distal monosomy 17q

Distal monosomy 17q is a very rare chromosomal disorder characterized by multiple congenital abnormalities affecting the craniofacial region, limbs, heart, respiratory system, and other organs. It results from deletions at the distal end of chromosome 17q, although the precise genetic basis is still under investigation. Affected individuals typically present with a range of structural abnormalities along with growth, motor, and intellectual challenges. Because prevalence estimates are not well established, it is described as extremely rare.

The clinical features of distal monosomy 17q are observed across several systems. Craniofacially, individuals often present with microcephaly, posteriorly rotated ears, upslanted palpebral fissures, a narrow mouth, abnormality of the philtrum, hypertelorism, prominent metopic ridge, and microtia. Abnormal limb findings such as abnormal thumb morphology, deviation of a finger, micromelia, abnormal metacarpal and hip bone morphology, and distinctive dermatoglyphics including bilateral single transverse palmar creases are also common. In addition, many affected individuals exhibit cardiac anomalies including a patent ductus arteriosus, abnormal cardiac septum formation, and broader cardiovascular system abnormalities, while respiratory insufficiency, hepatomegaly, optic atrophy, and premature birth are frequently reported. Not all individuals experience every feature, and severity varies considerably.

Distal monosomy 17q is caused by a chromosomal deletion involving the distal portion of the long arm of chromosome 17. The precise genetic basis is still under investigation, and no specific gene has been conclusively linked to the condition. Information regarding the pattern of inheritance is not available, meaning that at this time, it is unclear whether the deletion occurs as a sporadic event or through other mechanisms. Families are encouraged to consult with a genetic counselor to better understand potential recurrence risks and to discuss comprehensive genetic evaluation.

Currently, management focuses on supportive care and symptom management rather than a specific treatment targeting the underlying chromosomal deletion. Treatment is tailored to the individual and typically involves a multidisciplinary team that may include cardiologists, neurologists, orthopedic specialists, and other experts. Regular surveillance is an essential part of long-term care, helping to identify and address complications across various organ systems early. Families are advised to discuss options with their healthcare team and to consider genetic counseling, as well as seeking support from specialists familiar with multi-system disorders.

The prognosis for individuals with distal monosomy 17q is variable, with many cases being associated with severe complications and a high risk of early lethality. Outcomes depend on the extent of the deletion and the number and severity of organ systems involved. With current standards of care, including comprehensive and ongoing surveillance, management is increasingly tailored to individual needs, allowing for timely interventions that can improve quality of life. Families are encouraged to seek support through genetic counseling and connect with specialists, as outcomes continue to evolve with advances in modern care.