SNP Shot: Genomic Insights

Robinow syndrome is a rare genetic condition that primarily affects skeletal development. It presents in different forms, distinguished by the severity of symptoms and how it's inherited: either as autosomal recessive or autosomal dominant.

Autosomal recessive Robinow syndrome is marked by skeletal abnormalities. These include shortened long bones in the arms and legs (especially the forearms), unusually short fingers and toes (brachydactyly), wedge-shaped spinal bones (hemivertebrae) causing spinal curvature (kyphoscoliosis), fused or absent ribs, and short height. Individuals often have distinct facial characteristics: a wide forehead, prominent and widely spaced eyes, a short nose with an upturned tip, a wide nasal bridge, and a broad, triangle-shaped mouth. These facial features are sometimes called "fetal facies" due to their resemblance to a developing fetus's face. Other common features include underdeveloped genitalia in both sexes, and dental issues like crowded teeth and gum overgrowth. Kidney and heart problems can also occur. While intelligence is generally normal, developmental delays affect 10-15% of those with this form.

Autosomal dominant Robinow syndrome exhibits similar, but generally milder, signs and symptoms compared to the autosomal recessive type. Spine and rib abnormalities are uncommon in the dominant form, and short stature is less severe. A specific type of autosomal dominant Robinow syndrome involves increased bone density (osteosclerosis) in the skull bones, in addition to the typical symptoms. This subtype is known as the osteosclerotic form of Robinow syndrome.

Inheritance:

As mentioned, Robinow syndrome follows either an autosomal recessive or autosomal dominant inheritance pattern.

In autosomal recessive inheritance, both copies of a specific gene must have mutations for the condition to develop. Individuals with autosomal recessive Robinow syndrome inherit one mutated gene copy from each parent, who are typically carriers without showing symptoms themselves.

In autosomal dominant inheritance, only one mutated copy of a gene is enough to cause the disorder. Individuals with autosomal dominant Robinow syndrome may inherit the mutated gene from an affected parent. In other instances, the mutation is new and occurs spontaneously in the affected individual, even if there's no family history of the condition.