Sharp rise in rare chromosomal disorders diagnosis rate

2 June 2014

UK Charity Unique has said that diagnosis rates for rare chromosomal disorders have risen sharply.

Unique provides information and support for patients and families affected by rare chromosomal disorders. It estimates that around 30% of all UK children with complex developmental disorders are now being diagnosed with individually rare chromosomal disorders, due to the equally rapid expansion of genetic testing capacity.

The charity says that collectively, rare chromosome disorders affect at least one in every 200 people, an incidence higher than that of Down’s syndrome and cerebral palsy put together. The disorders are noted to range in severity, depending on the position and extent of chromosomal alteration, from those resulting in profound and complex disability, to others that show no obvious symptoms but can cause infertility or recurrent miscarriages – often the case for balanced translocations.

The first national Rare Chromosome Disorder Awareness Week begins today on 2nd June 2014; this is a new initiative spearheaded by Unique that aims to boost awareness of chromosomal disorders and the difficulties they pose to affected families – in part because the conditions are so little known and in many cases also poorly understood.

The advent of modern genetic testing technologies is indeed resulting in increasing rates of diagnosis for children in whom a chromosomal cause of disability would previously have been suspected but unconfirmed. The advantages of diagnosis are multiple, offering emotional benefits to families and potentially helping them to access care services more easily; it also avoids the need for multiple exploratory medical interventions, and can aid reproductive planning for parents as the risk of recurrence can be estimated.

However, for rare disorders the problem remains that little or nothing may be known about the likely prognosis for the child. Efforts are already underway to create, maintain and share internationally databases (such as DECIPHER) and to identify new genetic causes of existing disease (such as the DDD project), and these can help clinicians to link very small numbers of related cases and improve care for patients and families; and to help interpret previously unknown genetic abnormalities in medical terms.

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