American Journal of Medical Genetics最新文献

Two sisters born to consanguineous Lebanese parents had mental retardation and epilepsy, brachymetacarpalia, hirsutism, bulbous soft nose, thick floppy ears with abnormal configuration and gingival hypertrophy. One girl presented additionally with tetralogy of Fallot and the other with congenital hypothyroidism and bilateral ureteral stenosis. These manifestations resemble the syndrome of hypertrichosis-gingival fibromatosis-mental retardation and seizures of Anavi et al. [1989: Dev Med Child Neurol 31:538-542] but our two girls additionally have brachymetacarpia. The inheritance seems to be autosomal recessive. These two sisters may represent a hitherto undescribed syndrome. We discuss the findings in our patients in relation to the literature.

We report the first observation of parent-to-child transmission of dysgnathia, a rare disorder characterized by severe mandibular hypoplasia or agenesis, ear anomalies, microstomia, and microglossia. Patient 1 was noted prenatally by ultrasound to have severe micrognathia and, after birth, abnormal ears with canal stenosis and non-contiguous lobules located dorsally to the rest of the pinnae, normal zygomata, severe jaw immobility and microstomia with an opening of only 4 to 5 mm, hypoplastic tongue, and cleft palate. The 21-year-old mother of patient 1 was born with severe micrognathia requiring tracheostomy, microglossia, cleft palate with filiform alveolar bands, abnormal pinnae, and decreased conductive hearing. Dysgnathia is thought to result from a defect in the development of the first branchial arch. A similar phenotype has been seen in Otx2 haplo-insufficiency and endothelin-1 homozygous null mice, suggesting that these genes contribute to branchial arch development. Our report of a long-surviving mother and her daughter with non-syndromal dysgnathia may lead to identification of the molecular basis of these findings and provide insight into the genetics of first branchial arch formation. The survival of patient 1 and patient 2 beyond the neonatal period has implications for improvements in prenatal diagnosis and counseling and for neonatal treatment of this condition.

Two sibs are described with an unbalanced 4;6 translocation resulting in partial trisomy 6p and monosomy for distal 4p. Growth retardation, psychomotor retardation, and characteristic facial appearance are present. The facial anomalies include high prominent forehead, blepharoptosis, blepharophimosis, high nasal bridge, bulbous nose, long philtrum, small mouth with thin lips, and low-set ears. Both children have small kidneys and have had proteinuria since early childhood. The older boy developed progressive renal disease including hypertension and renal failure necessitating renal transplantation at age 18 years. Renal biopsy of the younger girl also indicates significant renal involvement. Progressive renal disease is likely an important part of the trisomy 6p phenotype.

The clinical presentation of mitochondrial DNA (mtDNA) disorders is quite diverse. Very often, the initial symptoms do not fit a specific disease, and diagnosis is difficult to make. We describe a patient who presented with macrocytic anemia. Extensive biochemical and clinical work-up failed to provide an etiology for the macrocytic anemia. The patient over the course of 6 years developed gait problems, exercise intolerance, episodic vomiting, short stature, dermatological problems, and recurrent infection. At age 8 years she had encephalopathy with ataxia and dysphagia. The presence of elevated lactate, bilateral basal ganglia calcification, and ragged red fibers led to mtDNA mutational analysis. A novel 4.4-kb deletion from nucleotide position 10,560 to nucleotide position 14, 980 was identified in muscle biopsy. The same heteroplasmic mtDNA deletion was present in blood, buccal cells, and hair follicles, but not in mother's blood, consistent with sporadic mutation in the patient. This case emphasizes the importance of considering mtDNA disorder in patients with multisystemic symptoms that cannot be explained by a specific diagnosis.

The recent finding that a subset of patients with Rothmund-Thomson syndrome (RTS) have mutations of a helicase gene has prompted reexamination of the phenotypes of individuals diagnosed with this disorder. We report on two patients with variable presentations of RTS. Initial presenting symptoms included growth deficiency and absent thumbs in one patient and osteogenic sarcoma and poikiloderma in the second patient. The growth-deficient patient was diagnosed with growth hormone deficiency and had a subnormal response to growth hormone supplementation. Neither malformations nor growth deficiency were present in the patient with osteogenic sarcoma, and her only other manifestation of RTS was poikiloderma. The diagnosis of RTS should be considered in all patients with osteogenic sarcoma, particularly if associated with skin changes.

Hydrometrocolpos (HMC) and post-axial polydactyly (PAP) are common to both McKusick-Kaufman syndrome (MKS) and Bardet-Biedl syndrome (BBS). We review reported cases of MKS and BBS presenting with HMC and PAP early in life to determine if there are clinical features that allow discrimination between the two syndromes as the primary features of retinitis pigmentosa, obesity, learning disability in BBS are age-dependent. We did not find any phenotypic features that allowed reliable differentiation between the two syndromes in the neonatal period. However, uterine, ovarian, and fallopian tube anomalies are more common in BBS patients, and it may be that these clinical features prove to be useful discriminating features. We conclude that sporadic female infants with HMC and PAP cannot be diagnosed with MKS until at least age 5 years and that monitoring for the complications of BBS should be performed in these patients.

In Down syndrome (DS) brain an early, selective accumulation of amyloid beta (Abeta) peptides ending at residue 42 (Abeta42) occurs. Whether this event depends on an altered processing of amyloid beta precursor protein (APP) or on defective clearance is uncertain. To investigate this issue, we measured Abeta species 40 and 42 in plasma from 61 patients with DS, 77 age-matched normal controls, and 55 mentally retarded subjects without chromosomal abnormalities. The Abeta 40 and 42 plasma levels were then correlated with apolipoprotein E (apoE) genotypes in all groups of cases, and with I. Q. and Mini Mental Status Examination values in DS subjects. Both Abeta species were significantly elevated in DS compared to control groups, and the extent of their increase reflects that expected from APP gene overexpression. Plasma levels of Abeta 40 and 42 did not correlate with apoE genotypes in DS and control cases, and with the extent of mental retardation in DS subjects. The results indicate that accumulation and clearance of plasma and cerebral Abeta are regulated by different and independent factors.

Mosaic trisomy 7 is a rare condition that can be seen in individuals with Blaschkolinear skin pigmentary variation, somatic asymmetry, and variable other clinical anomalies. In any patient presenting with Blaschkolinear skin pigmentary variation, varying degrees of asymmetrical growth disturbance, developmental delay, and a normal lymphocytic karyotype, chromosomal mosaicism may be present. To rule out tissue-specific or occult chromosomal mosaicism, it is recommended to culture and karyotype skin fibroblasts, since lymphocyte cell lines may not demonstrate the abnormal cell line. Early diagnosis is of paramount importance, since early physical, occupational, and speech/language therapy can greatly improve the developmental outcome of these patients. We report on a fourth patient with trisomy 7 mosaicism in whom early diagnosis and developmental therapy contributed to an improved developmental outcome when compared with patients in previous reports. Early intervention can greatly benefit patients with this diagnosis, especially in minimizing the aggressive behavior associated with communication difficulties. Our patient has milder manifestations than the previously reported patients with no seizure activity or asymmetry and fewer cells with trisomy 7.