Cranioectodermal dysplasia: a probable ciliopathy.

Cranioectodermal dysplasia (CED), also known as Sensenbrenner syndrome, is a rare autosomal recessive genetic disorder characterized by typical craniofacial, skeletal and ectodermal defects, and tubulointerstitial nephritis leading to early end-stage renal failure. We report on a new familial case of a 9-year-old patient and two fetuses of 23 and 19 weeks of gestation respectively. Hypohidrosis was an additional ectodermal finding is the patient with CED. Postmortem findings in the two fetuses included acromesomelic shortening, craniofacial characteristics with absence of craniosynostosis, small kidneys with tubular and glomerular microscopic cysts, persistent ductal plate with portal fibrosis in the liver, small adrenals and roughly unremarkable histopathology of the physeal growth plate. Posterior fossa anomalies were additional findings in this patient and included an enlarged cisterna magna and a posterior fossa cyst. The above findings, in association with renal cysts, persistent ductal plate and portal fibrosis, introduce CED, a nonlethal genetic skeletal disorder of yet unknown molecular origin, as a possible member of the expanding group of ciliopathies.

Genetic skeletal disorders of the fetus and infant: pathologic and molecular findings in a series of 41 cases.

BACKGROUND: Genetic skeletal disorders of the fetus and infant are a large group of genetic disorders, comprising the groups formerly assigned as skeletal dysplasias (osteochondrodysplasias), dysostoses, and malformation syndromes with a skeletal component. Genetic skeletal disorders may be prenatally detected by ultrasonography or result in intrauterine or early postnatal death, constituting one difficult diagnostic field met by the pathologist who performs the perinatal autopsy. METHODS: In this retrospective study, we have gathered radiologic, physical, histopathologic, and molecular data regarding 41 cases of genetic skeletal disorders diagnosed among 1980 fetal and perinatal autopsies over a 10-year period. RESULTS: Our series of cases were classified according to the 2006 Nosology and Classification of Genetic Skeletal Disorders. The overall frequency of genetic skeletal disorders was 1:48 autopsies. The FGFR3 group and osteogenesis imperfecta type 2 were the more frequently encountered disorders. The mean gestational age at autopsy was 21.9 weeks (range, 12-37 weeks). A final diagnosis was obtained in 95% of cases. Genetic skeletal disorders were detected by prenatal ultrasound in 90% of cases, with a correct typing of the disorder achieved in only 34%. Molecular analysis was confirmative in 5 cases. CONCLUSIONS: The central role of the perinatal pathologist in collaboration with specialized services is essential for the correct interpretation of the radiologic, physical, and histopathologic findings, to accurately classify specific types of genetic skeletal disorders and enable genetic counseling.

Hepatocerebral form of mitochondrial DNA depletion syndrome: novel MPV17 mutations.

BACKGROUND: Autosomal recessive mutations in MPV17 (OMIM *137960) have been identified in the hepatocerebral form of mitochondrial DNA depletion syndrome (MDS). OBJECTIVE: To describe the clinical, morphologic, and genetic findings in 3 children with MPV17-related MDS from 2 unrelated families. DESIGN: Case report. SETTING: Academic research. MAIN OUTCOME MEASURES: We identified 3 novel pathogenic mutations in 3 children. RESULTS: Two children were homozygous for nonsense mutation p.W120X. A third child was compound heterozygous for missense mutation p.G24W and for a macrodeletion spanning MPV17 exon 8. All patients demonstrated lactic acidosis, hypoglycemia, hepatomegaly, and progressive liver failure. Neurologic symptoms manifested at a later stage of the disease. Death occurred within the first year of life in all 3 patients. CONCLUSIONS: These data confirm that MPV17 mutations are associated with a 2-stage syndrome. The first symptoms are metabolic and rapidly progress to hepatic failure. This stage is followed by neurologic involvement affecting the central and peripheral systems.

Pathologic, radiographic and molecular findings in three fetuses diagnosed with HEM/Greenberg skeletal dysplasia.

BACKGROUND: Greenberg skeletal dysplasia is a very rare, autosomal recessive, in utero, lethal chondrodystrophy for which only eight index cases of diverse ethnic origin have been reported so far. The defect is associated with a defect in cholesterol biosynthesis and due to mutations in the gene encoding the lamin B receptor (LBR). METHODS: A familial case of three fetuses of a consanguineous Greek couple is presented including prenatal, physical, radiographic, histopathologic, and molecular genetic findings. RESULTS: The tentative diagnosis of Greenberg skeletal dysplasia based on pathological findings was confirmed by the identification of a homozygous, N547D amino acid substitution in the LBR gene in the third affected fetus. CONCLUSION: The present case represents the ninth described case of Greenberg dysplasia and the second case of Greek origin. The characteristic 'moth-eaten' radiographic appearance is already seen at 13 weeks' gestational age.

Navajo neurohepatopathy is caused by a mutation in the MPV17 gene.

Navajo neurohepatopathy (NNH) is an autosomal recessive disease that is prevalent among Navajo children in the southwestern United States. The major clinical features are hepatopathy, peripheral neuropathy, corneal anesthesia and scarring, acral mutilation, cerebral leukoencephalopathy, failure to thrive, and recurrent metabolic acidosis with intercurrent infections. Infantile, childhood, and classic forms of NNH have been described. Mitochondrial DNA (mtDNA) depletion was detected in the livers of two patients, suggesting a primary defect in mtDNA maintenance. Homozygosity mapping of two families with NNH suggested linkage to chromosome 2p24. This locus includes the MPV17 gene, which, when mutated, causes a hepatocerebral form of mtDNA depletion. Sequencing of the MPV17 gene in six patients with NNH from five families revealed the homozygous R50Q mutation described elsewhere. Identification of a single missense mutation in patients with NNH confirms that the disease is probably due to a founder effect and extends the phenotypic spectrum associated with MPV17 mutations.

Prenatal diagnosis of glycogen storage disease type IV.

BACKGROUND: Glycogen storage disease type IV (GSD-IV) is a rare autosomal recessive disorder due to mutations in the GBE1 gene causing deficiency of the glycogen branching enzyme (GBE). Prenatal diagnosis has occasionally been performed by the measurement of the GBE activity in cultured chorionic villi (CV) cells. METHODS: Two unrelated probands with severe hypotonia at birth and death during the neonatal period were diagnosed with GSD-IV on the basis of postmortem histological findings. DNA analysis revealed truncating GBE1 mutations in both families. RESULTS: Prenatal diagnosis was performed in subsequent pregnancies by determination of branching enzyme activity and DNA analysis of CV or cultured amniocytes. Detailed autopsies of the affected fetuses at 14 and 24 weeks of gestation demonstrated intracellular inclusions of abnormal glycogen characteristic of GSD-IV. CONCLUSION: Prenatal diagnosis of GSD-IV by DNA analysis is highly accurate in genetically confirmed cases.

Prenatal diagnosis of achondroplasia presenting with multiple-suture synostosis: a novel association.

OBJECTIVE: We report an atypical case of a fetus presenting with a combined achondroplasia and multiple craniosynostosis phenotype. METHODS: Sonographic monitoring in conjunction with molecular genetic analysis was performed in a 32-gestational weeks fetus. RESULTS: Sonographic findings were consistent with a diagnosis of achondroplasia associated with multiple-suture synostosis. The most common G380R FGFR3 achondroplasia mutation was detected. CONCLUSION: The most common achondroplasia mutation should be considered for prenatal DNA testing in cases with ultrasound findings of achondroplasia and multiple-suture synostosis. This is crucial for the genetic counselling and perinatal management of the fetus.

Mitochondrial myopathy and ophthalmoplegia in a sporadic patient with the G12315A mutation in mitochondrial DNA.

A 21-year-old woman described proximal muscle weakness since early childhood. At age 16, she developed bilateral ptosis, progressive external ophthalmoplegia, and exercise intolerance. She harbored a heteroplasmic G12315A mutation in the mitochondrial DNA tRNA(Leu(CUN)) gene, which disrupts a highly conserved G-C base pair in the TPsiC stem of the molecule. Mutant mitochondrial DNA was 62% of total in muscle and 17% in blood. The mutation was undetectable in blood, urinary sediment, and hair follicles from the patient's mother. This second patient with G12315A and progressive external ophthalmoplegia confirms the pathogenicity of the mutation and helps to define the correlation between genotype and phenotype.