Glanzmann thrombasthenia is a bleeding disorder that is characterized by prolonged or spontaneous bleeding starting from birth. People with Glanzmann thrombasthenia tend to bruise easily, have frequent nosebleeds (epistaxis), and may bleed from the gums. They may also develop red or purple spots on the skin caused by bleeding underneath the skin (petechiae) or swelling caused by bleeding within tissues (hematoma). Glanzmann thrombasthenia can also cause prolonged bleeding following injury, trauma, or surgery (including dental work). Women with this condition can have prolonged and sometimes abnormally heavy menstrual bleeding. Affected women also have an increased risk of excessive blood loss during pregnancy and childbirth.\n\nAbout a quarter of individuals with Glanzmann thrombasthenia have bleeding in the gastrointestinal tract, which often occurs later in life. Rarely, affected individuals have bleeding inside the skull (intracranial hemorrhage) or joints (hemarthrosis).\n\nThe severity and frequency of the bleeding episodes in Glanzmann thrombasthenia can vary greatly among affected individuals, even in the same family. Spontaneous bleeding tends to become less frequent with age.

The classic features of TARP syndrome are talipes equinovarus, atrial septal defect, Robin sequence (micrognathia, cleft palate, and glossoptosis), and persistent left superior vena cava. Not all patients have all classic features. Some patients have the additional features of central nervous system dysfunction, renal abnormalities, variable cardiac anomalies including hypertrophic obstructive cardiomyopathy, and variable distal limb defects including syndactyly. Most patients die in late prenatal or early postnatal stages (summary by Kaeppler et al., 2018).

Inherited disorders of fibrinogen affect either the quantity (afibrinogenemia and hypofibrinogenemia; 202400) or the quality (dysfibrinogenemia; 616004) of the circulating fibrinogen or both (hypodysfibrinogenemia; see 616004). Afibrinogenemia is characterized by the complete absence of immunoreactive fibrinogen. Bleeding due to afibrinogenemia usually manifests in the neonatal period, with 85% of cases presenting umbilical cord bleeding, but a later age of onst is not unusual. Bleeding may occur in the skin, gastrointestinal tract, genitourinary tract, or the central nervous system, with intracranial hemorrhage being reported as the major cause of death. Patients are susceptible to spontaneous rupture of the spleen. Menstruating women may experience menometrorrhagia. First-trimester abortion is common. Both arterial and venous thromboembolic complications have been reported (summary by de Moerloose and Neerman-Arbez, 2009). Hypofibrinogenemia is characterized by reduced amounts of immunoreactive fibrinogen. Patients are often heterozygous carriers of afibrinogenemia mutations and are usually asymptomatic. However, they may bleed when exposed to trauma or if they have a second associated hemostatic abnormality. Women may experience miscarriages. Liver disease occurs in rare cases (summary by de Moerloose and Neerman-Arbez, 2009).

A rare lethal congenital myopathy syndrome characterized by decreased fetal movements and polyhydramnios in utero and the presence of akinesia, severe hypotonia with respiratory insufficiency, absent reflexes, joint contractures, skeletal abnormalities with thin ribs and bones, intracranial and retinal hemorrhages and decreased birth weight in the neonate.

SMALED2B is a severe neuromuscular disorder with onset in utero. Affected individuals show decreased fetal movements and are usually born with congenital contractures consistent with arthrogryposis multiplex congenita (AMC). After birth, they have severe hypotonia and muscle atrophy as well as respiratory insufficiency due to muscle weakness. Some patients may have dysmorphic facial features and/or abnormalities on brain imaging. Many patients die in early childhood (summary by Storbeck et al., 2017) For discussion of genetic heterogeneity of lower extremity-predominant spinal muscular atrophy, see SMALED1 (158600).

Autosomal dominant congenital disorder of glycosylation type Iw (CDG1WAD) is characterized by variable skeletal anomalies, short stature, macrocephaly, and dysmorphic features; about half of patients have impaired intellectual development. Additional features include increased muscle tone and muscle cramps (Wilson et al., 2021).

Congenital myopathy-2C (CMYP2C) is an autosomal dominant disorder of the skeletal muscle characterized by severe congenital weakness usually resulting in death from respiratory failure in the first year or so of life. Patients present at birth with hypotonia, lack of antigravity movements, poor head control, and difficulties feeding or breathing, often requiring tube-feeding and mechanical ventilation. Decreased fetal movements may be observed in some cases. Of the patients with congenital myopathy caused by mutation in the ACTA1 gene, about 90% carry heterozygous mutations that are usually de novo and cause the severe infantile phenotype. Some patients with heterozygous mutations have a more typical and milder disease course with delayed motor development and proximal muscle weakness, but are able to achieve independent ambulation (CMYP2A; 161800). The severity of the disease most likely depends on the detrimental effect of the mutation, although there are probably additional modifying factors (Ryan et al., 2001; Laing et al., 2009; Sanoudou and Beggs, 2001; Agrawal et al., 2004; Nowak et al., 2013; Sewry et al., 2019; Laitila and Wallgren-Pettersson, 2021). For a discussion of genetic heterogeneity of congenital myopathy, see CMYP1A (117000).