Pseudoachondroplasia and multiple epiphyseal dysplasia due to mutations in the cartilage oligomeric matrix protein gene.

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are dominantly inherited chondrodysplasias characterized by short stature and early-onset osteoarthrosis. The disease genes in families with PSACH and MED have been localized to an 800 kilobase interval on the short arm of chromosome 19. Recently the gene for cartilage oligomeric matrix protein (COMP) was localized to chromosome 19p13.1. In three patients with these diseases, we identified COMP mutations in a region of the gene that encodes a Ca++ binding motif. Our data demonstrate that PSACH and some forms of MED are allelic and suggest an essential role for Ca++ binding in COMP structure and function.

Phenotype and genotype in mucolipidoses II and III alpha/beta: a study of 61 probands.

BACKGROUND: Mucolipidoses II and III alpha/beta (ML II and ML III) are lysosomal disorders in which the essential mannose 6-phosphate recognition marker is not synthesised on to lysosomal hydrolases and other glycoproteins. The disorders are caused by mutations in GNPTAB, which encodes two of three subunits of the heterohexameric enzyme, N-acetylglucosamine-1-phosphotransferase. OBJECTIVES: Clinical, biochemical and molecular findings in 61 probands (63 patients) are presented to provide a broad perspective of these mucolipidoses. METHODS: GNPTAB was sequenced in all probands and/or parents. The activity of several lysosomal enzymes was measured in plasma, and GlcNAc-1-phosphotransferase was assayed in leucocytes. Thirty-six patients were studied in detail, allowing extensive clinical data to be abstracted. RESULTS: ML II correlates with near-total absence of phosphotransferase activity resulting from homozygosity or compound heterozygosity for frameshift or nonsense mutations. Craniofacial and orthopaedic manifestations are evident at birth, skeletal findings become more obvious within the first year, and growth is severely impaired. Speech, ambulation and cognitive function are impaired. ML III retains a low level of phosphotransferase activity because of at least one missense or splice site mutation. The phenotype is milder, with minimal delays in milestones, the appearance of facial coarsening by early school age, and slowing of growth after the age of 4 years. CONCLUSIONS: Fifty-one pathogenic changes in GNPTAB are presented, including 42 novel mutations. Ample clinical information improves criteria for delineation of ML II and ML III. Phenotype-genotype correlations suggested in more general terms in earlier reports on smaller groups of patients are specified and extended.

Recessive osteogenesis imperfecta caused by LEPRE1 mutations: clinical documentation and identification of the splice form responsible for prolyl 3-hydroxylation.

BACKGROUND: Recessive forms of osteogenesis imperfecta (OI) may be caused by mutations in LEPRE1, encoding prolyl 3-hydroxylase-1 (P3H1) or in CRTAP, encoding cartilage associated protein. These proteins constitute together with cyclophilin B (CyPB) the prolyl 3-hydroxylation complex that hydroxylates the Pro986 residue in both the type I and type II collagen alpha1-chains. METHODS: We screened LEPRE1, CRTAP and PPIB (encoding CyPB) in a European/Middle Eastern cohort of 20 lethal/severe OI patients without a type I collagen mutation. RESULTS: Four novel homozygous and compound heterozygous mutations were identified in LEPRE1 in four probands. Two probands survived the neonatal period, including one patient who is the eldest reported patient (17 7/12 years) so far with P3H1 deficiency. At birth, clinical and radiologic features were hardly distinguishable from those in patients with autosomal dominant (AD) severe/lethal OI. Follow-up data reveal that the longer lived patients develop a severe osteochondrodysplasia that overlaps with, but has some distinctive features from, AD OI. A new splice site mutation was identified in two of the four probands, affecting only one of three LEPRE1 mRNA splice forms, detected in this study. The affected splice form encodes a 736 amino acid (AA) protein with a "KDEL" endoplasmic reticulum retention signal. While western blotting and immunocytochemical analysis of fibroblast cultures revealed absence of this P3H1 protein, mass spectrometry and SDS-urea-PAGE data showed severe reduction of alpha1(I)Pro986 3-hydroxylation and overmodification of type I (pro)collagen chains in skin fibroblasts of the patients. CONCLUSION: These findings suggest that the 3-hydroxylation function of P3H1 is restricted to the 736AA splice form.

Mutant enzymatic and cytological phenotypes in cultured human fibroblasts.

Fibroblasts were cultured from the cells of two children who shared some characteristics of Hurler syndrome, but they did not show corneal clouding and excessive excretion of mucopolysaccharides. The fibroblasts differ from those of controls and of patients with typical Hurler syndrome or other mucopolysaccharidoses in that they have abundant cytoplasmic inclusions, striking diminutions in beta-glucuronidase, and elevations in acid phosphatase.

Tay-Sachs disease: prenatal diagnosis.

Fifteen pregnant women with a 25 percent risk of delivering a child with Tay-Sachs disease were monitored by amniocentesis and hexosaminidase A assays of amniotic fluid, uncultured amniotic cells, and cultured amniotic cells. Tay-Sachs disease was diagnosed prenatally in six fetuses; the diagnosis was confirmed in one child after birth and in five fetuses after therapeutic abortion. Prenatal diagnosis indicated the absence of Tay-Sachs disease in nine other fetuses; this diagnosis was confirmed postnatally in six, three are still in utero.

Perinatal manifestations of maternal yellow nail syndrome.

A term female firstborn infant had unexplained nonimmune fetal hydrops and recurrent left chylothorax at 4 weeks of age. A few months before conception, her mother had had acute dystrophic nail changes and is being treated for recurrent sinusitis, bronchiectasis, and a deficiency of serum IgG2. We suggest that they both suffer from a dominantly inherited congenital lymphedema syndrome known as 'yellow nail dystrophy.' Prenatal manifestation of this disorder has not been reported previously. The child's anthropometric and neurological development was normal at 1 year of age, whereas mild ankle edema and marbling of the skin of the limbs were salient clinical findings. Inherited lymphedema leading to nonimmune fetal hydrops also has been recognized in chromosomal disorders, Noonan's syndrome, multiple pterygium syndrome, pulmonary lymphangiectasis, and mixed-vessel lymphatic dysfunction. Indicators of parental lymphedema are not on record in those instances.

Fibrotic eye muscles, Axenfeld anomaly, flat face, and mild developmental retardation: a new example of the Chitty syndrome.

We have studied a girl with fibrotic extrinsic eye muscles, Axenfeld anomaly, unusual facial appearance, mild hydrocephaly, and neurodevelopmental delay. Her condition is similar to the one described recently in members of a single family by Chitty et al. [1991, Am J Med Genet 40:417-420]. We suggest that she represents a second example of what may be called the Chitty syndrome.

Blomstrand lethal osteochondrodysplasia.

We present the clinical, roentgenographic, and histologic abnormalities in a stillborn infant with Blomstrand osteochondrodysplasia. Parental consanguinity and multiplex occurrence in the patients' sibship confirm the hypothesis of autosomal recessive inheritance of this monogenic lethal entity. The unknown genetic defect interferes severely with skeletal growth through lack of chondrocyte multiplication and apparent uncoupling of the processes of enchondral ossification and skeletal growth.

Osteoporosis-pseudoglioma syndrome.

Two patients with osteoporosis pseudoglioma syndrome are described. Both are single children, born to nonconsanguineous, healthy parents. The first patient, a 17-year-old girl, had serious visual impairment since birth. She is severely dwarfed and has major skeletal deformities resulting in inability to walk since age 2 years. The second patient is an 18-year-old girl with unilateral neonatal blindness, short stature and deformities, mainly of pelvis and lower limbs. She has been able to walk with support up to now. The clinical and radiological findings in these 2 patients reflect the clinical variability of the condition. Results of collagen studies in both patients are normal and differentiate this condition clearly from severe osteogenesis imperfecta, which it resembles.

The Meier-Gorlin syndrome, or ear-patella-short stature syndrome, in sibs.

The Meier-Gorlin syndrome, first described by Meier and Rothschild [1959: Helv Paediatr Acta 14:213-216] and further delineated by Gorlin et al. [1975: A Selected Miscellany, p 39-50], is characterized by short stature, slender body build, craniofacial anomalies, microtia, delayed skeletal development, hypogonadism, and absence of the patellae. It has also been called the ear-patella-short stature syndrome [Boles et al., 1994: Clin Dysmorphol 3:207-214]. We report on two brothers with Meier-Gorlin syndrome, the younger of whom was more severely affected. Both patients had severe deafness and congenital labyrinthine anomalies, which have not previously been described as features of this syndrome. The neuromotor and mental development of these patients was adversely affected by late diagnosis, deafness, and their sociocultural environment, but their cognitive ability fell within the range observed in other Meier-Gorlin patients. Neuroradiographic imaging and functional inner ear investigations are recommended in the diagnostic workup of this rather specific, probably autosomal recessive mental retardation syndrome with multiple congenital anomalies.

Pallister-Killian syndrome: characterization of the isochromosome 12p by fluorescent in situ hybridization.

The isochromosome 12p (i(12p)) in fibroblasts of 3 patients with Pallister-Killian syndrome and one decreased prematurely born neonate, was characterized by fluorescent in situ hybridization (FISH) using chromosome 12-specific DNA probes. FISH is a useful technique for rapid and reliable detection and characterization of the i(12p) chromosome in Pallister-Killian patients. Detection was possible also in interphase cells. In addition, the in vitro selection against i(12p) cells at different passages in fibroblast cultures of two patients was monitored.

Subtelomeric familial translocation t(2;7)(q37;q35) leading to partial trisomy 7q35-->qter: molecular cytogenetic analysis and clinical phenotype in two generations.

Few patients with trisomy of the most distal region of chromosome 7q have been described. We report on a familial translocation t(2;7)(q37;q35) leading to trisomy 7q35-->7qter in a child and her paternal uncle and a minimal deletion of distal 2q as demonstrated by FISH with probes located in the chromosome 2q subtelomeric region. The clinical phenotype included macrocephaly and low-set ears, also found in other reported patients trisomic for the distal part of chromosome 7q. Phenotypic findings probably useful for the clinical diagnosis include normal size at birth, large head with frontal bossing, low-set ears of normal shape, small nose and low nasal bridge, feeding difficulties in infancy, and severe neurodevelopmental delay.

On the variability of the Brachmann-de Lange syndrome in seven patients.

The results of the clinical and radiographic study of 7 patients support the view of a unimodal and rather narrow phenotypic spectrum in the Brachmann-de Lange syndrome (BDLS) and reject the existence of a "classic" type of patient and a "mild phenotype" without upper limb defects who survive with moderate to severe mental retardation. Similarity among all patients is greater than their phenotypic differences. Strict clinical definition of the syndrome warrants easier access to the still unknown cause, most probably a single gene mutation with autosomal dominant inheritance.

Tricho-rhino-phalangeal syndrome type I (TRP I) due to an apparently balanced translocation involving 8q24.

Tricho-rhino-phalangeal (TRP) syndromes type I and II are caused by a defective gene located on chromosome 8q24.1. We report a family with 2 sibs affected with TRP type I in combination with an apparently balanced chromosome (8;18) translocation involving 8q24.11. It is very likely that the 8q24 translocation breakpoint is physically linked to the TRP gene(s), thereby facilitating future efforts to clone the TRP gene(s).

Malignant melanoma of soft parts. Further cytogenetic characterization.

We report the cytogenetic findings in a case of malignant melanoma of soft parts. Overrepresentation of 1q together with a del(1)(q42), extra copies of chromosomes 7 and 8, and t(12;22)(q13;q13) were found. These findings allow further delineation of the chromosomal pattern found in this uncommon neoplasm.

Cytogenetic analysis of a mesenchymal hamartoma of the liver.

Cytogenetic analysis of a mesenchymal hamartoma of the liver in a 3-year-old child revealed a balanced translocation between chromosomes 15 and 19 as the sole chromosome change.

Acid maltase deficiency (type II glycogenosis). Morphological and biochemical study of a childhood phenotype.

Pathological and biochemical data are reported on a 4(4)/12-year-old male patient with a severe myopathic disorder, hepatomegaly, recurrent pulmonary infections ending fatally. Combined morphological and enzymatic studies on muscle biopsy led to the diagnosis of acid maltase deficiency (Type II glycogenosis). On post mortem examination, lysosomal glycogen storage is found in skeletal muscles and liver, while heart and central nervous sytem are spared. Both hydrolytic and transferase activities of acid maltase are absent in cultured fibroblasts, heart, liver and postmortem skeletal muscles. That in the biopsied skeletal muscle only, the transferase activity alone is deficient while the hydrolytic function is maintained at low normal levels correlates well with the abnormal structure of the glycogen stored in that muscle. However, these findings on biopsied muscle cannot be reconciled with the absence of both functions and the presence of normal glycogen in other biopsied tissues or in postmortem specimens from the same patient.

alpha-D-mannosidases in serum of patients with I-cell disease (ICD).

The specific activity of alpha-D-mannosidase in serum of ICD-patients is considerably increased due to increased amounts of the component with optimal activity at pH 4.6 (acidic form). The intermediate form with pH optimum of 6.0 remains unaltered. These conclusions were reached by using optimal conditions for differential assay of the alpha-D-mannosidases checked by partial separation of the components in serum by sucrose gradient centrifugation.

Arylsulphatases A and B in human diploid fibroblasts: differential assay with 4-methylumbelliferylsulphate and AgNO3.

A new technique is introduced for the differential assay of arylsulphatases A and B in centrifuged homogenates of cultured human skin fibroblasts, using 4-methylumbelliferyl-sulphate as a substrate and AgNO3 as a selective inhibitor of arylsulphatase A. The method can be applied in the diagnosis of metachromatic leucodystrophy, mucopolysaccharidosis type VI and mucosulphatidosis. Normal arylsulphatase activities were found in fibroblasts derived from patients with mucopolysaccharidoses types II, III-A and IV, known to be caused by deficiencies of various other sulphatases.

MRI findings in a neonate with cerebellar agenesis.

Cerebellar agenesis is a rarely observed malformation that is frequently associated with other defects. We describe a neonate with an isolated cerebellar agenesis. In addition to the absence of recognizable cerebellar tissue, cranial magnetic resonance imaging demonstrated a hypoplastic base of the pons and absence of the normal outline of the inferior olives. Other major cerebral malformations were not found. As a developmental defect, cerebellar agenesis is heterogeneous because it occurs either as an anatomically isolated anomaly or as part of a more complex cerebral malformation. The pathogenesis and molecular basis of isolated cerebellar agenesis is unknown.