Affected sibling pairs

Greenberg DA, Hodge SE, Sowinski J, Nicoll D. Excess of twins among affected sibling pairs with autism Implications for the etiology of autism. Am J Hum Genet2QQ 69 1062-7. 

The best available evidence indicates that myoadenylate deaminase deficiency is genetically determined via autosomal recessive inheritance (1) Two affected sibling pairs have now been reported >. (2) Patients with the muscle deficit have normal... 

The existence of non-HLA genes in many of the HLA associated diseases was established from theoretical considerations involving population prevalence, risks to relatives, and HLA IBD values in affected sib pairs (28-30). Type-1 diabetes shows an increased risk in siblings over population prevalence (Xs) of 15 in Caucasian populations (30), of which HLA contributes 3.4 approximately 45% of the type-1 diabetes genetic component under a multiplicative model (31). 

Clinically, VLCAD can be divided into mild and severe variants. In our series, the severe group comprised patients with evidence of cardiomyopathy at presentation or cardiomyopathy in a previously affected sibling and/or early presentation (3 days to 3 months of life) with generally a poor clinical outcome. The mild group contained two adult presentations with predominantly skeletal muscle involvement and four children (two pairs of affected siblings from two families) surviving with relatively Httle clinical intervention in the early years. 

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