Familial occurrence of 18q-

Summary An unusual segregation of the partial long arm deletion of a chromosome 18 is reported. This aberration was found in the feeble-minded mother and in her 4 daughters. The fifth child has XXY-Klinefelter's syndrome. The carriers of 18q — in this family reveal small stature, microcephaly, and mental deficiency in the range from feeble-minded to severe imbecility. Other characteristic features commonly found in patients with 18q — syndrome, as mid-face retraction, downward slanting mouth, heart defect, and atretic ear canals were not observed.     

Familial hypoadrenalism]

Congenital hypoadrenalism was diagnosed in a 18-month boy. It is suspected that hypoplasia of the adrenals is determined genetically due to the similar course and the results of autopsy in his deceased sister.     

Homologous recombination among three intragene Alu sequences causes an inversion-deletion resulting in the hereditary bleeding disorder Glanzmann thrombasthenia.

The crucial role of the human platelet fibrinogen receptor in maintaining normal hemostasis is best exemplified by the autosomal recessive bleeding disorder Glanzmann thrombasthenia (GT). The platelet fibrinogen receptor is a heterodimer composed of glycoproteins IIb (GPIIb) and IIIa (GPIIIa). Platelets from patients with GT have a quantitative or qualitative abnormality in GPIIb and GPIIIa and can neither bind fibrinogen nor aggregate. Very few genetic defects have been identified that cause this disorder. We describe a kindred with GT in which the affected individuals have a unique inversion-deletion mutation in the gene for GPIIIa. Patient platelets lacked both GPIIIa protein and mRNA. Southern blots of patient genomic DNA probed with an internal 1.0-kb GPIIIa cDNA suggested a large rearrangement of this gene but were normal when probed with small GPIIIa cDNA fragments that were outside the mutation. Cytogenetics and pulsed-field gel analysis of the GPIIIa gene were normal, making a translocation or a very large rearrangement unlikely. Additional Southern analyses suggested that the abnormality was not a small insertion. We constructed a patient genomic DNA library and isolated fragments containing the 5' and 3' breakpoints of the mutation. The nucleotide sequence from these genomic clones was determined and revealed that, relative to the normal gene, the mutant allele contained a 1-kb deletion immediately preceding a 15-kb inversion. The DNA breaks occurred in two inverted and one forward Alu sequence within the gene for GPIIIa and in the left, right, and left arms, respectively, of these sequences. There was a 5-bp repeat at the 3' terminus of the inversion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Familial studies on the occurrence of natural autoantibodies

Natural autoantibodies are often incidentally found in healthy individuals who are not first-degree relatives of known patients with autoimmune diseases. In an attempt to examine whether there exists a familial tendency in the production of such natural autoantibodies, 134 healthy members of 32 families were examined for antibodies against ss-DNA, ds-DNA, poly (I), poly (G), cardiolipin, histones, Sm, RNP, SS-A (Ro) and SS-B (La), using an enzyme-linked immunosorbent assay. Only 16 of the 134 subjects (11.9%) were found to possess autoantibodies in their sera in a titer exceeding the mean by 3 SD, and none of the 'positive' subjects were related. We conclude that in contrast to the familial occurrence of the autoantibodies of first-degree relatives of patients with autoimmune disease, there is no familial tendency in the occurrence of natural autoantibodies.     

Familial occurrence of unilateral biphalangeal duplication of the thumb.

Duplication of the thumb is not an uncommon condition and the biphalangeal type is considered to be a sporadic event. We report the familial occurrence of a unilateral thumb polydactyly type 4 of Wassel (12) or preaxial polydactyly type 1 of Temtamy (11).