Differential Diagnosis

The patient's presentation of polydactyly, webbed neck, feminine voice, and less pubic hair suggests a complex syndrome that could involve genetic, hormonal, and developmental aspects. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Turner Syndrome: This condition, characterized by the partial or complete absence of one X chromosome in females (45,X), often presents with physical features such as a webbed neck, short stature, and gonadal dysgenesis leading to reduced pubic hair and a high-pitched or feminine voice. Polydactyly can also be seen in some cases. The combination of these features makes Turner Syndrome a strong candidate for the diagnosis.

• Other Likely Diagnoses

  • Klinefelter Syndrome: Typically presenting in males with an extra X chromosome (47,XXY), it can lead to a feminine voice, reduced body hair, and sometimes developmental abnormalities. However, polydactyly and webbed neck are less common, making it less likely but still a consideration.
  • Noonan Syndrome: This genetic disorder can present with a webbed neck, developmental delays, and sometimes polydactyly. While it affects both males and females, the presence of a feminine voice and reduced pubic hair might be less typical, depending on the specific genetic mutation and the individual's sex.

• Do Not Miss Diagnoses

  • Androgen Insensitivity Syndrome (AIS): Particularly the partial form, could present with reduced body hair and a feminine voice in genetic males. However, polydactyly and webbed neck are not typical features, making this a less likely but critical diagnosis not to miss due to its implications for gender identity and potential health risks.
  • Congenital Adrenal Hyperplasia (CAH): Certain forms can lead to atypical genitalia and developmental issues, but the specific combination of polydactyly, webbed neck, and the described voice and hair patterns would be unusual.

• Rare Diagnoses

  • Smith-Lemli-Opitz Syndrome: A rare genetic disorder that can include polydactyly among its features, along with developmental delays and sometimes unusual physical characteristics. The syndrome primarily affects males, and while it could potentially explain some of the patient's features, the specific combination mentioned is not typical.
  • Ellis-van Creveld Syndrome: Characterized by polydactyly and other skeletal abnormalities, it might be considered if the primary features were polydactyly and webbed neck, but the syndrome does not typically include the hormonal or voice changes described.

Each of these diagnoses requires careful consideration of the patient's full clinical presentation, including any additional symptoms or signs not mentioned, and would likely involve genetic testing and hormonal evaluations to confirm.