<unk> <unk>  involves the deficiency or absence of one or more central digits of the hand or foot and is also known as split hand–split foot malformation (SHFM). The hands and feet of people with<unk>  are often described as "claw-like" and may include only the thumb and one finger (usually either the little finger, ring finger, or a syndactyly of the two) with similar abnormalities of the feet. It is sometimes referred to as "lobster claw"<unk> .<unk>  dysplasia describes abnormalities of structures derived from the embryonic ectoderm. These abnormalities affect both the superficial<unk>  layer, as well as the mesectodermal layer constituted by the neural crest.<unk>  dysplasia<unk>  dysplasia is characterized by absent sweat glands resulting in dry (hypohydrotic), often scale-like skin, sparse and usually coarse scalp hair that is often blonde, sparse eyebrows and eyelashes, and small brittle nails. In addition, abnormalities of<unk>  derivatives, neuroectodermal derivatives, and mesectodermal derivatives are often found. The<unk>  derivative abnormalities can affect the epidermis including mammary, pituitary and sweat glands, as well as hairs, dental enamel, nails, lens, and the internal ear. Neuroectodermal derivatives that can be affected include sensory placodes, cutaneous pigmental cells, and hair buds. Mesectodermal derivatives affected can include the dermis, hypodermis, dentin, head muscles and conjunctival cells, cervicofacial vascular endothelial cells, and part of the maxillofacial skeleton. The hypohydrotic symptoms of<unk>  dysplasia described above are evidenced not only in the skin of affected individuals, but also in their phonation and voice production. Because the vocal folds may not be as hydrated as is necessary during the adduction phase of vocal fold vibration (due to lack of lubrication), a complete seal may not be accomplished between the folds and mucosal wave movement may be disrupted. This results in air escapement between the folds and the production of breathy voice, which often accompanies the skin abnormalities of<unk>  dysplasia. Facial<unk> ing There is much discrepancy in the literature regarding the exact nature of the facial<unk> ing involved in EEC. Some authors claim that the<unk> ing involved in EEC is always<unk>  lip +/- palate and use this marker as a means of distinguishing EEC from other<unk> s, such as AEC<unk>  (ankyloblepharon,<unk>  dysplasia, and<unk> ing) in which other types of<unk> ing are found. Other authors include<unk>  palate only (CPO) in conjunction with<unk>  and<unk>  dysplasia as sufficient for a diagnosis of EEC. Speech deficits The speech deficits associated with EEC<unk>  are numerous. The<unk> ing often causes hypernasal speech and velopharyngeal incompetence. Because of this, compensatory articulation strategies including retruded articulation and glottal compensation are often incorporated into the patient's speech. Articulation is further impaired by the numerous dental anomalies, including missing or malformed teeth found in EEC<unk> . Language deficits are also associated with EEC<unk>  and are attributed to two factors. Conductive hearing loss due to ossicular anomalies is often encountered in patients with EEC<unk> , which can have significant impacts on language acquisition. Also, the impaired cognitive functioning that sometimes accompanies EEC can inhibit language acquisition.
Ectrodactyly–ectodermal dysplasia–cleft syndrome
Greig cephalopolysyndactyly syndrome
Saethre–Chotzen syndrome
Renal dysplasia-limb defects syndrome
Pelger–Huët anomaly
Tricho–rhino–phalangeal syndrome type 2
Goldberg–Shprintzen syndrome
Short rib–polydactyly syndrome