related disorders (JSRD), and may include retinal dystrophy, ocular coloboma, oral frenulae and tongue tumors, polydactyly, cystic renal disease (including cystic dysplasia or juvenile nephronophthisis), and congenital hepatic fibrosis. The clinical course can be variable, but most children with this condition survive infancy to reach adulthood. At least eight genes cause JSRD, with some genotype-phenotype correlations emerging, including the association between mutations in the MKS3 gene and hepatic fibrosis characteristic of the JSRD subtype known as COACH syndrome. Several of the causative genes for JSRD are implicated in other ciliary disorders, such as juvenile nephronophthisis and Meckel syndrome, illustrating the close association between these conditions and their overlapping clinical features that reflect a shared etiology involving the primary cilium.

Mutations in 3 genes (MKS3, CC2D2A and RPGRIP1L) cause COACH syndrome (Joubert syndrome with congenital hepatic fibrosis)

OBJECTIVE

To identify genetic causes of COACH syndrome

BACKGROUND

COACH syndrome is a rare autosomal recessive disorder characterised by Cerebellar vermis hypoplasia, Oligophrenia (developmental delay/mental retardation), Ataxia, Coloboma, and Hepatic fibrosis. The vermis hypoplasia falls in a spectrum of mid-hindbrain malformation called the molar tooth sign (MTS), making COACH a Joubert syndrome related disorder (JSRD).

METHODS

In a cohort of 251 families with JSRD, 26 subjects in 23 families met criteria for COACH syndrome, defined as JSRD plus clinically apparent liver disease. Diagnostic criteria for JSRD were clinical findings (intellectual impairment, hypotonia, ataxia) plus supportive brain imaging findings (MTS or cerebellar vermis hypoplasia). MKS3/TMEM67 was sequenced in all subjects for whom DNA was available. In COACH subjects without MKS3 mutations, CC2D2A, RPGRIP1L and CEP290 were also sequenced.

RESULTS

19/23 families (83%) with COACH syndrome carried MKS3 mutations, compared to 2/209 (1%) with JSRD but no liver disease. Two other families with COACH carried CC2D2A mutations, one family carried RPGRIP1L mutations, and one lacked mutations in MKS3, CC2D2A, RPGRIP1L and CEP290. Liver biopsies from three subjects, each with mutations in one of the three genes, revealed changes within the congenital hepatic fibrosis/ductal plate malformation spectrum. In JSRD with and without liver disease, MKS3 mutations account for 21/232 families (9%).

CONCLUSIONS

Mutations in MKS3 are responsible for the majority of COACH syndrome, with minor contributions from CC2D2A and RPGRIP1L; therefore, MKS3 should be the first gene tested in patients with JSRD plus liver disease and/or coloboma, followed by CC2D2A and RPGRIP1L.

MKS3/TMEM67 mutations are a major cause of COACH Syndrome, a Joubert Syndrome related disorder with liver involvement

The acronym COACH defines an autosomal recessive condition of Cerebellar vermis hypo/aplasia, Oligophrenia, congenital Ataxia, Coloboma and Hepatic fibrosis. Patients present the "molar tooth sign", a midbrain-hindbrain malformation pathognomonic for Joubert Syndrome (JS) and Related Disorders (JSRDs). The main feature of COACH is congenital hepatic fibrosis (CHF), resulting from malformation of the embryonic ductal plate. CHF is invariably found also in Meckel syndrome (MS), a lethal ciliopathy already found to be allelic with JSRDs at the CEP290 and RPGRIP1L genes. Recently, mutations in the MKS3 gene (approved symbol TMEM67), causative of about 7% MS cases, have been detected in few Meckel-like and pure JS patients. Analysis of MKS3 in 14 COACH families identified mutations in 8 (57%). Features such as colobomas and nephronophthisis were found only in a subset of mutated cases. These data confirm COACH as a distinct JSRD subgroup with core features of JS plus CHF, which major gene is MKS3, and further strengthen gene-phenotype correlates in JSRDs.

The first Japanese case of COACH syndrome

COACH syndrome is a disorder characterized by hypoplasia of cerebellar vermis, oligophrenia, congenital ataxia, coloboma and hepatic fibrosis, and 21 cases have been reported to date. Here we describe the first Japanese case of COACH syndrome, who was diagnosed at the age of 37 years and never progressed to liver failure. The patient was found to have delayed developmental milestones at the age of 5 months and mental retardation at the age of 7 years. She had been treated for hepatopathy of unknown origin from the age of 22 years. She was admitted to Hiroshima University Hospital at the age of 37 years after the identification of esophageal varices on a routine upper endoscopy. Computed tomography of the abdomen revealed portal hypertension and splenomegaly, and liver biopsy showed liver fibrosis. In addition, she had coordination disorder and dysarthria. Brain magnetic resonance images revealed hypoplasia of cerebellar vermis. The final diagnosis was COACH syndrome. She underwent endoscopic injection sclerotherapy for esophageal varices. From that point until her death from ovarian cancer at the age of 41 years, the liver function tests were stable without an episode of hematemesis. Physicians should be aware of COACH syndrome when they examine young patients who present with hepatopathy, portal hypertension of unknown origin and cerebellar ataxia.

Joubert syndrome (and related disorders) (OMIM 213300)

Joubert syndrome (JS) and related disorders are characterized by the 'molar tooth sign' (cerebellar vermis hypoplasia and brainstem anomalies) on MRI, hypotonia, developmental delay, ataxia, irregular breathing pattern and abnormal eye movements. Combinations of additional features such as polydactyly, ocular coloboma, retinal dystrophy, renal disease, hepatic fibrosis, encephalocele, and other brain malformations define clinical sub-types. Recent identification of the NPHP1, AHI1, and CEP290 genes has started to reveal the molecular basis of JS, which may implicate the primary cilium in these disorders. Additional genes remain to be identified.

Mental retardation and epilepsy in patients with isolated cerebellar hypoplasia

Congenital nonprogressive cerebellar ataxia includes a complex group of disorders with heterogeneous phenotypic and etiopathogenetic characteristics. Despite recent advances in the understanding of the role of the cerebellum in cognition and behavior, the opinion that the clinical presentation of congenital cerebellar diseases is principally linked to motor dysfunction is common. This is largely due to the lack of well-organized epidemiologic studies on the prevalence of nonmotor disturbances in cerebellar disease. The association between congenital cerebellar disease and epilepsy has rarely been described. We report clinical, neurophysiologic, neuroimaging, and neuropsychologic features in a group of 14 patients with congenital nonprogressive cerebellar ataxia associated with cerebellar hypoplasia, 5 of whom have familial disease, aiming to further a better knowledge of the prevalence of cognitive and/or emotional impairment and epilepsy. The results confirm that cerebellar hypoplasia predisposes individuals to psychomotor delay (71.4%) and cognitive impairment (85.7%). Moreover, the tendency toward abnormal electroencephalographic (EEG) findings (78.5%), associated in a minor percentage of cases with epilepsy (28.5%), is also evident in our study.

Genetic basis of Joubert syndrome and related disorders of cerebellar development

Over three decades have passed since Marie Joubert described the original proband for Joubert syndrome, a rare neurological disorder featuring absence of the cerebellar vermis (i.e. midline). Efforts at deciphering the molecular basis for this disease have been complicated by the clinical and genetic heterogeneity as well as extensive phenotypic overlap with other syndromes. However, progress has been made in recent years with the mapping of three genetic loci and the identification of mutations in two genes, AHI1 and NPHP1. These genes encode proteins with some shared functional domains, but their role in brain development is unclear. Clues may come from studies of related syndromes, including Bardet-Biedl syndrome and nephronophthisis, for which all of the encoded proteins localize to primary cilia. The data suggest a tantalizing connection between intraflagellar transport in cilia and brain development.

Successful combined liver and kidney transplant for COACH syndrome and 5-yr follow-up

The COACH syndrome is a very rare disorder with cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis. Nineteen cases with COACH diagnosis have been reported. Neurologic abnormalities are the first symptoms in most cases. Complications of the hepatopathy [portal hypertension, esophageal varices, and gastrointestinal (GI) bleeding] contribute extensively to the morbidity and lethality in the course of the disease. We describe a 28-yr-old female with COACH syndrome resulting in chronic renal and hepatic insufficiency. The patient was found to have significant mental retardation, truncal ataxia, motor abnormality and occulomotor abnormality. She began to develop GI bleeding and encephalopathy because of biopsy-confirmed cirrhosis. We performed combined liver and kidney transplant after challenging discussion. Her postoperative course was uneventful, and she was discharged on the ninth postoperative day (POD). She has not had any problems at 1, 3 and 5-yr follow-up with excellent liver and renal function. This is the first description of successful combined liver and kidney transplant with long-term follow-up. The decision for transplant is challenging because COACH syndrome is rare with only descriptive characterization and patients have non-progressive ataxia and mental retardation. However, our case shows that liver and kidney transplant can be medically successful, and the individuals achieve long-term success if they have a stable neurological condition and an excellent support system.

Diagnostic approach to cerebellar disease in children

We reviewed the clinical records of 51 extensively investigated pediatric patients with structural abnormalities of the cerebellum as revealed by magnetic resonance imaging (MRI). Ten had hypoplasia of the vermis, 21 had hypoplasia of the vermis and cerebellar hemispheres, 2 had pontocerebellar hypoplasia, and 18 had progressive cerebellar atrophy. A clear diagnosis was reached in 37 (72.5%). Initial characterization of the cerebellar alterations by MRI separated hypoplastic from atrophic cases and confirmed MRI as an essential preliminary means for distinguishing malformations from metabolic-degenerative conditions. However, the diagnostic possibilities are so numerous that it is not feasible to propose a standardized diagnostic protocol for pediatric patients with an altered cerebellum. Subsequent investigations should be suggested by the neuroradiologic and clinical peculiarities of each case.

Molar tooth sign of the midbrain-hindbrain junction: occurrence in multiple distinct syndromes

The Molar Tooth Sign (MTS) is defined by an abnormally deep interpeduncular fossa; elongated, thick, and mal-oriented superior cerebellar peduncles; and absent or hypoplastic cerebellar vermis that together give the appearance of a "molar tooth" on axial brain MRI through the junction of the midbrain and hindbrain (isthmus region). It was first described in Joubert syndrome (JS) where it is present in the vast majority of patients with this diagnosis. We previously showed that the MTS is a component of several other syndromes, including Dekaban-Arima (DAS), Senior-Löken, and COACH (cerebellar vermis hypoplasia (CVH), oligophrenia, ataxia, coloboma, and hepatic fibrosis). Here we present evidence that the MTS is seen together with polymicrogyria, Váradi-Papp syndrome (Orofaciodigital VI (OFD VI)), and a new syndrome with encephalocele and cortical renal cysts. We also present a new patient with COACH syndrome plus the MTS. We propose that the MTS is found in multiple distinct clinical syndromes that may share common developmental mechanisms. Proper classification of patients with these variants of the MTS will be essential for localization and identification of mutant genes.

Congenital ataxia and mental retardation in three brothers

Nonprogressive congenital ataxia is a complex group of disorders caused by a variety of etiologic factors, both environmental and genetic. Hereditary forms represent a substantial part of congenital ataxias, which are difficult to classify because of their phenotypic and genetic polymorphism. Despite the advances in molecular genetics, for most nonprogressive congenital ataxia the etiology is still unknown. This report describes three sons of nonconsanguineous healthy parents, who manifested a syndrome characterized by nonprogressive ataxia, mental retardation, pyramidal signs, ocular and ocular motor anomalies, associated with severe hypoplasia of the cerebellar vermis and hemispheres on neuroimaging. All the patients have presented psychomotor developmental delay. As differential diagnosis, a comparison is made between the clinical features of these patients and the previously reported cases of nonprogressive congenital ataxia. This report represents a further example of the phenotypic and genetic heterogeneity of the syndromes with congenital ataxia.

Biliary tract malformations

The biliary tree extends from the canals of Hering at the margin of the most peripheral portal tracts to the ampulla of Vater. Malformations occur at every level of this structure. Phenotypic features dominate present understanding of these malformations and of the disorders with which they are associated. Classifications of disease will likely shift from a phenotypic basis to a genotypic basis as genes implicated in biliary tree development and function are identified. Involvement of such genes in biliary tree disorders now considered inflammatory, such as extrahepatic biliary atresia, awaits study. The concept of "feeble cholangiocytes" postnatally susceptible to the effects of "toxic bile" is presented.

Linkage analysis in families with Joubert syndrome plus oculo-renal involvement identifies the CORS2 locus on chromosome 11p12-q13.3

Joubert syndrome (JS) is an autosomal recessive developmental brain condition characterized by hypoplasia/dysplasia of the cerebellar vermis and by ataxia, hypotonia, oculomotor apraxia, and neonatal breathing dysregulation. A form of JS that includes retinal dysplasia and cystic dysplastic kidneys has been differentiated from other forms of JS, called either "JS type B" or "cerebello-oculo-renal syndrome" (CORS), but the genetic basis of this condition is unknown. Here, we describe three consanguineous families that display CORS. Linkage analysis defines a novel locus on chromosome 11p12-q13.3, with a maximum two-point LOD score of Z=5.2 at the marker D11S1915. Therefore, the cerebello-oculo-renal form of JS is a distinct genetic entity from the Joubert syndrome 1 (JBTS1) locus described elsewhere, in which there is minimal involvement of retina or kidney. We suggest the term "CORS2" for this new locus.

Human malformations of the midbrain and hindbrain: review and proposed classification scheme

Although a great deal of interest in the genetics and etiology of cerebral, particularly forebrain, malformations has been generated in the past decade, relatively little is known about the basis of congenital malformations of the structures of the posterior fossa, namely the midbrain, cerebellum, pons, and medulla. In this review, we present a classification scheme for malformations of the midbrain and hindbrain based on their embryologic derivation, highlight four of the conditions associated with such abnormalities, and describe the genetics, prognosis, and recurrence risks for each. We describe several disorders in addition to Joubert syndrome with the distinctive radiologic sign known as the "molar tooth sign," comprised of midbrain and hindbrain malformations. We discuss Dandy-Walker malformation, its classical definition, and the surprisingly good outcome in the absence of other brain malformations. We consider the heterogeneous entity of cerebellar vermis hypoplasia and describe the recently identified gene associated with an X-linked form of this condition. Finally, the pontocerebellar hypoplasias are discussed in the context of their generally progressive degenerative and severe course, and the differential diagnosis is emphasized. We anticipate that as imaging technologies improve, differentiation of the various disorders should aid in efforts to identify the causative genes.

Hepatic insufficiency and liver transplantation in a patient with COACH syndrome

An 8-yr-old-patient was diagnosed with COACH syndrome at the moment of her first bleeding episode from esophageal varices. Investigations revealed biliary cirrhosis as the cause of portal hypertension, no visible kidney cyst or impairment of renal function, cerebellar dysplasia with non-disabling ataxia, and minimal mental retardation. By the age of 12 yr she had developed liver insufficiency and, after a challenging discussion, underwent a liver transplantation. She subsequently developed an abdominal aspergillosis, which required several abdominal explorations and splenectomy as well as 6 months of therapy with liposomal amphotericin B, but survived and in long-term follow-up is in good health, with completed puberty, and has finished school.

COACH syndrome associated with multifocal liver tumors

Here, we describe a 20-yr-old woman with COACH syndome (hypoplasia of Cerebellar vermis, Oligophrenia, congenital Ataxia, Coloboma, and Hepatic fibrosis) developing multiple liver lesions. Epigastric and right upper abdominal pain and lack of appetite led to clinical evaluation. Liver function tests showed an increase in transaminases and cholestatic parameters; alpha-fetoprotein was in the normal range. Ultrasound and magnetic resonance imaging examinations revealed multiple liver lesions. Histological examinations of ultrasonographically guided biopsies were consistent with regenerative hepatic nodules without features of malignant or dysplastic cells. The sizes of these tumors did not change over a period of 12 months. Our report presents the 10th case of COACH syndrome with a hitherto undescribed association with hepatic tumors.

Early detection of severe cholestatic hepatopathy in COACH syndrome

COACH syndrome is a disorder with cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis. Sixteen cases with certain COACH diagnosis have been reported so far. Neurologic abnormalities are the first symptoms in most cases. The majority of cases were diagnosed late in childhood or adolescence. Complications of the hepatopathy contribute extensively to the morbidity and lethality in the course of the disease. Major complications are portal hypertension, esophageal varices, and gastrointestinal bleeding. We report of a child with only mild neurologic symptoms, but severe hepatic fibrosis with cholangiopathy, and review the literature. This is the first description of profound cholestatic hepatopathy in a very young child with COACH syndrome. The patient was found to have cerebellar vermis hypoplasia, unilateral optical nerve coloboma, mild dysmorphic signs, and a ventricular septum defect. Routine laboratory investigations eventually revealed elevated liver enzymes. Prothrombin time was abnormal. Ultrasound scan of the liver was normal. Hepatotropic viral infections were excluded. We performed a liver biopsy at the age of 16 months, confirming an early stage of cirrhosis with septal fibrosis and pseudolobules, inflammatory infiltrates, signs of cholestasis, and reduced numbers of intrahepatic bile ducts. Early detection and differentiation of liver pathology are important in COACH syndrome. Progressive destructive cholangiopathy may contribute to hepatic fibrosis in COACH syndrome. Liver disease can be severe even in cases with mild neurologic deficits.

Abnormal supranuclear eye movements in the child: a practical guide to examination and interpretation

Abnormal eye movements in the infant or voting child can be congenital or acquired. They may be a result of abnormal early visual development or a sign of underlying neurologic or neuromuscular disease. It is important to be able to detect these abnormalities and to distinguish them from normal but immature eye movements. The spectrum of disease in children differs from that in adults. Serious, potentially fatal but treatable disorders can be acquired in infancy, and abnormal eye movements in a sometimes apparently well child should never be labeled as congenital or benign without careful investigation. Eye movement analysis can indicate the presence of an underlying condition and help the clinician to classify different neurologic diseases. It is important to carefully examine the ocular motor system in any children at risk of neurologic disease. This review provides a practical guide to the examination and interpretation of eye movements in the child and includes recent literature on eye movement disorders of childhood. We describe supranuclear abnormalities of the ocular motor system in the order in which we would normally examine it: saccades, pursuit, convergence, vestibulo-ocular reflex, and optokinetic nystagmus. Nystagmus, internuclear ophthalmoplegia, cranial nerve abnormalities, and "miswiring" phenomena (such as Duane's syndrome and synergistic divergence) are not discussed.