Mutation in transcription factor POU4F3 associated with inherited progressive hearing loss in humans.

The molecular basis for autosomal dominant progressive nonsyndromic hearing loss in an Israeli Jewish family, Family H, has been determined. Linkage analysis placed this deafness locus, DFNA15, on chromosome 5q31. The human homolog of mouse Pou4f3, a member of the POU-domain family of transcription factors whose targeted inactivation causes profound deafness in mice, was physically mapped to the 25-centimorgan DFNA15-linked region. An 8-base pair deletion in the POU homeodomain of human POU4F3 was identified in Family H. A truncated protein presumably impairs high-affinity binding of this transcription factor in a dominant negative fashion, leading to progressive hearing loss.

A single ataxia telangiectasia gene with a product similar to PI-3 kinase.

A gene, ATM, that is mutated in the autosomal recessive disorder ataxia telangiectasia (AT) was identified by positional cloning on chromosome 11q22-23. AT is characterized by cerebellar degeneration, immunodeficiency, chromosomal instability, cancer predisposition, radiation sensitivity, and cell cycle abnormalities. The disease is genetically heterogeneous, with four complementation groups that have been suspected to represent different genes. ATM, which has a transcript of 12 kilobases, was found to be mutated in AT patients from all complementation groups, indicating that it is probably the sole gene responsible for this disorder. A partial ATM complementary DNA clone of 5.9 kilobases encoded a putative protein that is similar to several yeast and mammalian phosphatidylinositol-3' kinases that are involved in mitogenic signal transduction, meiotic recombination, and cell cycle control. The discovery of ATM should enhance understanding of AT and related syndromes and may allow the identification of AT heterozygotes, who are at increased risk of cancer.

A new locus for autosomal dominant posterior polar cataract in Moroccan Jews maps to chromosome 14q22-23.

BACKGROUND: Posterior polar cataract is a clinically distinctive opacity located at the back of the lens. It is commonly acquired in age related cataract, and may infrequently occur in pedigrees with congenital cataract. To date, five loci for autosomal dominant congenital posterior polar cataract have been identified. These include two genes, CRYAB and PITX3, on chromosomes 11q and 10q respectively, and three loci with as yet unknown genes on chromosomes 1p, 16q and 20p. PURPOSE: To find the chromosomal location of a gene causing autosomal dominant congenital posterior polar cataract in three Moroccan Jewish families. METHODS: A whole genome scan was performed using microsatellite markers spaced at approximately 10 cM intervals. For fine mapping, five additional microsatellite markers were genotyped. Two-point lod scores were calculated using MLINK software, from the LINKAGE program package. After linkage was established, several positional candidate genes were assessed by PCR based DNA sequencing. RESULTS: The new cataract locus was mapped to an 11.3 cM interval between D14S980 and D14S1069 on chromosome 14q22-23. A maximum two point lod score of 5.19 at theta = 0 was obtained with the markersD14S274. The positional and functional candidate genes SIX1, SIX4, SIX6, OTX2, and ARHJ were excluded as the cause of cataract in these families. CONCLUSION: An as yet unidentified gene associated with posterior polar cataract maps to the long arm of chromosome 14q22-23.

Lower frequency of Gaucher disease carriers among Tay-Sachs disease carriers.

The heterozygote frequency of Gaucher disease (GD) and Tay-Sachs disease (TSD) is distinctly high among Ashkenazi Jews (1:29 for TSD and 1:16 for GD). Two main theories have been suggested to explain this high occurrence: a founder effect with subsequent genetic drift, and a selective advantage of heterozygotes. We compared the frequency of the GD most common mutation (1226A-->G) among carriers of the common TSD mutation (+1277 TATC) with the frequency of this mutation in the general Ashkenazi population. The frequency of GD carriers among 308 TSD heterozygotes was 1:28 which is about half the expected (P = 0.03). These results indicate that carriers of both diseases do not possess additional evolutionary advantage over single mutation carriers. A reasonable interpretation of these findings is that one or both mutations have arisen relatively recently in different regions of Europe and have not yet reached genetic equilibrium.

Predictive testing for Wilson's disease using tightly linked and flanking DNA markers.

We studied DNA polymorphisms for five new chromosome 13 markers in 52 Wilson's disease (WD) families from Europe, North America, and the Middle East. There was significant evidence for linkage between the Wilson's disease locus (WND) and all the marker loci. Multilocus linkage analysis, using a genetic linkage map established from reference pedigrees, suggested that WND is most likely between D13S31 and D13S59, at distances of 0.4 and 1.2 centimorgans, respectively. Our results suggest that the chromosomal location of the Wilson's disease gene is the same in all families from the populations studied. This evidence and the availability of many close, flanking, and polymorphic DNA markers make possible accurate and informative testing of potential carriers and WD homozygotes in families with at least one previously affected child. An advantage of a genetic linkage test over other laboratory methods for prediction of genotype in WD is that a reliable diagnosis can be made at a much earlier stage in life, including prenatally. In addition, DNA testing can be used in place of an invasive liver biopsy procedure to confirm a diagnosis in patients with borderline serum ceruloplasmin levels. Presymptomatic identification will also allow therapeutic intervention to prevent symptoms before irreparable liver or neurologic damage occurs. We describe the implementation of prenatal and preclinical diagnosis for two families with WD.

A nonsense mutation (W9X) in CRYAA causes autosomal recessive cataract in an inbred Jewish Persian family.

PURPOSE: To identify the genetic defect causing autosomal recessive cataract in two inbred families. METHODS: Linkage analysis was performed with polymorphic markers close to 14 loci previously shown to be involved in autosomal dominant congenital cataract. In one of the families a gene segregating with the disease was analyzed by single-strand conformation polymorphism (SSCP) and eventually sequenced. RESULTS: Three polymorphic markers close to the CRYAA gene located on chromosome 21q segregated with the disease phenotype in one of the families, but not in the other. Sequencing of the CRYAA in this Jewish Persian family revealed a G-to-A substitution, resulting in the formation of a premature stop codon (W9X). CONCLUSIONS: A nonsense mutation in the CRYAA gene causes autosomal recessive cataract in one family. This constitutes the first description of the molecular defect underlying nonsyndromic autosomal recessive congenital cataract. That there was no linkage to this locus in another family provides evidence for genetic heterogeneity.

Antithrombin III and heparin cofactor II in patients with chronic renal failure undergoing regular hemodialysis.

Heparin enhances the inhibition rate of thrombin by both antithrombin III (AT III) and heparin cofactor II (HC II). We studied the activity of these two plasma proteins in patients with chronic renal failure (CRF) undergoing regular hemodialysis as their heparin requirements varied widely. In 77 normal blood donors, normal ranges (mean +/- 2 SD) were 82-122% for AT III and 65-145% for HC II. When compared with these controls 82 dialyzed CRF patients had a subnormal AT III activity and a significantly (p less than 0.001) lower HC II activity. To evaluate the effect of hemodialysis we compared AT III, HC II and total proteins in plasma before and after dialysis in 24 patients (12 with normal and 12 with low basal HC II activity). AT III and HC II activities significantly (p less than 0.001) increased in absolute value. When related to total plasma proteins, in order to suppress the influence of hemoconcentration induced by dialysis, AT III decreased significantly (p less than 0.01) whereas HC II increased slightly but significantly (p less than 0.01) in the 12 patients with low initial HC II activity. The decrease of AT III induced by heparin administrated during dialysis is likely to account for this relative decrease of AT III activity. A modification of the distribution of both HC II and heparin between the vascular wall and the circulating blood is evoked to explain the relative increase in HC II activity and the need for higher heparin dosage in patients with low HC II levels.

Leukonychia totalis in two sibs.

A sister and a brother, offspring of unaffected consanguineous Arab parents, were found to have leukonychia totalis and flat, wide nails. To our knowledge this is the first report of apparent autosomal recessive transmission of this trait. A parental somatic mutation with gonadal mosaicism may explain the unusual segregation of the trait in this family.

Ambiguous genitalia in the Proteus syndrome.

An 11-year-old girl was followed up since birth because of hemihypertrophy of the left leg and thigh, multiple pigmented nevi and subcutaneous tumors typical of the Proteus syndrome. Because of clitoromegaly and scrotal-like hypertrophy of the labia majora, she had an endocrine evaluation the results of which were normal. The findings are thought to represent local genital hypertrophy. Ambiguous genitalia have to be added to the phenotype of the Proteus syndrome.

Trigonocephaly: a new familial syndrome.

Trigonocephaly was found in six relatives through three generations of one family. The propositus was ascertained at birth because of omphalocele. In addition to trigonocephaly, he had minor ear, vertebral, and genital abnormalities. His father had mild microcephaly, and both had minor eye abnormalities. None of the other four affected individuals had any other malformations. In this family, trigonocephaly is an autosomal dominant trait. The ratio of affected males to affected females was 5 to 1, and although the paucity of affected females is not statistically significant, we speculate that it may reflect variable expressivity or sex limitation of the trait. We conclude that the condition in this family represents a unique syndrome in which trigonocephaly is not associated with functional brain abnormalities and where craniosynostosis is limited to the metopic region.

Interstitial 7q deletion [46,XY,del (7) (pter----cen::q112----qter)] in a retarded quadriplegic boy with normal beta glucuronidase.

A 14-year-old severely retarded male with deletion of chromosomal band 7 cen----q112 is described. Clinical features include short stature, microcephaly, unusual facies with narrow forehead, short nose, malar hypoplasia, protruding alveolar ridges and incisors, receding chin, relatively long philtrum, and large ears. In addition, he had bilateral inguinal herniae cryptorchidism with hypogonadism, pulmonic stenosis, and spastic quadriplegia. Normal activity of beta-glucuronidase was found in the patient's leukocytes. This finding suggests that the gene is not in the deleted region, narrowing the smallest region of overlap to 7q112----q22.

Váradi syndrome (OFD VI) or Opitz trigonocephaly syndrome: overlapping manifestations in two cousins.

We report on 2 cousins, offspring of consanguineous matings, with multiple congenital anomalies. Square face, frontal bossing with metopic ridge, small anteverted nose, flat nasal bridge, slanted palpebral fissures, and epicanthal folds contributed to an unusual appearance. Multiple bucco-alveolar frenula and notched inferior alveolar ridges were present at birth and one had a notched uvula and submucous cleft of the hard palate. Both had congenital heart anomalies, micropenis, and cryptorchidism. Persistence of Müllerian structures was documented at necropsy in one patient. The surviving patient was mentally retarded and had unilateral central hexadactyly and partial agenesis of the corpus callosum. Bulimia and episodic hyperthermia were attributed to hypothalamic dysfunction. Results of unstimulated endocrine studies and gonadotropin releasing hormone (GnRH), and human chorionic gonadotropin (HCG) stimulation tests were normal. The manifestations of the 2 patients overlap those reported in the OFD VI and Opitz trigonocephaly syndromes.

Uncomplicated familial hypospadias: evidence for autosomal recessive inheritance.

Uncomplicated hypospadias was found in eight members of a large, consanguineous Bedouin family. Virilization and fertility were normal in the only postpubertal individual. The inheritance is most likely autosomal recessive and we suggest that in some of the familial cases in which polygenic or multifactorial inheritance was previously proposed, homozygosity for recessive genes may be responsible for the increased risk to siblings. Dominantly transmitted hypertelorism with diastema was an independent and coincidental finding in this family.

Familial segregation of cervical ribs, Sprengel anomaly, preaxial polydactyly, anal atresia, and urethral obstruction: a new syndrome?

In a consanguineous Jewish family originating from Bombay, India, the propositus presented with anal atresia, micropenis, urethral obstruction with secondary prune belly, omphalocele, patent urachus, and cryptorchidism. The kidneys were dysplastic and he had the Potter phenotype with limb deformities. Additional findings included IUGR with microcephaly, congenital heart defects, spinal anomalies, and hypoplastic lungs. The mother and all three sisters had cervical ribs, and she and one sister had 11 pairs of thoracic ribs. The other two sisters had chronic immune thrombopenia. One of those had bilateral Sprengel deformity with homovertebral bones, club feet, and microcephaly and the other sister also had unilateral preaxial hexadactyly. Although familial segregation of cervical ribs and Sprengel deformity has been reported, the association of the findings in this family is unique and may represent a new syndrome. X-linked dominant transmission may explain the severe manifestations in the affected male, but other modes of inheritance may also apply.

Familial lipoid adrenal hyperplasia: genetic marker data and an approach to prenatal diagnosis.

Some of the anatomic endocrine, and genetic aspects of lipoid adrenal hyperplasia were studied in an inbred Israeli-Arab family with two affected sibs. One sib, a genetic female, presented with acute Addisonian crisis. Endocrine studies documented elevated ACTH levels and no detectable steroids of gonadal or adrenal origin. The other patient, a male pseudo-hermaphrodite, was found at autopsy to have typical lipoid adrenal hyperplasia and ectopic adrenal tissue adjacent to an intra-abdominal testicle. Complete vagina, uterus, and fallopian tubes were present in addition to the Wolffian structures. This unique observation supports the view that steroids may be necessary for Müllerian inhibitory factor to induce regression of Müllerian structures. The segregation of 27 autosomal markers was studied in one affected and five unaffected sibs. Genetic linkage to HLA, MNS, and GPT is unlikely. In addition, the affected sib is heterozygote for a haplotype of chromosome 1 which includes the Rh, Fy, PGM-1 systems. Determination of fetal gender by the combined use of ultrasonography and amniocentesis is suggested for prenatal diagnosis and improved risk counselling.

Familial simple hypohidrosis with abnormal palmar dermal ridges.

A brother and sister born to nonconsanguineous, Iranian Jewish parents were found to have simple hypohidrosis. Pilocarpine produced only little sweating, and external heat and physical effort were associated with elevation of body temperature. Abnormal palmar dermal ridges were considered to be associated with paucity of sweat pores and glands. Biopsy supported this view since only one normal sweat gland and duct was found in a 5 mm punch.

Chromosome Abnormalities in infants with prune belly anomaly: association with trisomy 18.

Two infants are described with "prune belly anomaly" (PBA) and concomitant trisomy 18. Severe abdominal distention was detected prenatally in one by ultrasonographic study, and in the second child at birth. Other chromosome abnormalities previously associated with PBA also are reviewed. The prune belly anomaly constitutes a malformation sequence that is causally nonspecific and which may occur in diverse aneuploidy syndromes. Aneuploidy is important to detect in prenatally diagnosed cases in which intrauterine fetal treatment is being considered.

Interstitial deletion 2q14q21.

A girl with multiple congenital anomalies and a tendency to severe pyogenic infections was found to have an interstitial deletion of chromosome band 2q14----q21. Unusual facial manifestations included enophthalmos, long philtrum, micrognathia, narrow forehead, prominent glabella, and depressed nasal bridge. Unilateral corneal clouding, with Peters-like anomaly; agenesis of the corpus callosum; brain atrophy; and heart, kidney, hand, and dermatoglyphic anomalies were additional findings. Eye anomalies were observed in five of 22 patients with deletions of chromosome 2q. In comparing these cases, it seems that deletions of bands 2q21 and 2q31 are variably associated with microphthalmia, corneal clouding, cataracts, and Peters anomaly. Measurement of protein C and interleukin-1 (IL-1) did not show a gene dose effect, but the pyogenic infections and low IgA found in this patient may reflect an abnormality of IL-1 not detectable by our methods.

Duchenne muscular dystrophy and idiopathic hyperCKemia segregating in a family.

A 7-month-old boy with gross motor delay and failure to thrive presented with rhabdomyolysis following an acute asthmatic episode. During hospitalization an electrocardiographic conversion to a Wolff-Parkinson-White type 1 (WPW) pattern took place. Duchenne muscular dystrophy (DMD) was suspected based on elevated creatine kinase (CK) serum levels, muscle biopsy, and family history. The diagnosis was confirmed by molecular analysis, which documented a deletion corresponding to cDNA probe 1-2a in the dystrophin gene, in the propositus and in an affected male cousin of his mother. "Idiopathic" hyperCKemia was found in the propositus, his father, and 5 of his relatives. We suggest that the unusually early and severe manifestations of DMD in this patient may be related to the coincidental inheritance of the maternal DMD gene and of a paternal gene, causing hyperCKemia.

Autosomal recessive Peters anomaly, typical facial appearance, failure to thrive, hydrocephalus, and other anomalies: further delineation of the Krause-Kivlin syndrome.

Two cousins and an unrelated patient, all offspring of consanguineous parents, presented with Peters anomaly, unusual facial appearance, disproportionate short stature, retarded skeletal maturation, and a variable degree of mental retardation. Variable digital, cardiac, CNS, and urogenital anomalies were present. The inheritance is probably autosomal recessive. The condition is a distinct clinical entity for which we suggest the eponym Krause-Kivlin syndrome. Peters anomaly is thought to result from abnormal migration of neural crest cells. A similar mechanism was implicated in the pathogenesis of other disorders of the anterior chamber. The presence of Peters anomaly, and possibly of other corneal endothelial disorders in a newborn infant, should alert the clinician to the possibility of this syndrome. Communicating hydrocephalus (or brain atrophy) and polyhydramnios were documented in two patients, potentially allowing prenatal diagnosis in secondary familial cases.